If the destination address is unknown, or is a broadcast or multicast address, the frame is flooded to all ports associated with the virtual bridge.
Therefore in operation, VPLS offers the same connectivity experienced if a device were attached to an Ethernet switch by linking virtual switch instances (VSIs) using MPLS pseudowires to form an "emulated" Ethernet switch.Ĭompared to traditional LAN switching technologies, VPLS is also more flexible in its geographic scaling, so that Customer Edge (CE) sites may be within the same metropolitan domain, or may be geographically dispersed on a regional or national basis. The increasing availability of Ethernet-based multipoint service architectures from service providers, for both L2 VPN and 元 VPN services, is resulting in a growing number of enterprises transitioning their WANs to these multipoint services and VPLS is playing an increasingly important role in this transition. As highlighted in Figure 3-1, a VFI is linked (with a 1:1 mapping) to a Switch Virtual Interface (SVI).
This is done for all the VLANs that need to be extended across the VPLS domain. The virtual Port Channel (vPC) functionality allows establishing port channel distributed across two devices, allowing redundant yet loop-free topology. Currently, vPC technology is offered on the Nexus 7000 and Nexus 5000 platforms.Ĭompared to traditional STP-based environments, vPC allows redundant paths between a downstream device and its two upstream neighbors. The deployment of these Multi-Chassis EtherChannel (MCEC) connections between the vPC peers and the downstream devices provides the following benefits: With STP, the port channel is a single logical link that allows for building Layer 2 topologies that offer redundant paths without STP blocking redundant links. Removes dependence on STP for link recovery.
Doubles effective bandwidth by utilizing all MEC links.
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