text:
|Publication number
|Publication type
|Application number
|Publication date
|Dec 3, 2002
|Filing date
|May 20, 1999
|Priority date
|May 20, 1999
|Fee status
|Publication number
|Darin Ferguson, Robert Clouston, Anthony Talerico
|Original Assignee
|Cisco Technology, Inc.
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (36), Non-Patent Citations (10), Referenced by (24), Classifications (14), Legal Events (4)
|External Links: USPTO, USPTO Assignment, Espacenet
The present invention is related to the following copending and commonly assigned U.S. Patent Applications:
U.S. patent application Ser. No. 08/999,271, now U.S. Pat. No. 6,131,117 titled Technique for Correlating Logical Names with IP Addresses on Internetworking Platforms, by Wayne Clark et al., filed on Dec. 29, 1997;
U.S. patent application Ser. No. 09,315,550 still pending titled, Method and Apparatus for SNA/IP Correlation with Multiple DLSw Peer Connections, by Darin Ferguson et al., filed herewith;
U.S. patent application Ser. No. 09,315,441 still pending titled, Method and apparatus for Determining SNA Sessions Using Various Protocols for Transport Based on Filter Criteria, by Darin Ferguson et al., filed herewith;
U.S. patent application Ser. No. 09,315,443 still pending titled, Method and Apparatus for Determining a Path for a Session Using Various Protocols for Transport, by Darin Ferguson et al., filed herewith; and
U.S. patent application Ser. No. 09,315,284 still pending titled, Method and Apparatus for Establishing a Database Used for Correlating Information Gathered via SNMP, by Darin Ferguson et al., filed herewith, each application of which is hereby incorporated by reference as though fully set forth herein.
The present invention relates to computer networks and, more particularly, to management of entities in a mixed Advanced Peer to Peer Networking (APPN) and Data Link Switching (DLSW) computer network.
Data communications in a computer network involves the exchange of data between two or more entities interconnected by communication links and subnetworks. These networks are typically software programs executing on hardware computer platforms which, depending on their roles within a network, may serve as host stations, end stations or intermediate stations. Examples of intermediate stations include routers, bridges and switches that interconnect communication links in subnetworks; an end station may be a computer located on one of the subnetworks. More generally, an end station connotes a source of or target for data that typically does not provide routing or other services to other computers on the network. A local area network (LAN) is an example of a subnetwork that provides relatively short-distance communication among the interconnected stations; in contrast, a wide area network (WAN) facilitates long-distance communication over links provided by public or private telecommunications facilities.
End stations typically communicate by exchanging discrete packets or frames of data according to predefined protocols. In this context, a protocol represents a set of rules defining how the stations interact with each other to transfer data. Such interaction is simple within a LAN, since these are typically "multicast" networks: when a source station transmits a frame over the LAN, it reaches all stations on that LAN. If the intended recipient of the frame is connected to another LAN, the frame is passed over a routing device to that other LAN. Collectively, these hardware and software components comprise a communications network and their interconnections are defined by an underlying architecture.
Most computer network architectures are organized as a series of hardware and software levels or "layers" within each station. These layers interact to format data for transfer between, e.g., a source station and a destination station communicating over the network. Specifically, predetermined services are performed on that data as it passed through each layer, and the layers communicate with each other by means of the predefined protocols. This design permits each layer to offer selected services to other layers using a standardized interface that shields the other layers from details of actual implementation of the services. The lower layers of these architectures are generally standardized and implemented in hardware and firmware, whereas the higher layers are usually implemented in the form of software. Examples of such communications architectures include the System Network Architecture (SNA) developed by International Business Machines (IBM) Corporation and the Internet Communications Architecture.
The Internet architecture is represented by four layers termed, in ascending interfacing order, the network interface, internetwork, transport and application layers. The primary internetwork layer protocol of the Internet architecture is the Internet Protocol (IP). IP is primarily a connectionless protocol that provides for internetworking routing, fragmentation and reassembly of exchanged packets-generally referred to as "datagrams" in an Internet environment-and which relies on transport protocols for end-to-end reliability. An example of such a transport protocol is the Transmission Control Protocol (TCP), which is implemented by the transport layer and provides connection-oriented services to the upper layer protocols of the Internet architecture. The term TCP/IP is commonly used to denote this architecture; the TCP/IP architecture is discussed in Computer Networks, 3rd edition, by Andrew S. Tanenbaum, published by Prentice-Hall, PTR in 1996, all disclosures of which are incorporated herein by reference, particularly at pages 28-54.
SNA is a communications framework widely used to define network functions and establish standards for enabling different models of IBM computer to exchange and process data. SNA is essentially a design philosophy that separates network communications into several layers termed, in ascending order, the physical control, the data link control, the path control, the transmission control, the data flow control, the presentation services and the transaction services layers. Each of these layers represents a graduated level of function moving upward from physical connections to application software.
In the SNA architecture, the data link control layer is responsible for transmission of data from one end station to another. Bridges or devices in the data link control layer that are used to connect two or more LANs so that end stations on either LAN are allowed to access resources on the LANs. Connection-oriented services at the data link layer generally involve three distinct phases: connection establishment, data transfer and connection termination. During connection establishment, a single path or connection, e.g., an IEEE 802.2 logical link control type 2 (LLC2) or "data link control" (DLC) connection, is established between the source and destination stations. Once the connection has been established, data is transferred sequentially over the path and, when the LLC2 connection is no longer needed, the path is terminated. Reliable communication of the LLC2 (DLC) is well known and described by Andrew Tanenbaum in his book Computer Networks, Second Edition, published in 1988, all disclosures of which are incorporated herein by reference, especially at pages 253-257.
FIG. 1 is a schematic block diagram of a conventional computer network 100 having a host computer coupled to a Token Ring (TR) network TR1 and an end station coupled to TR2. The TR networks are of the type that support Source/Route Bridging (SRB) operations with respect to the contents of a routing information field (RIF) of a frame. The host computer is preferably a SNA host entity comprising a host mainframe computer 110 coupled to a channel-attached router or front end processor (FEP), hereinafter referred to as the "host network connection" 112; in addition, the end station is an SNA entity 114 comprising a "physical unit" (PU), i.e., a component that monitors the station's resources, and a "logical unit" (LU) which consists of logical services by which a user may access the SNA network. An SRB bridging device B1 interconnects TR1 and TR2 such that the SRB network 100 effectively functions as a LAN.
The PU entity communicates with the host by exchanging TR frames over LLC2 connections or sessions through the SRB network. Each TR frame 120 includes a RIF 122 that contains source route information in the form of ring number/bridge number pair "hops" within a path between the stations. For example, the RIF 122 of TR frame 120 transmitted by the PU to host contains [0021.0010]. An LLC2 session is established between the stations using a special TR frame, called an explorer frame.
The explorer frame is used by a source (PU) to "discover" the path to a destination (host); thereafter, a Set Asynchronous Balanced Mode Extended (SABME) frame is sent from the PU to the host to establish a logical connection between the end stations, and the host responds to the SABME frame with an Unnumbered Acknowledgment (UA) frame. Once the UA frame is received by the PU, a connection is established between the source and destination, and these stations communicate by exchanging TR information (INFO) and acknowledgment frames until the logical link SNA session is completed.
For example, the PU transmits an INFO frame over TR2 and through BRI and TR1 to the host. Upon successfully receiving the INFO frame, the host responds by transmitting an LLC2 Receive/Ready (RR) acknowledgment frame over the SRB network to the PU. This INFO/RR exchange continues until the PU has successfully transmitted all of its data and the host has successfully received all of that data. Session completion is then initiated by a Disconnected Mode (DM) frame being transmitted from the PU to the host; the disconnection is thereafter acknowledged by the host responding with a UA frame. The LLC2 frames (packets) are described by Radia Perlman in her book Interconnections, Bridges and Routers, published by Addison Wellesly Publishing Company, in 1992, all disclosures in which are incorporated herein by reference, particularly at pages 33-34.
In a SNA network, applications executing on end stations typically access the network through LUs of the stations; accordingly, in a typical SNA network, a communication session may connect two LUs in a LU—LU session. Activation and deactivation of such a session is addressed by Advanced Peer to Peer Networking (APPN) functions. The APPN functions generally include session establishment and session routing within an APPN network. FIG. 2 is a schematic block diagram of an APPN network 200 comprising two end stations, which may be configured as a host network connection entity 202 and a PU entity 212, coupled to token ring (TR) LANs TR1-2, respectively. During session establishment, an end station (such as PU 212) requests an optimum route for a session between two LUs; this route is calculated and conveyed to PU 212 by an intermediate station (e.g., station 216) via a LOCATE message exchange through the network 200. Thereafter, a "set-up" or BIND message is forwarded over the route to initiate the session. The BIND includes information pertaining to the partner LU requested for the session.
Intermediate session routing occurs when the intermediate stations 206, 216, configured as APPN network nodes (NN), are present in a session between the two end nodes. As can be seen, the APPN network nodes are further interconnected by a WAN 210 that extends the APPN architecture throughout the network. The APPN network nodes forward packets of an LU—LU session over the calculated route between the two APPN end nodes. An APPN network node is a full-functioning APPN router node having all APPN base service capabilities, including session services functions. An APPN end node, on the other hand, is capable of performing only a subset of the functions provided by an APPN network node. APPN network and end nodes are well-known and are, for example, described in detail in Systems Network Architecture Advanced Peer to Peer Networking Architecture Reference IBM Doc SC30-3422 and APPN Networks by Jesper Nilausen, printed by John Wiley and Sons, 1994, at pgs 1-83.
