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New Member


Guys I'm trying to make sense out of the attached Cisco Topology

My test environment consists of, various core (P)and distribution(PE) 7600?s (Sup720 without OSM, SIP-600, SPA). Access node consists of a Ethernet DSLAM (although kind of irrelevant at this point).

I?m focusing on layer 2 Access node ? Distribution (Active/backup) Redundancy (No aggregation layer) to two separate distribution PE?s. It seems as though its describing the classic triangular loop, completed by an inter-distribution EoMPLS PW. It then appears as if packets are been forwarded out of the layer 2 domain by an SVI on both distro?s, using HSRP as the floating gateway. The only issue is implementing PW on an interface and assigning an IP address. Unfortunately I cannot use VFI, though I?m not convinced this would help either. I cannot xconnect from an SVI either (due to restriction on non OSM, SPA modules). I?m guessing bridging using irb would be the only feasible solution (if it does work).

1) Am I way off?

2) Would VFI?s help in any way?

3) What would you suggest?

Any information related to this would be extremely useful. Many thanks in advance.

New Member



In which mode your 7600 operates? to support MPLS features it should be either PFC3B or PFC3BXL. If you have any OSM module it will operate MPLS over OSM as long as the peer IP address is learned through WAN interface, though its not recommended.

SIP-600 for 7600 comes with 3BXL but if there is any module with DFC3A the system will operate with common denominator which is PFC3A . so you can't run MPLS.

Normally you cannot have both the IP and L2MPLS configuration on the same interface. and on 7600 we are restricted to one VLAN database, (i.e. even you configure routed ports you cannot reuse the same VLAN on two different physical ports under subinterface)

Since we have to create another EoMPLS tunnel to outside we have to emulate a bridge domain and therefore we have to use VPLS where we have to configure VFI.

If we have to configure any first-hop redundancy protocol where we can configure...?