I had difficulty finding an IOS version that would run MPLS on my 2611XM routers with 96MB RAM and 32MB flash, so thought I’d post the version that I’ve had success with. The image that worked successfully was c2600-jk9o3s-mz.123-24.bin. The routers are connected together on Fa0/1 on each router. Fa0/0 goes up to an ESXI box running two IOS XRv PE routers. It’s interesting to watch modern MPLS applications run over these old routers. Due to the age of the…
Unicast flooding problems, usually associated with switched networks, can also impact VPLS. If traffic is forwarded asymmetrically through a VPLS instance, unicast flooding of unknown frames can occur. I’ll step through a scenario where this could happen. I set a LAB up with two CSR 1000V routers acting as PE routers, providing a VPLS instance. GNS3 was used to run the IOS routers acting as CE and C routers. In this scenario we could imagine that CE3 and CE4 are…
The purpose of the MPLS MRU (Maximum Receive Unit) is to indicate the maximum size of a packet, including MPLS labels, that the local router router can forward without fragmenting. MRU is only locally significant. If an incoming packet belonging to a particular FEC (Forwarding Equivalence Class) exceeds the MRU calculated for that FEC, the packet will require fragmentation prior to it being transmitted on the outgoing interface. The MRU for each FEC varies depending on the MTU of the…