FIG. 3 is a schematic block diagram of the software architecture of an APPN node 300. As noted, application 302 executing on an APPN end node communicates with another APPN end node through a LU—LU session; LU 304 within each end node functions as both a logical port for the application to the network and as an end point of the communication session. The session generally passes through a path control module 312 and a data link control (DLC) module 316 of the node, the latter of which connects to various network transmission media. A control point (CP) module 308 coordinates performance of all APPN functions within the node 300 and, in the case of an APPN network node, is in session with a CP in adjacent APPN network nodes. Through these CP—CP sessions, all network nodes in an APPN environment coordinate operation of the network, and exchange, inter alia, configuration information. By interfacing with a configuration database 310, the CP coordinates management of the actual data communication links (DLC) in the network.
When functioning as an APPN router node, such as NN 206, an intermediate session routing (ISR) module 305 maintains a portion of the session in each "direction" with respect to an adjacent network node, such as NN 216 of network 200. In response to receiving the BIND message during session establishment, path control 312 and ISR 305 are invoked to allocate resources for the session. In particular, each entity 206, 216 allocates a local form session identifier for each direction of the session. Collectively, each of these individually-established "local" sessions form the logical communication session between the LUs 304 of the end node entities 202, 212.
The APPN router node may provide Dependent LU Requester (DLUR) services on behalf of the PU ("dependent" LU) in network 200 while the host network connection 202 may provide Dependent LU Server (DLUS) services. As described herein, the DLUS host is coupled to the DLUR router by way of a "pipe" connection over which control traffic for the dependent session flows. The DLUR router essentially functions as a "surrogate" for the downstream PU with respect to the DLUS host such that the control information flows over the network to the PU by way of the DLUR router.
Data Link Switching (DLSw) is a mechanism for forwarding SNA protocol frames over, e.g., a TCP/IP backbone WAN such as the Internet. In traditional bridging, the data link connection is end-to-end, i.e., effectively continuous between communicating end stations. A stream of data frames originating from a source station on a source LAN traverses one or more bridges specified in the path over the LLC2 (DLC) connection to a destination station on a destination LAN. In a network implementing DLSw, by contrast, the LLC2 connection terminates at a local DLSw device entity, e.g., a router. An example of a DLSw network arrangement may comprise a host DLSw router connected to a host computer via a host LAN and a remote DLSw router connected to a remote LAN having a destination station. The LANs that are accessed through the DLSw routers may appear as SRB subnetworks attached to adjacent rings; each of these adjacent rings manifest as a virtual ring within each DLSw router that effectively terminates the SRB network.
A DLSw network is formed when two DLSw devices interconnect the end nodes of the APPN network by way of the IP network; the DLSw devices preferably communicate using a Switch-to-Switch protocol (SSP) that provides packet "bridging" operations at the LLC (i.e., DLC) protocol layer. FIG. 4 is a schematic block diagram of a DLSw network 400 having a TCP/IP cloud 410 disposed between host and remote SRB subnetworks 420, 430. Each SRB subnetwork comprises a DLSw router 1, 2 coupled to the host network connection 402 and PU/LU 412 via TR1 and 2, respectively. The DLSw routers function as end points between TCP sessions over the TCP/IP cloud when transporting TR frames associated with DLC sessions over that intermediate network.
Broadly stated, each DLSw router establishes a "peer relationship" to the other DLSw router in accordance with a conventional capabilities exchange message sequence, and the logical and physical connections between these routers connect the subnetworks into a larger DLSw network. To establish a peer connection in accordance with an implementation of DLSw switching, the host DLSw router first opens logical TCP (Read/Write) "pipe" connections to the remote DLSw router using a conventional socket technique to create a socket into the transport layer of the protocol stack. Once the TCP pipes are established, the SSP protocol is used to transport the capabilities exchange messages between the two DLSw routers.
The capability exchange messages contain various parameters, such as the number of pipes used for communicating between the DLSw routers and the largest frame size supported by the routers. Each DLSw router responds to each capability exchange message issued by its peer router with a capability exchange response message. Upon completion of the exchange, each router reconfigures itself to "act upon" the agreed capabilities and the peer connection is established. Establishment of a peer connection can occur automatically upon "boot-up" of each DLSw router; that is, as soon as a DLSw router activates, it connects with its DLSw peer. The DLSw forwarding mechanism is well known and described in detail in Request For Comment (RFC) 1795 by Wells & Bartky, 1995 at pgs 1-91.
Upon receiving a TR frame from a source on the host SRB subnetwork that is destined for a destination on the remote subnetwork, the host DLSw router employs the SSP protocol to communicate with its DLSw peer router by forwarding the native TR frame over the TCP/IP network to the remote SRB subnetwork. That is, the TR frame received at the host DLSw router from the source is encapsulated within a SSP protocol frame and forwarded over the TCP/IP cloud to the remote DLSw router. The source route information contained in the RIF of each TR frame terminates inside the virtual ring of the DLSw router; notably, the RIF information is locally stored at the DLSw router.
The host DLSw router then multiplexes the LLC2 session data stream over a conventional TCP transport connection to a remote DLSw router. LLC2 acknowledgment frames used to acknowledge ordered receipt of the LLC2 data frames are "stripped-out" of the data stream and acted upon by the host DLSw router; in this way, the actual data frames are permitted to traverse the IP cloud to their destination while the "overhead" acknowledgment frames required by the LLC2 connections for reliable data delivery are kept off the cloud. The LLC2 connections from the source LAN to the host transmitting DLSw router, and from the remote receiving DLSw router to the destination LAN, are entirely independent from one another. Data link switching may be further implemented on multi-protocol routers capable of handing DLSw devices as well as conventional (e.g., SRB) frames.
DLSw routers can establish multiple parallel TCP sessions using well-known port numbers. All frames associated with a particular LLC2 connection typically follow a single designated TCP session. Accordingly, SNA data frames originating at the PU are transmitted over a particular LLC2 connection along TR2 to DLSw2, where they are encapsulated within a designated TCP session and transported over the TCP/IP cloud 410. The encapsulated messages are received by DLSwl, decapsulated to their original frames and transmitted over a corresponding LLC2 connection of TR1 to the host in the order received by DLSw2 from the PU.
The LLC2 connection between the PU and host is identified by a data link identifier (ID) 460 consisting of a pair of attachment addresses associated with each end station. Each attachment address is represented by the concatenation of a media access control (MAC) address (6 bytes) and a LLC service access point (SAP) address (1 byte). Specifically, each attachment address is classified as either a target address comprising a destination MAC (DMAC) and a destination SAP (DSAP), or an origin address comprising a source MAC (SMAC) and source SAP (SSAP) addresses. The attachment addresses are contained in the TRs frame exchanged between the PU and host entities.
Furthermore, the designated TCP session is identified by a pair of circuit IDs 470, each comprising a 64-bit number that identifies the LLC2 circuit within a DLSw circuit. The DLSw circuit ID generally comprises a data link circuit port ID (4 bytes) and a data link correlator (4 bytes). A pair of circuit IDs along with a data link ID uniquely identifies a single end-to-end circuit through the network. Notably, each DLSw router maintains a table 450 comprising a plurality of data link ID and corresponding DLSw circuit ID pair entries. In order to associate LLC2 frame traffic with a corresponding DLSw circuit when communicating over the IP cloud, each DLSw router typically indexes into the table (the "DLSw table") using a data link ID to find the corresponding DLSw circuit IDs.
The DLSw circuit information described above, including the data link IDs, are available to a network operator of a network management station (NMS) 480 via a Simple Network Management Protocol (SNMP) configured to access DLSw management information base (MIB) tables within the routers. The MIB and SNMP protocol, and their use in providing network management information between SNMP management stations and agents are well-known and described in, e.g., SNMP, SNMPv2 and RMON by William Stallings, printed by Addison Wesley Publishing Company, 1996.
The orientation of the MAC/SAP attachment addresses of the data link IDs acquired from each router is dependent on the proximity of the SNA entity to which the router is connected. For example, the remote DLSw router identifies the PU MAC/SAP attachment address as origin and the host network connection MAC/SAP attachment address as target, whereas the host DLSw router identifies the PU and host connection addresses in reverse order. The DLSw routers do not, however, maintain the name of the PU, which is a common way for an operator to identify a session.
A problem involving a PU session in the network 400 may be diagnosed by the network operator using a conventional approach that correlates SNA frame traffic sessions to DLSw routers for a network having a peer connection over an IP cloud between DLSw peer routers. Typically, management of the SNA entities takes place on the host in accordance with a network management application program, such as NetView, executing on the host. The application can access the status of the PU and LU entities by virtue of their definitions contained in a specialized data structure 490 of the host network connection 402. This data structure is a virtual telecommunication access method (VTAM) table 490 having entries whose contents define all the PUs and LUs with respect to the host. The content definitions of the entries comprise a name (e.g. PU name 492) along with a block number and ID number (IDBLK/IDNUM 494) that uniquely identifies each PU on a network at a given time.
The NetView application manages those SNA resources known to it; as used in this context, the term "managing" means that the application program can check and change the status of the resources, and can further control those resources to acquire, e.g., information leading to the traffic patterns of the resources. However, the NetView application cannot manage the component in the routers that encapsulate SNA traffic. As noted, the DLSw routers are preferably managed by the SNMP tool executing on the NMS which communicates with SNMP agents resident on the routers.
