Lets say CE1 and CE2 are doing L2VPN and all hops between PE1, P1,P2 and PE2 have more than one equal cost paths (ECMP).
I am trying to ascertain a way of knowing what path the EoMPLS traffic would take inside the SP core.
Some vendors say the way the hashing works is that if a PE finds its got more than one path to the egress PE, it would do hashing based on src/dst MAC and in other cases if a P device finds its got more than one path to egress PE, it would do hashing based on VC-label.
In either case, lets say we know what hashing method the P or PE device is using, obviously we would need an easier method to determine what path a pseudowire would take inside the provider network - Again, some vendors use what is called a "pseudowire traceroute" to determine this path. A pre-requisite of this is that at the time of setting up of the PW, the control word needs to be turned on.
I am looking for more knowledge on whether someone knows how the pseudowire traceroute would work and the process behind the PW traceroute which uses the control word ? more like how we know a normal traceroute works is through UDP pakcets with incremenyting TTL... and so forth
For L3VPN, load-balancing is based on the IP source and destination addresses of the packet to find which path will be chosen you can use the following commands:
On PE: IP2IP: sh ip cef exact-route IP2tag: sh ip cef vrf exact-route Note: use sh mls cef instead of sh ip cef for 7600 platform On P (12.0S only) : tag2tag: sh mpls forwarding-table labels exact-path ipv4
For L2PVN, load-balancing is based only on the VC label.
On PE: show mpls l2transport vc detail
On P (XR only):
sh mpls forwarding exact-route label bottom-label