Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 357)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 333
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LDP ECMP LER
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LDP ECMP LER
Glossary
TABLE 43 Glossary
Term Meaning
CAM Hardware Routing Table
CAM2PRAM Indirection pointer to PRAM table, also has no ECMP paths
ECMP Equal Cost Multi Path
IPoMPLS IPv4 (shortcuts) over MPLS tunnels
L3VPN Layer-3 VPN routes
LER Label Edge Router
PRAM Next-hop information table
RTM RTM module on MP
Overview
The LDP ECMP LER feature provides the capability to create LDP tunnels with up to eight paths.
These tunnels can be used by applications like IP over MPLS and L3VPN to transport IPv4 and IPv6
traffic. The traffic sent over the tunnel is load-balanced across all the paths based on a hashing
algorithm. The algorithm takes into account the information from the packets such as MAC
address, IP address, TCP and UDP ports.
Configuration considerations
1. By default, LDP ECMP is disabled on an LER or LSR.
2. It is possible to configure LDP ECMP through the command line. The moment the configuration
is done, for all tunnels for which the router is acting as ingress, changes are made to compute
ECMP paths. The same command is already used to compute the ECMP paths for LSPs
transiting the router (already existing functionality works without change). Information from
RTM is used to get the set of equal cost paths.
3. The maximum number of paths used by LDP ECMP ingress is same as transit. The default is 1.
4. When MPLS OAM ping or traceroute is done on a LDP tunnel, MPLS echo request is sent out on
the first path of the tunnel. Optionally, you can choose which path to send the request by
specifying the next-hop IP address.
5. When LDP graceful restart is enabled and VPLS uses LDP tunnel for its transport, MPLS makes
sure that the path used to carry VPLS traffic remains unchanged after MP failover and there is
no traffic loss observed during the failover.
6. L2VPN application does not have support for LDP ECMP at LER. L2VPN can still use the LDP
tunnel; however, all L2VPN traffic is sent out on a single path.
7. ECMP routes cannot have a combination of IP nexthops and MPLS nexthops.
8. Individual paths of a LDP ECMP tunnel can ONLY have outgoing interfaces of type physical, VE
or LAG. LDP over GRE or LDP over RSVP ingress functionality is not supported.