Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 452)

428 Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide
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MPLS over GRE tunnel
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NOTE
Do not forward packets from one type of tunnel to another type of tunnel in XPP. Packets may not be
routed properly.
NOTE
MP switchover event may not be handled properly by MPLS or RSVP module. This may result in
inconsistent state for RSVP LSPs sessions. This could be fixed by adding support for RSVP Hello
feature.
LDP LSP over GRE tunnel
This feature works when a GRE tunnel connects two LDP LSP transit nodes and all LDP sessions
establish with each peer. Figure 50 shows four routers:
• Routers A and D represent the LDP LSP ingress and LDP LSP egress router.
• Routers B and C represent the LDP LSP transit and GRE ingress and egress points.
The LDP LSP ingress router passes a labeled packet to the GRE ingress and LDP LSP transit router
(1), which switches the label, encapsulates the packet and adds a GRE header (2). The packet goes
through the GRE tunnel (3). Next, the GRE egress and LDP LSP transit router removes the GRE
header, pops the label, and then forwards the packet to the LDP LSP egress router (4).
FIGURE 50 LDP LSP over GRE tunnel example
The letters A, B, C, and D in Figure 50 represent the names of the routers in the code configuration
example.
Redundant tunnels
The user can configure multiple GRE tunnels between two nodes using a loopback address or an
interface address as the source or destination address. In GRE tunnel configuration, the same
source and destination combination cannot be used for more than one GRE tunnel.