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MPLS and IP Routing
Multivendor Support for Indirect LSPs
To support the use of indirect LSPs, Extreme LSRs automatically advertise a label
mapping for a /32 LSP to its OSPF router ID (configured using the
config ospf
command).
routerid
Unfortunately, some MPLS implementations do not support indirect LSPs, and they
require that a label mapping be advertised for each FEC. If your MPLS network
includes equipment that does not support indirect LSPs, you must use configuration
commands to explicitly control the advertising of labels.
Optimized Forwarding of Non-MPLS IP Traffic
By default, IP packets received by the switch are passed to the MPLS module for IP
forwarding. This allows IP packets to be forwarded into LSPs. However, not all IP
routes necessarily have LSPs as their next hops. When the MPLS module finds that the
route for an IP packet has a normal IP next hop (no LSP to the destination IP address),
it sends the destination IP address of the packet to the MSM. The MSM then installs an
IP FDB entry for that IP address. From that point, until a routing change causes the IP
FDB entry to be deleted or the destination IP address becomes reachable via a newly
established LSP, IP packets for that IP address are forwarded by the switch without
going through the MPLS module.
This installation of IP FDB entries is disabled when Destination Sensitive Accounting is
enabled.
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MPLS Module Installation and User Guide
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