Hi Tim,
Sorry about that, assumed you were talking about ACL TCAM, but you
are referring to FIB TCAM.
In the scenario you mention, prefixes are installed in the FIB TCAM
on a first come first served basis. Packets not matching a prefix in
the FIB TCAM are punted to the CPU, but such traffic is heavily rate
limited (to protect the inband/CPU), so your routing will be
considerably hosed. Obviously we syslog such events.
As you probably know, n7k today has a 128K FIB TCAM, inadequate to
hold full routes anyway. Near-term we will have an XL card that holds
900K prefixes. In that case, you should not run out of FIB TCAM in
the case you describe, but as always, you should be sure not to
"miss" configuring route limits & filters to avoid issues, that's
clearly best practice.
Hope that helps,
Tim
At 09:31 AM 3/9/2010, Tim Durack clamored:
Good to know. I was actually thinking more along the lines of: BGP
peering, missing max-prefix, provider dumps 300k routes on me. What
does the N7K do? (Unfortunately I know what a 6500 does.)
Tim Stevenson, tstev...@cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Cisco Nexus 7000
Cisco - http://www.cisco.com
IP Phone: 408-526-6759
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