According to the conventional approach, the NMS communicates with an SNMP agent in each DLSw router to acquire DLSw MIB information including a data link ID identifying a DLSw circuit associated with the router. Since the host computer "owns" SNA sessions in the network, it maintains SNA-specific information (in addition to the PU name) such as the MAC/SAP addresses 496 for the host network connection and the PU on VTAM 490 in the host. The NMS issues commands to the host over a pipe connection 485 to retrieve the SNA-specific information from VTAM. The SNA-specific information retrieved from VTAM 490 does not, however, include information with respect to the DLSw routers that are routing the session traffic.
In response to a query from the operator specifying a PU name of the session, the NMS compares the MAC/SAP addresses retrieved from VTAM with the data link IDs in the MIBs to identify a DLSw circuit at each router. The NMS then uses the orientation of the MAC/SAP attachment addresses from the routers to distinguish between the host and remote DLSw routers. Thereafter, the NMS can draw the topology of the DLSw network, including the DLSw circuit and PU session path, to isolate any failures in the network.
However, if the session path traverses a heterogeneous network having both DLSw and APPN devices, correlation cannot be done efficiently using the conventional approach primarily because the host (VTAM) does not store the MAC/SAP address information of the PU in such a mixed APPN/DLSw network. That is, the host "sees" a 5 logical connection between its DLUS service and the DLUR service terminating at the APPN router; accordingly, the MAC/SAP address information stored in VTAM that is typically associated with the PU is actually the address of the APPN (DLUR) device. Data intended for the PU is sent from the host to the DLUR and it is the responsibility of the DLUR to forward that information to the PU. As a result, the SNA-specific information retrieved from VTAM includes the MAC/SAP address of the APPN DLUR device.
As noted, the DLSw circuit information acquired by the NMS via the SNMP queries includes the MAC/SAP address information of the host and the PU. Yet this DLSw circuit information cannot be directly correlated with the VTAM supplied information because the "PU" information differs (the actual PU MAC/SAP information versus the DLUR MAC/SAP information). Moreover, the APPN DLUR device maintains information (such as the PU name) of the PU but it does not recognize the presence of DLSw devices routing session traffic between it and the PU. Therefore, the conventional correlation approach cannot be effectively used to correlate information between SNA/IP segments of a mixed APPN and DLSw network.
The present invention is directed to providing the appropriate tools to draw an SNA session over such a network topology. In particular, the invention provides a method to correlate SNA traffic sessions that traverse both DLSw and APPN devices to enable a complete view of a mixed APPN and DLSw network. More specifically, the present invention is directed to a technique for correlating SNA/IP information within a heterogeneous network having APPN and DLSw routers to enable drawing of a SNA session and diagnosing of problems associated with the session.
The present invention comprises a technique for efficiently correlating information pertaining to entities of a mixed Advanced Peer to Peer Networking (APPN) and Data Link Switching (DLSw) computer network. The entities comprise System Network Architecture (SNA) host mainframe ("host") and physical unit (PU) entities, along with DLSw and APPN/DLSw devices. Broadly stated, the technique involves identifying a SNA session path as using Dependent Logical Unit Requester (DLUR) services of the APPN/DLSw device and thereafter obtaining media access control (MAC)/service access point (SAP) information needed to correlate the SNA session to the DLSw peer devices and an associated DLSw peer circuit connection. A DLSw peer connection is established between the APPN/DLSw device and its remote "peer" DLSw device that comprises DLSw circuits identified by, inter alia, data link identifiers (IDs) comprising attachment addresses of the DLUR and PU entities.
According to the invention, the technique involves determining whether the network includes an APPN device by identifying the PU as "going through" a DLUR. A virtual telecommunication access method (VTAM) display of an active PU at a network management station (NMS) indicates whether the device is, e.g., an APPN router performing DLUR services on behalf of the PU. If the network includes such an APPN node, the DLUR name retrieved from VTAM is of the form NETID.CP name. Note that the NMS communicates with the host over a "pipe" connection to acquire SNA-specific information from a VTAM table structure at the host. The SNA-specific information acquired from VTAM includes, inter alia, (i) the MAC/SAP addresses of the APPN DLUR device; (ii) the DLUR name for the PU, (iii) a control point (CP) name of the PU; and (iv) an ID block number/ID number (IDBLK/IDNUM) of the PU.
Next, the technique determines whether the DLUR device is a manageable router and, if so, correlates the APPN/DLUR name of the router to an Internet Protocol (IP) address. A node is considered manageable if it responds to simple network managment protocol (SNMP) queries from the NMS with requested information using, e.g., an APPN management information base (MIB) query to determine its CP name. Here, the NMS has access to a list of IP addresses of the routers. If the router does not have APPN functionality, it responds negatively to the MIB query; otherwise, the router responds with its NETID.CP name in the APPN MIB. A simple correlation is then performed between the APPN addressing (NETID.CP name) and SNMP addressing (IP address) for that router.
A next step of the inventive technique is to find a logical connection (i.e., a "link station") between the APPN router and the PU. In accordance with one aspect of the invention, a DLUR MIB may be used to query the DLSw/APPN router. The DLUR MIB includes a field (dlurPuLsName) that identifies the link station for a particular PU that is used to communicate with the DLUR router. If the router does not support the DLUR MIB, the CP name of the PU provided by VTAM may be used as the basis of a query into the APPN MIB (appnLsTable) for a matching CP name (appnLsAdjCpName) associated with the logical link station. If the CP name is not provided, the IDBLK/IDNUM of the PU provided by VTAM may be used to query the appnLsTable to find a matching appnLsPartnerNodeId entry associated with the link station. If the MIBs cannot be used, native device commands (such as router show commands) can be employed to collect this information.
The inventive technique then proceeds to obtain the MAC/SAP address of the APPN link station associated with the PU, which is the remote MAC/SAP address for the DLSw circuit. Preferably, this information is obtained from an APPN MIB. The MAC/SAP address of the APPN router is also obtained from the APPN MIB; this address information is the local MAC/SAP address for the DLSw circuit. The order of the DLSw peer routers is then determined. In the illustrative embodiment, the APPN/DLSw router is the router coupled to the host-side of the network since it identifies the MAC/SAP addresses of its DLUR function as its origin attachment address and the MAC/SAP addresses of the PU as its target attachment address. Furthermore, DLSw router is the router coupled to the remote-side of the network since it identifies the MAC/SAP addresses of the PU as its origin attachment address and the MAC/SAP addresses of the APPN/DLUR as its target attachment address.
Once the order of the DLSw peer routers is determined, the topology of the mixed APPN/DLSw network may be drawn illustrating the relationship between the routers and the SNA entities of the network. Graphical representations of network on the display may include identifying the host-based, APPN/DLSw (DLUR) device with a different icon than the DLSw device. The invention thus allows the NMS to correlate an SNA session over a complex network with a network path that includes DLSw and APPN devices. More specifically, the present invention provides management tools that enable viewing of all segments of the network traversed by the SNA session to thereby enable isolation of a network problem to one of the network segments for a more specialized and targeted diagnosis.
The above and further advantages of the invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which like reference numbers indicate identical or functionally similar elements:
FIG. 1 is a schematic block diagram of a conventional computer network having a host computer and end station coupled to a plurality of token ring local area networks to form a source-route bridge (SRB) network;
FIG. 2 is a schematic block diagram of a prior art Advanced Peer to Peer Networking (APPN) network including APPN nodes;
FIG. 3 is a schematic block diagram of the software architecture of an APPN node;
FIG. 4 is a schematic block diagram of a data link switching (DLSw) network;
FIG. 5 is a block diagram of an illustrative embodiment of a heterogeneous computer network, including a DLSw device node and an APPN/DLSw hybrid device node for interconnecting various subnetworks and communication links on which the present invention may advantageously operate;
FIG. 6 is a schematic block diagram of protocol stacks contained within DLSw and APPN/DLSw nodes of a heterogeneous computer network similar to the network of FIG. 5; and
FIG. 7 is a schematic block diagram showing a logical link station connection between two APPN nodes;
FIG. 8 is a flowchart illustrating the steps involved in a novel correlation technique for a mixed APPN and DLSw network in accordance with the present invention;
FIG. 9 is a schematic block diagram of an alternate embodiment of a mixed APPN and DLSw network having a hybrid DLSw/APPN device node disposed between a hostside DLSw device and a remote-side DLSw device that may be advantageously used with the present invention; and
FIG. 10 is a flowchart illustrating the steps involved in the novel correlation process for the host-side circuit of the alternate embodiment of the mixed APPN and DLSw network.
FIG. 5 is a highly schematic block diagram of a heterogeneous computer network 500 comprising a plurality of subnetworks 502, 506 interconnected by a wide area network (WAN) 504. Each subnetwork 502, 506 is preferably of a type that supports source-route bridging (SRB) operations with respect to the contents of a routing information field (RIF) of a frame. The subnetworks are attached to a plurality of stations preferably embodied as internetworking computer platforms and comprising a host computer 510, an end station 512, a network management station (NMS) 580 and a plurality of intermediate stations 600, 650. In particular, the host computer 510 is coupled to a token ring (TR) local area network (LAN) TR1 to form subnetwork 502 and the end station 512 is coupled to TR2 to form subnetwork 506.
