Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 559)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 535
53-1003031-02
Configuring MPLS VLLs
4
Specifying a VLL peer
The VLL peer is the PE router at the other end of the VLL. As part of VLL configuration, the user
specifies the IP address of the VLL peer.
Each PE router must have tunnel LSP reachability to its VLL peer. Tunnel LSP reachability is defined
as having at least one operational LSP tunnel with the destination (the LSPs “to” address)
matching the VLL peer’s IP address. An LSP terminating on the VLL peer but configured with a
different destination address would not be considered a match.
When a PE router does not have tunnel LSP reachability to its VLL peer, or when the remote VC
label is not yet available, packets from the local interface are discarded at the ingress PE router.
When the local interface is administratively disabled or goes down, a VC label withdraw message is
sent to the VLL peer.
By default, each PE router attempts to initiate an LDP session through extended discovery with its
VLL peer, when a session is not already established. The PE router also allocates a VC label from a
per-platform label range that is mapped to the local endpoint. Once the LDP session is established,
the locally assigned VC label, along with the VLL VC ID is advertised to the VLL peer in a
downstream-unsolicited manner. In a similar way, the PE also learns the remotely assigned VC label
from the VLL peer.
Alternatively, the user can configure static local and remote VC labels. In this case, no LDP session
is established between the VLL peers. Note that when the user makes use of static VC labels, the
user must configure them on both VLL peers manually.
The user specify the peer at the other end of the VLL by entering a command such as the following.
Brocade(config-mpls-vll)# vll-peer 192.168.2.100
Syntax: vll-peer ip-addr
The IP address of the peer must match that of a destination for a tunnel LSP configured on the
device.
Specifying a VLL endpoint
The endpoint of a VLL specifies what happens to packets exiting the VLL. The user set the endpoint
on the local PE router and this endpoint is mapped to a VC label. The VC label is advertised to the
remote PE router at the other end of the VLL through LDP. The remote PE router applies this label to
packets entering the VLL. When the packet reaches the end of the VLL through the MPLS uplink,
the local PE router checks the mapping between the VC label and the endpoint, removes the VC
label from the packet, and forwards the packet out the port specified as the endpoint.
All VLL endpoints can be dual-mode ports (tagged-untagged). An untagged endpoint port is
removed from the default VLAN and cannot be added back to the default VLAN. A VLL endpoint can
be tagged in multiple VLL and L2 VLANs and untagged in one other VLAN.
The Customer Edge (CE) device is connected to the PE router over an untagged, dual-tagged, or
single-tagged port.
• With a single-tagged port, each pair (port, VLAN ID) is identified as a unique endpoint, and the
packets are sent in tagged Ethernet format.