router vs switch on the access

axfalk · ‎09-04-2007

We're designing a network for a DR exercise and there's a question as to whether we need to have a router or a switch on the access. The network behind this device a flat network (1 vlan). Upstream from this device is an edge router that will do BGP and ipeFR. Can anybody please render an opinion on this?

Thanks.

Joseph W. Doherty · ‎09-04-2007

I'm of the opinion you meet requirements as simply as possible. With current equipment, for what you described (if I correctly understand), switches at the edge would be "simpler". However, some reasons for edge routing where you're not routing . . .

I've seen 1:1 edge routers used when using flow based hardware. The idea being that the edge router melts down before the next router upstream. Almost an external "control plane" protector.

Another reason, pseudo "distributed" processing. You expect the load imposed by edge QoS classification and marking or ACL processing could not be handled by the upstream router alone.

Some believe that such a design is easier to support with configurations on separate devices for QoS, ACLs and such.

As long as there's reason for using routers where you describe, then do so. Just be cautious of, "we don't know why, just would feel better". With the latter, analyze whether there's real reason for discomfort.