Lsp Selection; Layer-2 Vpn Domains; Mac Learning - Extreme Networks BlackDiamond 6800 MPLS Installation And User Manual

Configuring MPLS Layer-2 VPNs

LSP Selection

By default, a TLS tunnel will use any available LSP to the TLS tunnel endpoint IP
address. If there are multiple equal cost LSPs, the TLS tunnel is load shared across up to
four LSPs. Optionally, a TLS tunnel can be configured to use a specific RSVP-TE LSP. If
the RSVP-TE LSP metric is set higher than its underlying IGP metric, the LSP is not
used to forward normal routed IP and is only used to forward TLS VLAN traffic.

Layer-2 VPN Domains

Layer-2 VPN domains can be created by configuring multiple TLS tunnels for a single
VLAN. Each TLS tunnel connects the local TLS VLAN instance to an egress LER, to
form a Layer-2 VPN domain. Integrated MAC caching is supported on the MPLS
module. This allows the switch to learn MAC addresses of devices that are located on
the TLS tunnel egress LER. If the destination MAC address is known, the packet is
forwarded into the learned TLS tunnel or onto the local VLAN. If the destination MAC
is unknown, or the packet is a broadcast or multicast packet, the packet can be flooded
in one of two configurable modes.
• Full Mesh
Packets received from the local VLAN are flooded into all TLS tunnels. Packets
received from a TLS tunnel are flooded onto the local VLAN only.
• Hub-and-spoke
Packets received from the local VLAN are flooded into all TLS tunnels. Packets
received from a TLS tunnel are flooded onto the local VLAN and into all other TLS
tunnels.

MAC Learning

Learned MAC addresses are associated with the TLS tunnel from which the packet was
received. The learned MAC address is always inserted into the FDB as though it was
learned on the local VLAN (and not the VLAN identified in the dot1q tag in the
received TLS tunnel packet). MAC addresses learned from TLS tunnels use the same
FDB aging timers as those MAC addresses learned on Ethernet interfaces. Any MAC
address associated with a TLS tunnel is automatically cleared from the FDB when the
VC label for the TLS tunnel is withdrawn.
MAC addresses may appear to move between TLS tunnels. This can occur for various
legitimate reasons. The FDB aging timers will clear stale MAC entries, but in certain
7-4 MPLS Module Installation and User Guide