Alternatives to storm-control on Cat 6509.

Fri Aug 21 10:39:34 UTC 2009

Hello,

I have several Catalyst 6500 (Supervisor 32) aggregation switches with WS-X6148A-GE-TX and WS-X6148-GE-TX line cards.

These line cards do not support storm-control/broadcast suppression. This impacted us badly during a recent spanning tree event.

As it stands, we are at risk of overwhelming control planes with excess broadcast or multicast traffic, and I need to find alternative ways to protect these switches.

I have been researching STP enhancements, and control-plane policing in the following documents, and would appreciate advice from engineers who may have had to implement similar workarounds for storm-control in a service provider setting.

* Configuring Denial of Service Protection
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/dos.pdf

* Configuring Control Plane Policing
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/31sga/configuration/guide/cntl_pln.pdf

* Configuring Optional STP Features
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/31sga/configuration/guide/stp_enha.pdf

So, if we can't mitigate against STP events using storm-control or broadcast suppression, what might be the best combination of STP enhancements and control-plane policing?

For example, is it possible to rate-limit broadcast/multicast, STP and ARP on a per VLAN basis? If so, how?

Many thanks,

P

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Peter George
Lumison
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d: 0131 514 4022

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