b-racks per rack Control Duplicated network element controller in hot mirroring configuration Management ITU ASON I-NNI OIF UNI 1.0, OIF E-NNI 1.0 ASON compatible network manager Switch Fabric SDH fabric strictly Hot standby Mixed time and space nonblocking duplication domain Switch Fabric Options SDH (STM 1 capacity) 160 Gbit/s 320 Gbit/s 640 Gbit/s Ethernet switch 20 Gbit/s 30 Gbit/s 40 Gbit/s Interfaces STM-1, STM-4 SFP modules Gray optical 4 ports STM-16 SFP modules Gray optical 4 ports STM-64 XFP modules Gray optical 1 port STM 128 Embedded TXT Gray optics 1 port SFP modules Gray optical 16 ports 10GbE XFP modules Gray optical 1 port Switching Systems: Architecture and Performances TABLE 7.4 Summary of the Feature List of a Practical MSPP/MSTP MSPP/MSTP Platform Mechanic Option 1 One sub-rack compatible with ETSI 300 119 rack; 16 unit maximum Option 2 Compact rack proprietary: compatible with ETSIETSI 300 119 mounting system Control Duplicated network element controller in hot mirroring configuration Management Q interface Local craft and remote management OSI IS-IS and TCP-IP OSPF Switch Fabric Strictly nonblocking VC12 based Hot standby duplication Mixed time and space domain Switch Fabric Options SDH (STM 1 capacity) 64 X 64 128 x 128 384 X 384 Ethernet switch 5 Gbit/s 7 Gbit/s 20 Gbit/s Interfaces STM-1 16 ports Electrical 1:N card protection supported STM-1, STM-4 SFP modules Gray optical 4 ports STM-16 SFP modules Gray optical 4 ports STM-64 XFP modules Gray optical 1 port STM-64 Embedded TXT DWDM optical (50 and 2 ports 100 GHz) STM 16 SFP modules CWDM-eight channels 2 ports available Fast Ethernet SFP module Gray optical 22 ports Fast Ethernet SFP electrical Electrical 22 ports SFP modules Gray optical 16 ports 7.8 Packet Switching at MPLS and IP Layers: Routers This section is devoted to the architecture of the routers. Routers were born as Layer 3 switches, that is, switches that implement switching at the IP layer using a datagram like architecture [1]. The evolution of the data network has brough