development of the Link Management Protocol (LMP) and optical exten- sions to Open Shortest Path First (OSPF). We will analyze the use of MPLS- based techniques for optical networks, but want to remind you once again that this technology is not a panacea for instant provisioning, particularly when you take the perspective of the end user. 7.2.2 Design Considerations OLS network design goals typically include the following: Flexible, scalable, and dynamically reconfigurable optical network Must not mandate that every node must have an IP stack or exclusively an overlay or peer architecture Must scale to accommodate large OLS (WDM) core networks Chapter 7 Enable the reuse of standard control plane protocols Routing and OSPF, signaling and RSVP, and the switching control interface and LSCP Paths set up and tear down according to MPLS label Integrated layer (IP/WDM) MPAS label-switched path (LSP) Figure 7-12 depicts a sample conceptual design. 8 Optical Label Switching Figure 7-12 Example of OLS node. Source: Gee-Kung Socket/CORBA Interface Network Control Chang, Optical (Management Interface) Internet Research, Sun Workstation Telcordia Technologies. Socket Interface (LSCP Messages) Network Element Switching Fabric Control Interface Edge Nodes Edge Nodes NT PC NT PC Switch NT PC NT PC LSC: Label Switch Controller SFC: Switching Fabric Controller Total Decision and Switching time is about 100 ns: 40 ns to acquire destination oriented label and priority information 20 ns to arbitrate control of the switch and output a new switch state 10 ns for LiNbO3 switch and 40 ns for the driver circuit All-Optical Networks 7.3 A Review of MPLS This section15 encapsulates the basic concepts of MPLS. The benefits of MPLS include the following: It has the capability to set performance characteristics for a class of traffic. It enables VPNs. Using MPLS, service providers can create IP tunnels throughout their network, without the need for encryption or end-user applications. It eliminates multiple layers. Most carriers employ an over