The host computer is preferably a Systems Network Architecture (SNA) host entity comprising a mainframe computer coupled to a channel-attached router or front end processor (FEP), hereinafter referred to as the host network connection or "host" 510. The end station is preferably a SNA Physical Unit (PU) entity functioning in accordance with Advanced Peer to Peer Networking (APPN) Dependent Logical Unit Requestor (DLUR) services. In addition, the intermediate station 650 is a data link switching (DLSw) device or "router", whereas intermediate station 600 may comprise two independent devices, such as an APPN device and a DLSw device (router). In the illustrative embodiment described herein, however, the intermediate station 600 is an APPN/DLSw router. The APPN/DLSw router 600 preferably incorporates a DLUR function and the host 510 incorporates a Dependent LU Server (DLUS) function; these functions communicate via an APPN session over a logical link 575 of TR1. As a result, the network 500 comprises an APPN portion (between the host and APPN function of router 600) and a DLSw portion (between the DLSw function of router 600 and router 650).
Each station typically comprises a plurality of interconnected elements, such as a processor, a memory and an input/output (I/O) unit. The memory may comprise storage locations addressable by the processor and I/O unit for storing software programs and data structures associated with the inventive mixed network correlation technique. The processor may comprise processing elements or logic for executing the software programs and manipulating the data structures. An operating system, portions of which are typically resident in memory and executed by the processor, functionally organizes the station by, inter alia, invoking network operations in support of software processes executing on the station. It will be apparent to those skilled in the art that other processor and memory means, including various computer readable media, may be used for storing and executing program instructions pertaining to the technique described herein.
The I/O unit, in turn, connects the station to mass storage devices, such as disks, and to the subnetworks. The NMS may further include a conventional display monitor with a display screen and cursor control devices, such as a keyboard, connected to I/O unit. A window environment, such as a graphical user interface (GUI), is preferably displayed on the screen as a graphical display to facilitate interactions between a network operator and the station. For the NMS and intermediate stations, the disk may function as a database for storing network information, as described further herein. Typically, the I/O unit receives information, such as control, address and data signals, from the keyboard or the database, and provides that information to the processor for display on the screen or for transfer over the subnetworks.
The routers 600, 650 interconnect the subnetworks 502, 506 and facilitate communication among the host and PU over the WAN, which is preferably a Transmission Control Protocol/Internet protocol (TCP/IP) network cloud 504. Communication among the stations is effected by exchanging discrete packets or frames of data according to predefined protocols and services; an example of a connection-oriented service that may be used to ensure reliable communication between the PU station and the host station is an IEEE 802.2 Logical Link Control Type 2 (LLC2) or Data Link Control (DLC) connection service.
Heterogeneous network 500 is formed when APPN/DLSw hybrid node 600 is connected to DLSw node 650 via the TCP/IP network 504. FIG. 6 is a schematic block diagram of protocol stacks 610, 660 within the nodes 600 and 650, respectively. Applications executing on SNA devices (stations) 602, 608 typically access the network through logical units (LUs) of the stations and communicate via LU—LU sessions. Hybrid node 600 functions to facilitate establishment and routing of these connection-oriented communication sessions within the network. To this end, protocol stack 610 preferably comprises an APPN layer 612 that contains the software modules described in FIG. 3.
The stack 610 also includes a TCP/IP layer 616 containing those layers of the Internet communications architecture protocol stack needed to establish, e.g., conventional connection-oriented, TCP communication sessions. Physical sublayers 622 and 626 specify the electrical, mechanical, procedural and functional specifications for activating, maintaining and de-activating the physical links 604 and 504 of the network. Protocol stack 660 of DLSw node 650 likewise includes a TCP/IP layer 666 and physical sublayers 672 and 676, which are functionally equivalent to those layers of protocol stack 610.
Each node 600, 650 further contains a DLSw layer 614, 664 and DLC layers 618, 620 and 668, 670, respectively, the latter layers providing a connection-oriented service via conventional DLC (LLC2) connections. The DLSw layers provide a mechanism for forwarding data frame traffic between devices 602, 608 over IP network 504. Note that there is a virtual DLC mechanism, similar to a port, that is used to communicate between the DLSw and APPN layers of router 600. Preferably, the DLSw layers 614, 664 cooperate to establish a peer relationship among themselves through the exchange of conventional capabilities exchange messages. These peer devices further cooperate to establish a conventional reliable transport connection, such as a TCP connection, that enables multiplexing of DLC (LLC2) data frames over the TCP transport between the devices.
As a result, the routers 600, 650 function as peers having logical and physical connections among them for interconnecting the subnetworks 502, 506 through the IP cloud 504 to form the mixed APPN/DLSw heterogeneous network 500. Each logical connection is manifested as a DLSw circuit having a data link identifier (ID) comprising media access control (MAC) and service access point (SAP) attachment addresses of the host and PU entities. For example, a DLSw circuit extends between APPN/DLSw router 600 and DLSw router 650 wherein, APPN/DLSw router 600 is configured as a host router coupled to TR1 and having a peer relationship with remote router DLSw 650 over IP cloud 504. The generation of DLSw circuits and identifiers is described in Request for Comment (RFC) 1795 by Wells & Bartky, 1995, while the establishment of TCP sessions is described in Internetworking with TCP/IP by Comer and Stevens, printed by Prentice Hall, 1991; all of these publications are hereby incorporated by reference as though fully set forth herein.
The RIF contains source route information in the form of ring number/bridge number tuples within a path between the stations. There is a RIF1 associated with subnetwork 502, and a RIF2 associated with subnetwork 506. The RIF information terminates inside a virtual ring of each router and is locally stored at the router, preferably on a DLSw table 550. Thus, RIF1 is "cached" at APPN/DLSw router 600 and RIF2 is cached at DLSw router 650. In addition, each DLSw table 550 contains data link and circuit IDs of the DLSw circuit associated with the respective DLSw layer in the router.
The DLSw portion of the network environment is managed by the NMS which, in the illustrative embodiment, is preferably a UNIX workstation configured to execute a network management application. An example of such an application is the CiscoWorks Blue Maps and CiscoWorks Blue SNA View product set, available from Cisco Systems, Inc. The CiscoWorks Blue product set provides a network operator with tools to draw a path of data transferred through the DLSw network. That is, the product set provides a view of an SNA data session extending from the PU through a DLSw peer connection to the host network connection. Using the product set, the operator may diagnosis and fix problems by understanding the data path through the network, and isolating the problem to one of the segments in the network. The present invention is an extension to the conventional approach for correlating SNA/IP information in a heterogeneous network having a mixed DLSw and APPN router configuration utilizing this product set.
The CiscoWorks Blue SNA View tool has a mainframe component and a UNIX workstation component that allows the NMS to retrieve SNA-specific information about the host and PU entities. The NMS 580 communicates with the host station over a TCP/IP (or LU 6.2) "pipe" connection 555 to acquire the SNA-specific information available from a virtual telecommunication access method (VTAM) table 520 at the host. The SNA-specific information acquired from VTAM includes (i) MAC/SAP addresses of the DLUS host and the DLUR router; (ii) the DLUR name for the PU, (iii) a control point (CP) name of the PU; (iv) an ID block number/ID number (IDBLK/IDNUM) of the PU and (v) the RIFI associated with subnetwork 502. This information is stored in a VTAM database 582 of the NMS.
The NMS 580 also communicates with the routers using a simple network management protocol (SNMP) to acquire IP-specific information. Here, the CiscoWorks Blue SNA View tool queries SNMP agents in the DLSw layers of the routers to acquire the information used to determine the peer relationships among the DLSw layers. The IP-specific information provided by each router includes (i) origin and target attachment (MAC/SAP) addresses of a DLSw circuit associated with the router, (ii) a circuit state of its DLSw circuit, (iii) its associated RIF, and (iv) an IP address of its peer DLSw layer router.
The NMS acquires the IP-specific information from the routers via DLSw management information base (MIB) structures for storage on a MIB database 584 of the NMS 580. An example of a DLSW MIB that may be advantageously used with the present invention is disclosed in Request for Comment (RFC) 2024, which is hereby incorporated by reference in its entirety. It should be noted that network management techniques other than SNMP, such as "sniffers" or show commands in the routers, may be used to acquire the circuit information from the routers.
The CiscoWorks Blue Maps tool further includes an APPN component whereby the NMS can communicate with the APPN layer 612 of router 600 using SNMP to acquire APPN-specific information via a DLUR and APPN MIB. Examples of MIBs that may be advantageously used with the present invention include (i) an IBM-6611-APPN-MIB described in RFC 1593, (ii) an APPN MIB described in RFC 2455, and (iii) a DLUR MIB described in RFC 2232, each of which is hereby incorporated by reference in its entirety. Note that the latter DLUR MIB is associated with the DLUR function within an APPN device, such as the DLSw/APPN router 600. Since VTAM is not configured to operate in accordance with SNMP, it does not implement the APPN MIB and thus cannot acquire the APPN-specific information described below.
Broadly stated, the DLUR MIB provides APPN-specific information relating to PU 512 and logical link 575 in the network 500, whereas the APPN MIB contains APPN-specific information pertaining to logical connections ("link stations") defined between, e.g., MAC/SAP addresses of APPN devices. FIG. 7 is a schematic block diagram showing the logical link station connection 700 between APPN nodes 1 and 2. The type of information acquired by the APPN MIB relates to the MAC/SAP addresses of the link. For example, APPN1 is assigned a MAC/SAP address wherein a SAP1 address is dedicated to an APPN (TR interface) port used to establish the logical link station 700 with another SAP2 address dedicated to an APPN port on APPN2. Referring to FIG. 5, assume APPN1 is the host 510 and APPN2 is the DLSw/APPN router 600; in this case, the MAC/SAP address of host 510 may be considered a local MAC/SAP address that establishes a link station connection 575 with a remote MAC/SAP port on DLSw/APPN router 600.
