[c-nsp] 6500 SUP720 High Latency and Jitter issues

Troy Davis troy at nack.net
Wed May 25 16:33:14 EDT 2005


On Wed, May 25, 2005 at 12:32:09PM -0700, matthew zeier <mrz at intelenet.net> wrote:

> > As Ian Cox said on this list, turning a 7600 into a 7200 (by forcing
> > it do to software forwarding) is never a good idea.  But it's easy to
> > do so by accident, and hard to find out after the fact why it
> > happened.
> 
> How is that accidentally done?  Do ACLs force software forwarding?

I've seen some Sup2/MSFC2s running in native mode where the MSFC2 was
upgraded to 256 MB for full BGP routes but the Sup only has 128 MB - not
enough for the resulting CEF table.

Packet forwarding still functions, and many folks never touch the Sup
after converting to native mode.  To check, on the MSFC, attach to the Sup
CLI with "attach 1" (assuming it's in slot 1) and run "show ip cef" -
you'll either see CEF table entries or "CEF not running."

Most ACLs are hardware-accelerated, with a few restrictions.  See
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/122sx/swcg/acl.htm

Troy


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