[c-nsp] ASR1004 vs 7606(RSP720-CXL)

[Lincoln Dale]

On 27/11/2009, at 12:14 AM, Asbjorn Hojmark - Lists wrote:
>> If there's a 4 slot chassis in the 2nd generation then I could see
>> N7K and N5K / N4K as a possible end-to-end platform for L3/MPLS core,
>> L2/L3 aggregation, and L2 access.  And it would all run the same
>> software !!!  
> 
> Except, of cause, the N7K doesn't currently do MPLS and won't for
> another year, and when it does it will, as always, be released in
> fases. 
> 
> Also, Nexus is positioned for the DC, so there will always be lacking
> features when compared to the SP platforms.

certainly when we (Cisco) announced the Nexus platform, we wanted to be very specific in terms of where the Nexus portfolio is positioned - and more precisely where it is not - because NX-OS intentionally is not at parity with IOS, and the initial I/O modules weren't targeted at internet-sized h/w FIB.

that there isn't parity with IOS has both good points and bad points.
it rules out Nexus for some specific parts of networks.
but its also considered a good thing by others - Nexus & NX-OS reliability & availability are second to none, and characteristics such as forwarding remaining in a hardware path in all cases - are welcomed by many as a step forward.

fast forward to now from Nexus first release and some of the functionality enabled by Nexus and NX-OS are used by many folks outside of the 'strict' historic DC positioning


> 
> 'Don't send a switch to do a router's job'.

"routers" will always have deeper buffers, esoteric queueing structures and more functionality by virtue of the choice of software processing and/or programmable NPUs used.
however many folks today consider c6500/c7600 to be "router" platforms and they are fundamentally PFC3 based.

N7K M1 I/O forwarding engine is PFC4 which has all the capabilities of PFC3 + much more.
while its true that its not programmable in the sense of a NPU is, there is a lot of flexibility in its capabilities which will become apparent as there are subsequent NX-OS releases.

i think both have their places.
often it comes down to the price/port between a "router port" and a "switch port".
even with "L3 switches" the old adage of "switch where you can, route where you must" probably holds true.



cheers,

lincoln.