In accordance with the present invention, a technique is provided for correlating SNA sessions that traverse DLSW and APPN routers in the mixed APPN and DLSw heterogeneous network 500. The conventional correlation approach involves comparing the MAC/SAP addresses retrieved from VTAM at the NMS with the contents of the MIB database in order to retrieve a DLSw circuit ID (having matching MAC/SAP attachment addresses) which may then be used to identify the DLSw routers having a peer connection over the IP cloud. However, this conventional approach cannot be efficiently employed in a heterogeneous network having mixed APPN and DLSw routers. The present invention provides a technique for efficiently correlating SNA/IP information in such a heterogeneous network.
The novel technique generally involves identifying a session path as using DLUR services of an APPN router and thereafter obtaining the MAC/SAP information needed to correlate the SNA session to the DLSw peer routers. Determination of whether a router implements APPN DLUR services may be made by examining (at the NMS) the SNA-specific information retrieved from VTAM 520. For example if a router does not offer APPN services, the DLUR name for the PU is null. Since router 600 incorporates both DLSw and APPN services, there is a DLUR name associated with the PU 512 which, in the illustrative embodiment, is DLSwAPPN. The DLUR name is a network qualified name having a format of NETID.xxxxxxxx, wherein the latter is an 8-character string containing a control point (CP) name.
FIG. 8 is a flowchart illustrating the steps involved in a novel correlation technique (process) for a mixed APPN and DLSw network. The process begins at Step 800 and proceeds to Step 802 where the NMS determines whether the network incorporates an APPN router; this determination may be resolved by identifying the PU as "going through" a DLUR. A VTAM display at the NMS of an active PU indicates whether an APPN router performs DLUR services on behalf of the PU. Thus, a determination of whether the network incorporates an APPN node depends on whether the DLUR name retrieved from VTAM is null (Step 804). If so, the conventional correlation technique may be used to draw the topology of the resulting DLSw network. (Step 806). If the DLUR name is not null, there is a device that is a DLUR node having a name in the form NETID.CP name (Step 808). In the illustrative embodiment, the CP name is preferably DLSwAPPN.
Step 810 of the novel technique determines whether the DLUR node is a manageable router and, if so, correlates the APPN/DLUR name of the router to an IP address. A node is considered manageable if it responds to SNMP queries with the requested information. SNMP does not access nodes by NETID.CP name addressing, but rather uses IP addresses (or alternatively device names with domain name services to resolve IP addresses) of the nodes. Here, the NMS queries each router using the APPN MIB to determine its CP name. If the router does not have APPN functionality, it responds negatively to the MIB query and the process proceeds to query a next router in Step 811. If all of the routers respond negatively to the query, the conventional correlation technique may be used to draw only a subset of the network (Step 806); otherwise, the router responds with its NETID.CP name in the APPN MIB in Step 812. In the illustrative embodiment, the NMS queries each router by utilizing an existing database that includes a list of IP addresses of the routers. If a router responds with a DLUR name, then a simple correlation is performed between the APPN addressing (NETID.CP name) and SNMP addressing (IP address from OpenView) for that router in Step 814.
The next step of the inventive technique involves finding the APPN link station to the PU. Depending upon the router support and the type of PU, there are a number of ways to find the APPN link station. Step 816 involves utilizing the DLUR MIB to query the DLSw/APPN router (if the router implements the MIB) to fmd the link station. The DLUR MIB includes a table (dlurPuTable) having a plurality of entries (dlurPuEntries). Each entry is accessed by a PU name (obtained from VTAM) and contains a field whose contents (dlurPuLsName) identify the APPN link station for a particular PU that is used to communicate with the DLUR router. In order to access the correct entry of the DLUR MIB database table, the DLUR name of the PU retrieved from VTAM is used to find a matching dlurPuSscpSuppliedName.
The router may have many link stations to many PUs; this step involves identifying a particular link station to a particular PU MAC/SAP address. The link station is a logical APPN link that extends from the DLUR router over the IP network to the PU. This step is useful if the router implements the DLUR MIB and can provide the link station name in response to the SNMP DLUR MIB query. If the router does not support the DLUR MIB or if it did not provide a value for the dlurPuLsName field, then there are two alternative approaches to finding the link station to the PU. In order for the PU to communicate with VTAM and the host, the PU must be identified to VTAM as either a CP name or IDBLK/IDNUM. When an APPN router connects with a PU to establish a logical link, there is an XID exchange which includes an exchange of the CP name or IDBLK/IDNUM of the PU; the APPN router maintains the CP name or IDBLK/IDNUM of the PU associated with the link station connection. Therefore, all logical link station connections between the APPN router and the PU can be searched to find a matching CP name or IDBLK/IDNUM.
The CP name provided by VTAM may be used as the basis of a query into the APPN MIB (appnLsTable) for a matching CP name (appnLsAdjCpName) associated with the logical link station. Note that, in an alternate embodiment, the query may constitute a look-up operation into an NMS database having the appnLsTable. If the CP name is not provided and the router does not support the DLUR MIB, the dlurPuName may be used to find a matching appnLsAdjCpName in the appnLsTable. In addition, the IDBLK/IDNUM provided by VTAM may be used as the basis of the APPN MIB appnLsTable query (or a look-up operation into the NMS database) to find a matching appnLsPartnerNodeld entry. If SNMP is not utilized, an alternate embodiment involves the use of show commands issued to the router to provide this type of information.
Step 818 of the inventive technique involves finding the MAC/SAP address of the APPN link station associated with the PU, which is the remote MAC/SAP address for the DLSw circuit. There is a field (appnLsRemoteAddr) in the APPN MIB that contains the MAC/SAP information for the link; the NMS maintains a table of all link stations organized according to their MAC/SAP addresses. Step 820 of the inventive technique involves finding the MAC/SAP address of the APPN router, which is the local MAC/SAP address of the port coupled to the logical link station. This information is also provided by the APPN MIB (appnLsLocalAddr) and represents the local MAC/SAP address for the DLSw circuit.
As noted, the DLSw layers 614, 664 of the host and remote routers 600, 650 cooperate to form a DLSw circuit having origin and target MAC/SAP attachment addresses. The orientation of these attachment addresses of the data link IDs acquired from each router is dependent on the proximity of the SNA entity to which the router is connected. Notably, the SNA entity on the APPN portion of the network 500 is the DLUR function of the router 600 rather than the host 510. Therefore, the remote router identifies the MAC/SAP addresses of the PU as its origin attachment address and the MAC/SAP addresses of the DLUR (instead of the host network connection) as its target attachment address; the host router identifies the PU and DLUR addresses in reverse order.
More specifically, the MAC/SAP address of the DLUR router 600 is the port number to the virtual DLC connection of the DLSw circuit. The DLSw layer 614 "routes" the DLSw circuit data to the appropriate DLUR port on the APPN layer 612 of the router. For the particular link station utilized, Step 820 of the technique may also search for the MAC/SAP address in the DLSw/APPN router 600, which is effectively the virtual MAC/SAP address of the DLUR function of that router.
Once the MAC/SAP addresses of the PU and the DLSw/APPN router 600 are obtained, Step 822 comprises finding the DLSw circuit by determining the order of the DLSw peer routers. Referring to FIG. 5, APPN/DLSw router 600 is the host router that identifies the MAC/SAP addresses of the APPN/DLUR as its origin attachment address and the MAC/SAP addresses of the PU as its target attachment address, while DLSw router 650 is the remote router that identifies the MAC/SAP addresses of the PU as its origin attachment address and the MAC/SAP addresses of the APPN/DLUR as its target attachment address.
Once the order of the DLSw peer routers is determined, the topology of the mixed APPN/DLSw network may be drawn in Step 824, illustrating the relationship between the routers and the SNA entities of the network. Graphical representations of network on the display may include identifying the host-based, APPN/DLSw (DLUR) router 600 with a different icon than the DLSw router 650. The inventive process then ends in Step 826.
Advantageously, the invention provides the ability for network management program to correlate an SNA session over a complex network with a network path including both DLSw and APPN routers. As the complexity of the session path increases, so does the need for management tools to be able to view all the segments of the network that the session traverses, in order to isolate a network problem to one of the network segments for a more specialized and targeted diagnosis.
FIG. 9 is a schematic block diagram of an alternate embodiment of a mixed APPN and DLSw network 900 having a hybrid DLSw/APPN device node disposed between a host-side DLSwl device and a remote-side DLSw2 device. In this configuration, the devices are preferably routers wherein the host-side DLSw router is "peered" with the DLSw layer of the hybrid router, which is similarly peered with the remote-side DLSw router. The APPN/DLSw router thus has two DLSw circuits 1-2, wherein each of which it identifies the MAC/SAP addresses of its DLUR function as its origin attachment address. For the host-side circuit, the router identifies the MAC/SAP addresses of the host network connection 910 as its target attachment address, whereas for remote-side circuit, the APPN/DLSw router identifies the MAC/SAP addresses of the PU/LU 912 as its target attachment address. Correlation for the remote-side circuit may be achieved using the process described by the flowchart of FIG. 8.
FIG. 10 is a flowchart illustrating the steps involved in the novel correlation process for the host-side circuit of the alternate embodiment of the mixed APPN and DLSw network. The process begins at Step 1000 and proceeds to Step 1002 where the DLUS CP name of the host is obtained from the DLUR MIB (e.g., dlurPuActiveDlusName). Given a PU name, the CP name at the other end of the link station connection is that of the DLUS (host). In the illustrative embodiment, the CP name of the DLUS is preferably NETID.DLUS.
