[c-nsp] Cisco 7600 vlan issue

[Ian Cox]

Saku Ytti wrote:
> On (2008-11-30 19:28 -0500), Julio Arruda wrote:
> 
>> I was under impression the L3 forwarding and the L2 forwarding was done  
>> by the same engine, in the PFC card(s) ? and behind it, the EARL for the  
>> lookup and the rewriting of the header info (mac rewrite, dec ttl and  
>> goes on) ?
> 
> Inside PFC/EARL you have Tycho for L3 and Superman for L2. Or 
> one cost reduced version called Supertycho (with bus chip functionality
> separated to dedicated chip called Kuma) in 3C and up (prolly
> nexus too then).

Nexus 7000 run a newer generation of the PFCx ASIC which allows for vlan
uniqueness per port.


Ian

> 
>> That is how Nortel 8600 (and earlier gen, rapidcity-legacy) did the  
>> work, the same lookup engine would do l2 and l3, so I may be messing up  
>> things in my mind :-), in a little more distributed fashion (more like 
>> DFCs)
> 
> Dunno if this true, prolly depends how deep inside the die you look.
> Also not sure what relevance there is if L2/L3 lookup is in one engine
> or several engines. In my mind at least it's not advantage or disadvantage
> for consumer, except for the fewer dies you have, the cheaper
> it is to produce (better yields) and less power will probably
> be dissimulated as heat.
>