CSS ASR - Number of GE links

dan.shalinsky · ‎11-27-2007

Hi all:

Pretty basic question here. This Cisco doc (http://cisco.com/en/US/products/hw/contnetw/ps792/prod_bulletin09186a008007ca4c.html#wp41419) suggests the following CSS topology for ASR: "two links are used for redundant interswitch communication, two are used for redundant ingress, and two are used for redundant egress".

Can anyone clarify what they mean by ingress and egress, and whether this is in fact necessary.

If it matters, we use 1 client-side VLAN and 2 server-side VLAN's.

TIA,

-Dan

dan.shalinsky · ‎11-29-2007

Posting a follow-up answer to my question.

I believe that redundant links per chassis is not the optimum design because you would need to running spanning-tree. In fact, it's recommended to configure port-fast on the Catalyst port and disable bridging on the CSS altogether.

I also realized that trunk ports and spanning-tree are not necessarily required together so, in my case, my 2 server-side VLAN's can be trunked to a Catalyst using a single port.

Cheers,

Dan