Once the DLUS CP name is obtained, Step 1004 involves searching the appnLsTable database (Step 814) to find the link station to the host having a matching remote (PU) CP name. In Step 1006, the remote MAC/SAP address of the link station is determined as in Step 818. That is, the link table in the APPN MIB has the remote MAC/SAP address of the link, which is the MAC/SAP address of the host. Step 1008 involves determining the local MAC/SAP address of the link station; the local MAC/SAP address is the address of the port used for the host link at the DLSw/APPN router. A different port may be used for the host-side portion of the DLSw circuit; therefore, it should not be assumed that the same local MAC/SAP address is used for the remote-side of the circuit.
Given the local MAC/SAP and remote MAC/SAP addresses, the technique proceeds to determine the DLSw circuit in Step 1010. In the case of the hybrid DLSw/APPN router, its local MAC/SAP address is the DLUR portion of the router and its remote MAC/SAP address is that of the host. For the DLSw host router, its local MAC/SAP address is that of the host and its remote MAC/SAP address is that of the DLUR router. Therefore, the inventive technique may be used to determine the MAC/SAP address pairs of the DLSw circuits for the host-side and remote-side portions of the network (which are different sets of MAC/SAP address pairs) and, thus in Step 1012, the network topology may be drawn. The process then ends in Step 1014.
The information collected by the CiscoWorks Blue Maps and CiscoWorks Blue SNA View tools are correlated according to the inventive technique to enable management of a network having a particular topology. The information is collected by the NMS 580 and stored on databases of tables that are accessed by a core Maps process executing on the NMS to draw the network topology upon demand. The SNA View tool is used to acquire information from the host (VTAM), but the Maps tool actually draws the view of the network topology on the NMS display; therefore, the inventive correlation technique may be considered an extension to the CiscoWorks Blue Maps product.
The foregoing description has been directed to specific embodiments of this invention. It will be apparent, however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the invention.
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|Nov 1, 2001
|David Vogt
|Provision of transparent proxy services to a user of a client device
|Jun 5, 2002
|Oct 24, 2002
|Eric Pouyoul
|System and method for dynamic, transparent migration of services
|Jan 22, 2002
|Dec 5, 2002
|Traversat Bernard A.
|Peer-to-peer communication pipes
|Jan 22, 2002
|Dec 12, 2002
|Traversat Bernard A.
|Resource identifiers for a peer-to-peer environment
|Oct 3, 2002
|Feb 27, 2003
|Abdelaziz Mohamed M.
|Peer-to-peer presence detection
|Nov 27, 2001
|May 29, 2003
|Takeshi Ishizaki
|Storage device with VLAN support
|Aug 21, 2003
|Oct 14, 2004
|Daisuke Shinohara
|Method and program for disclosing and providing services on network
|Dec 18, 2006
|May 3, 2007
|Traversat Bernard A
|Peer-to-Peer Communication Pipes
|Jan 24, 2006
|Jul 26, 2007
|Loyd Aaron J
|Determining network paths
|Feb 26, 2010
|Jun 24, 2010
|Conexant Systems, Inc.
|Methods and apparatus for data communications through packet networks
|U.S. Classification
|709/223, 709/238, 370/462, 709/249, 370/401, 709/227, 370/402, 370/362, 709/224
|International Classification
|Cooperative Classification
|European Classification
|May 20, 1999
Owner name: CISCO TECHNOLOGY, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FERGUSON, DARIN;CLOUSTON, ROBERT;TALERICO, ANTHONY;REEL/FRAME:009983/0701
Effective date: 19990519
|Jun 5, 2006
|Fee payment
Year of fee payment: 4
|Jun 3, 2010
|Fee payment
Year of fee payment: 8
|Jun 3, 2014
|Fee payment
Year of fee payment: 12


text:
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subset: commoncrawl


text:
- Explore community
- Identify
- Help
Observed: 22nd April 2011 By: RHoman
Added: 24th April 2011
Moths attracted to light, but content to sit on the vanes of a Heath Trap rather than going inside. On the night in question, there was a total of 10 Brimstones in and around the trap - a convocation of Brimstones?
Other observations of Brimstone Moth (Opisthograptis luteolata)
Species with which Brimstone Moth (Opisthograptis luteolata) interacts
Brimstone is an old word for sulphur -
25 April 2011 - 9:17am RogerR (not verified)
and one common allotrope of sulphur is known as "flowers of sulphur".
So perhaps a bunch of brimstones?


text:
Subtitled 'a practical guide to changing the world', Jim Shultz (better-known to NI readers in recent months for his dispatches from Cochabamba, Bolivia) has created here the nearest thing there is to a true democrat's riposte to, say, Mao's Little Red Book. Well, it's a bit bigger and more green, as you'd expect. And a good deal more uplifting than your average manual from, say, Microsoft, Sony or Readers' Digest. No self-professed democrat should be caught without it.David Ransom
This column was published in the November 2002 issue of New Internationalist. To read more, buy this issue or subscribe.


text:
New tread for a front wheel build:
Sent from my LG-H910 using Tapatalk
Fleabay find... paging Dertjunky
2008 BMC Fourstroke 19-559 ISO (RIP in peace)
2017 BMC Speedfox 25-622 ISO
2017 Salsa Timberjack 40-584 ISO
New bars and stem
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Originally Posted by JHart94949
New bars and stem
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Damnit! The mailman messed up and sent to you my goods ...
Got these in finally. Too bad the budget's shot again and it's all gonna just sit for months.
Since "Oil Can" finish isn't available I'm spending the rest of the evening polishing the cups out. Too bad they're also outed on the stainless 1-1/8" top-caps.
Easy-Off the black ano off that top cap and buff it out?
Cereal is breakfast soup.
dirt junkie,my budget huffy
82 linear inches of bar
cheapest stem
cheap bmx brakes,gets mounted on seatpost side,hooks to brake on aero ,yes 2 seperate rear brakes,im sure dirt junkie will have fun picking on me
That thing is gonna be tight!
Switched out the old Shimano SLX 670's for the Raceface Evolve SS crackset
I'm not sure what to run,650 b,26 ,I ride about 8 miles just to get to a gravel trail, hoping setup allow s both ,and ty
Originally Posted by Davidfklock
I'm not sure what to run,650 b,26 ,I ride about 8 miles just to get to a gravel trail, hoping setup allow s both ,and ty
What size is the frame made for?
Was a 26 inch display,never meant to be a bike,but bso,if I can fit a 26x2.0 or 26x 2.25 I can put 27.5 x 1.75 as long I can find the v brake arms.Outside and with are the same,I don't need aggressive tread on this.
Forekaster 29"X2.35
Renthal Apex 40mm
Ritchey 5NM TorqueKey
Wet lube.
Sent from my iPhone using Tapatalk
Wanted a lightweight pack to hold the essentials and more water than possible with two bottles, so got a Camelbak Classic with 2,5 litres reservoir. Was planning on getting an Evoc CC 3l instead, but the Camelbak was 30 cheaper and could buy it locally so had to give it a try. It's my first hydration pack, we'll see how I like it
Brown Santa came today!
2017 Fox 36 27.5 150mm
Originally Posted by Davidfklock
dirt junkie,my budget huffy
You bought three of them?
Originally Posted by NDD
Dude, I'm in Illinois. The only place anyone would come from that would say this area is hilly is Kansas.
Sent from my iPhone using Tapatalk
Enjoy the ride...
new bottlecage
Originally Posted by the_joe
Fleabay find... paging Dertjunky
Great find, sorry I skimmed that.
After buying my Parktool PCS-10 Bike Stand I thought I should start buying matching tools. I know I don't "need" them, because I have most of them in other brands and shapes, But I thought why not.
I do like the magnetic Parktool Bowl because I'm always placing stuff and forget where I placed them.
The Partktool Work Tray will be arriving next week
Soy Chingon
now with Mavic Crossmaxx Elite 29 wheels less one kilogram ! No excuse , pedal damn it !
It's always fun seeing everyone's new toys.
A bad day of cycling is better than a good day at work
Work Truck - Dassault Falcon 7X
Revelate Designs frame bag and Salsa carry anything bar rack and dry bag. I'm finally mostly ready for bikepacking.
Sent from my iPhone using Tapatalk
New rubbers...
29x2.6 NN next to a 2.2 Trail King; still waiting on new rims to come in
- Canfield Nimble 9 - Retired
Niner Rip 9 (2016)
Canfield Nimble 9 Boost (2017)
Nextie Crocodile 50s
Still debating on hubs, but I think I'm gonna try my hand at lacing these myself.
¯\_(ツ)_/¯ Yeah, why not?
Originally Posted by ARandomBiker
Nextie Crocodile 50s
Still debating on hubs, but I think I'm gonna try my hand at lacing these myself.
It's a fun learning experience! I've got a few rides on my first set and it very satisfying knowing that I built my own wheels. I'd highly recommend getting a Park TM-1 and Roger Musson's ebook that has everything you need to know.
+1 on that ^
Got a few new parts installed today!
Swapped out my 32T for a 30T NW (the start of this season is getting pretty rough this year with that 32)
Got my carbon bars installed and also put a Knog Oi bell on the right side of the handle bars. It's a rather polite sounding bell and blends right in. Beats shouting for the hikers to hear you coming. Between this and a Hope hub, they should hear me coming now.
