[c-nsp] "show platform hardware capacity" shows sup720-3b FIB tableat 98%

Peter Kranz pkranz at unwiredltd.com
Fri Jul 21 12:27:22 EDT 2006


I've been told that the 256k route limit on the 3b was bogus, would be
interested in any feedback on that, since if it's a real limit it makes the
3b a no go for anyone getting full routes now. 

Peter Kranz
Founder/CEO - Unwired Ltd
www.UnwiredLtd.com
Desk: 510-868-1614 x100
Mobile: 510-207-0000
Fax: 510-217-6031
pkranz at unwiredltd.com 


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Darrell Root
Sent: Thursday, July 20, 2006 10:00 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] "show platform hardware capacity" shows sup720-3b FIB
tableat 98%


Apologies if this is a rerun.  I tried to search for dups.  I figured a
warning was timely.

There's a cool new command in 12.2(18)SXF: "show platform hardware capacity"

It shows the capacity of all resources on the box.  FIB tables.   
TCAM.  Flash.  Tons of
stuff you never heard of.

Until we upgraded to a sup720-3bxl (very very recently), our sup720-3b with
full internet routes showed the following:

L3 Forwarding Resources
              FIB TCAM usage:                     Total         
Used       %Used
                   72 bits (IPv4, MPLS, EoM)     196608       
192900         98%
                  144 bits (IP mcast, IPv6)       32768            
5          1%

                      detail:      Protocol                     
Used       %Used
                                   IPv4                       
192900         98%
                                   MPLS                            
0          0%
                                   EoM                             
0          0%

                                   IPv6                            
2          1%
                                   IPv4 mcast                      
3          1%
                                   IPv6 mcast                      
0          0%


So while the sup720-3b is advertised as being able to handle 256k routes, by
default it allocates 64k 32-bit entries to IPv6 and multicast, giving a
default IPv4 capacity of 196608 entries.  The Internet route table is almost
there.  At the current rate of growth we've got about a month.

I would assume that if we hit 100% that bad things would happen.  The cat6k
makes a pretty good 7200 when it forwards in software ;-)

A previous message on this list from Andrew Fort indicates:

> box#show mls cef maximum-routes
> FIB TCAM maximum routes :
> =======================
> Current :-
> -------
>  IPv4 + MPLS         - 192k (default)
>  IPv6 + IP Multicast - 32k (default)
>
> I know you can re-carve this ('mls cef maximum-routes ...'), which 
> obviously requires a reboot.


On a sup2 in hybrid mode "show polaris fibmgr usage" shows:


Total FIB entries:        262144
Allocated FIB entries:    193003
Free FIB entries:          69141
FIB entries used for IP ucast:  193002
FIB entries used for IPX     :       1
FIB entries used for IP mcast:       0

So I think my sup2 hybrids are ok.

Question: Are my sup2 native-ios boxes ok?  I can't figure out how to verify
my free FIB capacity on my 12.1E boxes.  Anyone know the magic command for
that?

Darrell Root
darrellroot at mac.com


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