[c-nsp] Sup32 TCAM limit

[Phil Bedard]

They are a good fit for Enterprise IP/MPLS networks which may not have  
full routes, since they generally default to a firewall somewhere for  
that.  Also if you need something like a cheaper EoMPLS aggregation  
box they fit that need as well, or as relatively cheap P LSR.  	

Phil

On Jun 26, 2008, at 10:38 PM, The Father wrote:

> Man, that's just swell.  We recently ran into this same issue after  
> enabling MPLS on our SUP32s (core and gateways).  I always had a  
> feeling that they were limited but didn't really realize it until we  
> started seeing the EXCEPTION messages.  I'm hoping they can last  
> another year or so and then replace them with either GSRs or  
> ASR1000s.....the gateways that is....the core I would hope to have  
> BGP-less and possibly free up some routes with additional OSPF  
> enhancements.
>
> So if these SUP32s are pretty much useless for holding the full  
> internet tables, what good are they?  PEs sometimes have full  
> Internet routes so where would they fit in?
>
> Jose
>
>
> Phil Bedard wrote:
>> Like you said, the limit is around 250k routes.  The box will  
>> through a FIB EXCEPTION when it reaches that limit.  It will remove  
>> the shortest-match prefixes from the TCAM and install a default  
>> route with a PUNT adjacency, which punts traffic to the MSFC.  You  
>> don't really want to software switch anything through the SUP32...
>>
>> I don't know anyone that uses the SUP32 to carry a full Internet  
>> table.
>>
>> Phil
>>
>> On Jun 26, 2008, at 3:48 AM, Gregoire Huet wrote:
>>
>>> Hello
>>>
>>> Reading the previous threads on this topic, I have understood that  
>>> the TCAM
>>> size would limit the number of routes on the Sup32 supervisor  
>>> blade to 249k.
>>>
>>> What I do not understand is what would happen to the routes being  
>>> inserted
>>> above this limit. Would such routes be 'soft' routed ? Is there  
>>> also a treshold for
>>>
>>> I would appreciate to know your experience with this blade and the  
>>> increasing
>>> number of public IPv4 routes.
>>>
>>> Best regards
>>>
>>> Greg
>>>
>>>
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>