Chapter 14. Layer 2 Interworking and Local SwitchingLayer 2 Interworking technology overview Layer 2 Interworking case studies Layer 2 local switching with interworking Understanding advanced interworking and local switching
This chapter comprises important topics that are part of the Cisco Unified VPN Suite. The first part covers Layer 2 any-to-any pseudowires (also known as interworking [IW]), by which a pseudowire links two attachment circuits with different data-link layer protocols. You can provision Layer 2 any-to-any IW circuits using either Any Transport over MPLS (AToM) in Multiprotocol Label Switching (MPLS) packet-switched networks (PSNs) or Layer 2 Tunnel Protocol Version 3 (L2TPv3) in IP cores. This chapter covers both scenarios. The second part of this chapter details Layer 2 local switching, which allows you to switch Layer 2 packets between two interfaces within the same router. Layer 2 local switching is not a pseudowire technology per-say because pseudowire control plane signaling is not involved. However, local switching is considered part of the Layer 2 virtual private network (VPN) solution because operators who implement Layer 2 VPNs come across situations in which local switching is required. The final part of this chapter consists of a section about Layer 2 local switching with IW and a section on advanced topics that are related to Layer 2 IW and local switching. The case studies in this chapter explain how to configure and manage Layer 2 IW, Layer 2 local switching, and mixed Layer 2 IW plus local switching scenarios. They provide extensive examples using multiple attachment circuit technology combinations. |