[c-nsp] WS-X6148-GE-TX over subscription

Oliver Boehmer (oboehmer) oboehmer at cisco.com
Wed Feb 8 01:40:29 EST 2006

Bas <> wrote on Wednesday, February 08, 2006 3:09 AM:

> Hi All,
> I know the WS-X6148-GE-TX has "only" six 1Gbit ASICs And thus can
> handle 1Gbit traffic per 8 Interfaces.
> My question is:
> How is this oversubscribtion handled by the WS-X6148-GE-TX?
> Is it 1Gbit/s per eight ports?
> Of will all traffic be balanced over the ASIC's?
> If the first is the case... is it ports 1<-->8 and 9 <-->16 etc etc
> per asic? or is some other algorithm used?

Basically we have one ASIC in front of each block of 8 ports, 1-8, 9-16,
etc. Those ASICs (6 of them) have a 1Gbit connection each to the bus
(via Pinnacle ASICs). So the group of 8 ports is limited to 1Gbit/sec.
One addtl. caveat with this architecture: If one of the ports is heavily
oversubscribed (i.e. we need to queue pkts), you will likely see
increased latency on the other ports within the "block", as there is
only a single queue for all 8 ports within the block. 


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