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I tried that Knog Oi in the 22.2mm variety. It wasn't loud enough for me. You gotta keep ringing it until you get a response. The 31.8mm version (for road handlebars) is another story though. Using a Timberline right now (got it from Jenson with 15% off coupon), but think the Spurcycle v2 will be the one to get.
Don't be afraid of criticism. Don't be afraid to be the voice of reason. Focus on educating yourself, not educating others.
First 27.5" experience after 13 yrs of using a 26".
Pumped for summer rides in the NW.
Just noticing the reflectors in the pic. Those are now off the bike!
Got my partner in crime a MIPS equipped skidlid.
In serving the wicked, expect no reward, and be thankful if you escape injury for your pains.
New rear derailleur cable!
J/K. New 26x2.8" WTB Ranger/Minion DHF and new Hope Pro4/Stan's Flow MK3 wheelset. Loving 26+ so far!
There actually is a new cable in there, too! While everything isn't exactly new, it's the first pic I got to show it all together. And to anyone thinking of building their own wheels, do it, you won't regret it!
Forum Rules


text:
Having problems with your Eureka Vacuums ?
My Eureka vacuum model 4471 does not pick up - the bag is new??
Answers :
Check to see if the hose and the dirt inlet by the brush roll is open and not clogged. Also if you haven't replaced the belt in a awhile, it may have stretch to the point that it isn't turning the brush roll under load.
Repair Help & Product Troubleshooting for Eureka Vacuums
Tips for a great answer:- Provide details, support with references or personal experience .
- If you need clarification, ask it in the comment box .
- It's 100% free, no registration required.
Suggested Questions/Answers :
My Eureka vacuum model 4471 does not pick up - the bag is new??
Check to see if the hose and the dirt inlet by the brush roll is open and not clogged. Also if you haven't replaced the belt in a awhile, it may have stretch to the point that it isn't turning the brush roll under load. ... Eureka Vacuums
Hello, I have a problem with my Eureka Powerline bagged upright vacuum. It has a 12 amp motor and is model #4352, Type D. It was probably bought new in 1998. My problem is, while vacuuming today the motor seemed to slow down all of the sudden and then began smelling like burning rubber. I shut the vacuum off to check for blockages but could not find anything blocked. When I then turned it on again it runs but seems to only be running at 1/2 the motor speed and still has the rubber buring smell.
It sounds like a rubber sealing in the motor has come loose and is being constantly rubbed against the walls of the motor with would cause the smell and loss of motor speed caused by the fricton of rubber against the rod so if you can get to the moto ... Vacuums
Red "bag is full" indicator shows even though new bag has been put in and vacuum cleaner wont pick up. Also floor adjustment does not adjust. This is for a powerforce model 3522 series
The red light tell you that it is sensing a full bag. But a clog in the hose or the inlet down by the brush roll will also do this. ... Vacuums
I have a Eureka Contour model 2900 type A upright vacuum, the roller works fine nothing clogged, took it apart motor blade is free of debris, no suction from tube and blasts OUT air from the front HEPA filter location. New bag, New belt, nothing in hose.any clues as to why this can be happenning? Air should not be blasting out of the HEPA filter.
Even with your explanation,it seems the hose is clogged.Try taking the hose off,then blow through it or pour water through it.If this doesn't do it,make sure the suction canals are going to the proper areas. ... Eureka 2900A / 2901A Contour Bagged Upright Vacuum
Eureka Bravo with new belt & bag suddenly won't start. I replaced a very worn and slack belt with a new one, vacuum then ran for maybe 20 seconds then shut off and now won't restart at all. Bag was also changed at same time. Is there a fuse, maybe? New belt too tight? Thanks
... Eureka Bravo II Bagged Upright Vacuum
Eureka Model C2094-Type GW Vacuum 1 Bags-Belt- Beater Roller or bristles that go on roller-light bulb Vacuum 2 Bags-Belt-Beater Roller-Bulb-Plastic frame the motor bolts on-Metal holder the handle go in that lets the handle move up and down
... Eureka Vacuums
Hoover Bagless Hello, My Hoover bag less (Model U5280-900) is not picking up dirt like it should. The brush roll is spinning fine, but the bristles on it are only about one quarter inch long. I am wondering how long they should be. The vacuum is quite a few years old. Do you think it is time to replace the brush roll. Could you email me at [email protected] about this topic. The product bar below did not contain my model no. The correct model no. is above in my message. Thanks
If the belt is more than six months old then change it even if it is not broken. then replace your filters if that doesnt work than check the hoses for a clog drop a marble down them and make sure it comes out. ... Hoover U5753-900 WindTunnel Bagless Upright Vacuum
I have a Eureka 4800 series the Boss upright with a bag and Hepa filter. I love it! I was just vacuuming with the hose part and all was well and then suddenly the lower brush came on and a "burning" smell followed. Thought it was the belt so my husband was going to put on the new belt which I had on hand! When he turned it over, the "bar" that holds the belt looks as though it "shot through" the plastic side of the housing on the vacuum. There is melted plastic on the outside of the vacuum and o
I had the same problem. Take out the old belt if possible. Remove the 4 screws inside the filter and the 3 on the front of that housing. pull out the foam around the motor. carefully pull out the suction tube that is press fit against the motor. ... Eureka 4874 Bagged Upright Vacuum
My Kirby vacuum is a G100 upright. It has no suction. It has been cleaned and the bag is empty (new bag). My mother-in-law bought the same kind and hers is doing the same thing. It has no suction and won't pick up anything. Thank you, Rachel Souza - [email protected]
... Kirby Vacuums
Aerus/Electrolus canister vacuum model C152C turns off and full bag indicator lights even with new bag.
Here is a list of things that could cause this, and how to check and/or "fix" them.\015\012\015\012First, turn dial on top of vacuum counter-clockwise so the smallest dot lines up with the arro ... Vacuums
No rotation dirt not getting picked up - Eureka Altima Upright Vacuum Model 2996AVS Vacuum
Replace the belt. ... Eureka Altima Upright Vacuum Model 2996AVS Vacuum
Eureka model 4870 g2 belt replacement - Eureka Smartvac 4870 Bagged Upright Vacuum
... Eureka Smartvac 4870 Bagged Upright Vacuum
My vacuum is making a whistling sound and when I turn it off it momentarily gets louder and makes a honking sound. The vacuum is a Kenmore canister vac model # 116.27814. It has a new bag and filters.
... Kenmore 27814 Bagged Canister Vacuum
My new Kenmoore Powermate 116 canister has poor suction. I have no pets and light dust. Its not picking up small particles on the wood floor with the floor attachment. When I put my hand to the suction it feels weak. Cleared hose and changed bag. Using again, same issues. This should not be happening with a new vacuum. Is it a bad design in the elbow joint of the hose? I want to return this!!!!
First of all disassemble the handle and hose as much as possible and examine the inside. Make sure there is not any significant debris lodged in the hose somewhere like a plastic bag or something.\015\012\015\012Also check at the top of t ... Kenmore 23912 Progressive PowerMate Bagged Canister Vacuum
Vacuum has new bag but won't pick up dirt. Cleaned flat filter and it made it worse. Do I need to replace rectangular filter or can I clean it. If so , how? If not, do I need to take it in for repair, ir should I get new parts? Thanks!
It's clogged somewhere. Disconnect the hoses where you can and check for obstructions. Run a coat hanger down the hose if you need to to clear the obstruction. ... Kenmore 31913 Progressive Direct Drive Bagged Upright Vacuum
Unbeknownst to me, someone took the bag out of my Kenmore Progressive vacuum and failed to replace it. I have been vacuuming without a bag for months, and today the vacuum stopped sucking. When I opened up the front to replace the bag, tons of dirt and dust came pouring out. I thoroughly cleaned the vacuum, put in a new bag, but still no sucking power. Just dust coming from the rear vents where one of the filters is. Is the vacuum ruined, or is it a simple solution of buying a new filter?
Sounds like you need to buy a new motor. All that grit and dust will ruin a motor and I'm surprised it lasted as long as it did.\015\012This is where a vacuum that won't run without a bag would have been nice. (Aerus for one) ... Kenmore 31913 Progressive Direct Drive Bagged Upright Vacuum
Eureka 4331 (Boss Lite) vacuum doesn't pick up dirt anymore
... Eureka Lite 4331 Bagged Upright Vacuum
My oreck vacuum cleaner won't **** or pick up anything? Any ideas what it is? I have a new bag on it.
If the motor is running it prob needs the filter to be cleaned... does it have a rolling brush? is it turning? as maybe the drive belt has snaped ... Oreck XL2200 Bagged Upright Vacuum
Hi, I have a Eureka model #4472 does have a bag. The power switch would only go on if I held the vacuum handle almost to the floor and now it doesn't go on at all. We already paid to get it fixed once already. Please help
... Eureka 4472 Vacuum
My Oreck XL 9100HA started smoking (white smoke) when I vacuumed. There is a burning rubber smell. How do I check/change (if appropriate) the belt? I have no User manual, nor can I locate one on the Oreck site. The bag is a new one. The vaccuum had been picking up, though not at its best strength.
