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NPE-G1, CEF, WCCP, Subinterfaces, 802.1Q (dot1q) == SLOW WEB TRAFFIC

Hello all!

I have an interesting situation (or painful from my perspeective). I have a core router that is the center of a corporate network. We have four high use sites which were connected with T1 circuits. The remote sites have their own 2650 routers with 16 port ether-switch cards and content engines which are spoofing so the core can see individual workstation IPs. All routers run CEF and everything worked fine.

The sites' high bandwidth needs necessitated an upgrade to metro-ethernet. We are bringing in the four sites as dot1q VLANs on a 1gbs circuit to the core router. Each remote site gets a 100Mbs circuit with the necessary VLANs trunked to it. Sub-interfaces are used on the remote sites.

Initially, there were no gig ports in the core, so we brought the fiber for the metro-ethernet into a 3550 and passed of a routed subnet to the core. Everything worked fine.

[CoreRouter](Fe0/1)==(Gi0/12)[3550](Gi0/1)==dot1q==(Fa0/0.101)[2650](Fa1/0)==LAN

Later, we purchased an NPE-G1 card for our core 7206VXR router (IOS Enterprise 12.4 currerntly, tried 12.3 as well). We moved the metro-ether fiber to a gig port on the NPE-G1 and used sub-interfaces for the VLANs. NOW MY PROBLEMS START.

[CoreRouter](Gi0/1.10x)==dot1q==(Fa0/0.10x)[2650@Remote Sites x 4](Fa1/0)==LAN

Since attaching the sites to the NPE-G1 on the sub-interfaces, only the first sub-interface works with CEF. The other sites are noticeably degraded in their web traffic.

I assume this is some bizzare issue with subinterfaces, CEF and WCCP all interacting.

If I turn CEF off on the Core router and at the four metro ethernet sites, everything works fine. It seems to be on the core that the problem exists, and it's somehow related to the CEF and subinterfaces *and* maybe WCCP.

Thanks for any input anyone can give. This is a strange problem that has taken me a long time to identify, now to try to fix it!

David B. Hunter

Networking Specialist

South Bend Community School Corporation

South Bend, IN

dhunter@sbcsc.k12.in.us

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