It sounds like the belt has been damaged. You can get another belt from yoru local Oreck store. You can even take it in to the store to show them what happened. Purchase another belt and replace it. (It was very easy when I did this, so hopefully ... Oreck XL Ultra Bagged Upright Vacuum
My eureka model 5892 vacuums up the dirt and roller is working but it makes alot of dust and throws back what it picked up
It needs a thorough cleaning - \015\012Copy and paste the following into your browser....\015\012http://www.eureka.com/service/manuals/74227.pdf ... Vacuums
I have a eureka the boss vacuum it wont pick up. I cleaned out the tubes the belt is good. the tubes are clear. What else can I do?The bag is only 1/4 full
... Eureka Vacuums
I have Optima, 12amp Eureka vacuum, Model 431, AXZ type and the extension hose for cleaning corners and edges --the plastic part that the attachments fit into has a piece broken off and tools don;t fit anymore. It looks like the hose attachment can be replaced--can it be and if so--where can I get a new hose attachment. It seems it is cheaply made of plastic and really shouldn't have broken a piece off.
... Eureka 431A Optima Bagless Upright Vacuum
I have an old (50s) GE vacuum canister model VIIVTI made in Bridgeport, and I don't know what kind of bag it uses. It looks like a Eureka, but it's definitely GE.
... GE Vacuums
My eureka vacuum won't suction and starts to smoke when I try to use it. It sounds like it is suctioning when I first turn it on, but after about 20 seconds it begins to smell like burning and does not suction at all. I have tried cleaning and unclogging the filter and everything. It's bagless so I don't need a new bag.
The problem is that your belt is stretched and worn. This causes that burning smell and it also causes the vacuum to not pick up well. You need to replace the belt. Here is the belt you need and the manual with instructions: ... Eureka Altima Upright Vacuum Model 2996AVS Vacuum


text:
After his Karnataka counterpart, BS Yeddyurappa has been submerged in land scams and other accusations, Reddy wants to play it safe and avoid prying media eyes. He also wants to make sure he steers clear of any controversy and is currently taking a breather after the Telengana and fasting spells in his tenure.
Kiran Kumar Reddy owns agricultural lands in Kodigehalli. The land up for sale was purchased much before his chief-ministership The land has controversy written all over it as the property is disputed and reports of earlier transactions being fraudulent has cropped up. The property is an Inam land belonging to a Scheduled Caste family and laws are strict about such property transactions.
The current occupants of the land, retired ITI employee H Venkatesha and family cultivated various cereals there till August. They realised one fine day that a compound wall had come up and security installed there 24/7. Venkatesha who is fighting litigation to claim ownership of the land now faces a powerful opposition in the form of none other than the Andhra Pradesh CM.
Venkatesh had inherited the property from his forefathers in 1983 who was given the land under the Inam Abolition Act by the state government. Inam lands are given to the SC/ST class who are involved in menial jobs. The land could not be engaged and was in a lock-in for 15 years that meant that it could not be sold or alienated till 1998.
Andhra CM has found himself walking into the eye of the controversy with the apparent "illegal transaction". The plot was split in 5 and deeds made accordingly on a cost of Rs 30 lakh. With land appreciation sky-rocketing, the CM's men have spread the word in and around KR Puram that the CM's land is on sale. The land is valued at Rs 2 crore per acre currently.
OneIndia News


text:
To my werewolf
You know who you are and I don't know if you'll see this or not, but its just some things I wish I had the balls to say to your face if I'm honest. Now I don't know where to start...
Firstly, I owe you my life. Hands down, you saved me from the downwards spiral that I got caught in. I'll never forget the nights you spent making sure I was okay, making sure I would still be there in the morning. Even now, you remain the only person to make me laugh while my heart was breaking. And for the simple fact you never fail to make me smile, I will always be in your debt.
Its taken me a while, but especially recently, I've come to realise just how lucky I am to have you. Despite what you might think of any situation, you always try to look out for me. No one else has ever done that for me, ever. You've seen me at my very worst and still think that I'm a decent person. I don't know if that makes you a nutter or a saint, either way, I honestly can't imagine life without you. Of all the people in my life, you are the only person I would say I'd trust with anything, 100% and know you won't let me down. You are the only person who seems to completely understand who I am and what I'm about and thats something so incredibly rare, I still need to pinch myself to remind me its true.
Your trust, your love and your friendship is something I treasure more than anything else. If I ended up broke, with no home, starving and in the worst possible situation, I'd still feel like the richest person in the Universe so long as I had you there. You mean the absolute world to me. Losing some people might be almost unbearably painful, but losing you would literally kill me. Even though, strictly speaking, we haven't known each other long, in that short time, you've become an essential part of my life. I literally feel like I can't function without you some days.
And the thing is, you treat me like gold despite what I dump on you sometimes. You treat me so much better than I deserve at the best of times. Where a lot of people will believe when I say I'm fine, you don't when you can see I'm not. And you always see right through me. Even if I sometimes hold it back from you, you always see when things aren't good. You read me like a book. And you always know the right thing to say, but you still aren't afraid to be honest with me. Never stop being honest with me. Never be afraid to say something that might be hard for me to hear. Hearing it from you would be easier than finding out the hard way. Yes, I am pig-headed and stubborn and don't listen a lot of the time. But I never ignore what you say, even if it seems like it. Apart from anything else, you're impossible to ignore.
And one day, I know that the world will see that. They will see what a truly incredible person you are. Some people see a little, but I'm not sure they understand it just yet. I'm not claiming I do, just saying that one day, it won't just be me that says you deserve greatness. You weren't meant for an anonymous life. You're destined for great things and I feel proud and honoured that I can call you my best friend. I hope that I can for a very long time to come.
Honestly, I don't know what you would make of this.. For some reason, I can't say it to your face, though most of it you already know. Yes, I know that makes me an idiot and a coward-but I never claimed to be anything much really. But you saw something in me that very few other people did. And you were the only person willing to keep fighting for it time and time again. The fights are over now, I promise. I won't put you through that again. You deserve better and I will be better.
All I can say is that no matter what you have to say, no matter what you have done, no matter what you need, I will be there for you as best I can be. Even if all I can do is give you a hug, I will be there right by your side. I believe in you. I have faith in you and I know you will achieve your dreams. I can believe in you enough for the two of us. I might not be strong for myself, but I'll be stronger than diamond for you.
Really, all of that can be summed up in one promise. Semper fidelis. You taught me that and its something that will leave its mark for eternity on me.
All my love, now and always,
Your big sister x


text:
I was inspired by the previous post to research the Rex-Acme marque, since Bernard Hieatt was racing such a machine at Brooklands. Rex-Acme motorcycles were renowned for a short period in the 1920's (say '24-28) for producing some of the most formidable racing motorcycles in England. Lots of success at Brooklands and in the Isle of Man (courtesy of Wal Handley) meant that this tiny manufacturer had great stature in the Vintage period, and the machines are now terribly rare and coveted.
Such was their racing pedigree, they used as their logo the Isle of Man triskelion on their logo (the Latin motto for the symbol - quocunque jeceris stabit; 'wherever you throw me, I stand' - the image is used in Sicily as well. Wiki claims a Celtic origin, but surely the invading Romans had a hand in it's design - triskelion is a Greek word anyway!).
I've seen a few at events around the world (although never in the USA), and none look remotely similar, such was the bespoke nature of their build, combined with years of mechanical changes for competition.
The top two pix are from the Banbury Run in 2007; the bike is a 1927 350cc Rex-Acme with a Blackburne engine (as all the racing bikes seem to have), belonging to Christopher Pierce. I note the Velocette positive-stop shifting mechanism on the gearbox; I think this bike used to belong to Brian Wooley, former editor of the Classic Motorcycle. Brian's bike had the same scalloped Velocette front brake as well. There is an article in Classic Bike from March 1985 which shows this machine, 23 years ago, in Brian's hands, reminding us that we are only custodians of these machines.
Next pic is from British Only; it's a 1928 500cc Blackburne-engined model, which was previously raced in Austria at some point; take a gander at the 'before' pic, which is pretty daunting. To be honest, the bike isn't well restored at all, and is going to need a better job done, with correct inverted levers and properly-fitting mudguards, and some decent paint and plating. The bike is too good to have a half-hearted job!
The 'before' pic shows an interesting feature of the Blackburne engines - their external flywheel. I'm not certain why they used this, as there is a complete set of flywheels inside the crankcase, but I understand that these engines are exceptionally smooth running, so perhaps the outside wheel dampens vibration. Another odd detail is the use of a crowded-roller drive-side main bearing, and a plain bush on the timing-side main... not a recipe to inspire confidence, but it obviously works well here.
The bottom two pix show a Rex at the Brooklands Reunion meeting in 2005, which has a similar early-style saddle tank as above. These first saddle tanks tended to be slab-sided and kind of squared-off, and were usually used for long-distance racing at Brooklands etc. You can see similar designs used by AJS and Sunbeam around this same 1926-28 period (George Cohen has such on his Norton sidecar outfit, too). It looks like this machine is ridden as well, as the owner has bothered to put a small silencer on the exhaust pipe. The carb is a later TT Amal, which I'm sure works better than the original Type 26 Amal track carb, which had no needle and was meant for full-throttle work only.
Here is a youtube video of a Rex-Acme in action! This is Martyn Adams with his 350cc ca '26 Rex.
I'm still researching Blackburne engines!
Here is a list of published articles I've found on Rex-Acme; contact me if you find more, and I'll add them to the list:
Classic Bike, Mar '85
Classic Motorcycle, Aug '90
Classic Motorcycle, Nov '93
Classic Motorcycle, Nov '04
'Historic Racing Motorcycles', J Griffith, '63, Temple Press
Plus, Rick Parkington has been chronicling an affair with his own Rex.
Wednesday, January 23, 2008
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