[c-nsp] x6148 vs. x6548

[Bill Blackford]

Your question is one of mine as well. I plan to from EC's across the 6548 and a 6516-GBIC (yes copper and fiber).

So does this essentially mean that every 6 ports has its own gig ASIC? So, I'd have to stagger like: 1/1, 1/7, 1/13, etc.?

Now, if what you're reporting is correct (I'm sure it is), then I'm not getting much more benefit going with the 6548. I know I can only get a standard MTU with this line card as well. I could consider the 6148A if I really wanted jumbo's, but that's not very high on my list of wants. The 6748 is out of budget range at this time unfortunately.

Thanks for your input.

-b

-----Original Message-----
From: gpendery at gmail.com [mailto:gpendery at gmail.com] On Behalf Of Geoffrey Pendery
Sent: Friday, June 12, 2009 6:36 AM
To: Bill Blackford
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] x6148 vs. x6548

Well, with the 6548, you're still going to be limited to 8 Gbps,
rather than 6 Gbps.  It's a CEF256 card, which means it has an 8 Gbps
fabric connection to the supervisor, instead of just sharing the 32
Gbps like the 6148 does.  So if you're looking to drive more than a
gig through an Etherchannel, it will do it, but only for a limited
number of them.  The 6748 would bump your bottleneck up to 40 Gbps.

I have a question of my own, since this subject has come up a time or
two - regarding the 6148's, the statement is made a couple times that
Etherchannel will get you port redundancy but no extra bandwidth,
since the ASIC is only a gig.  But if I distribute my channel across
two slots, say Gig 1/1 and Gig 2/1, does that get me around the gig
limit?  Or even Gig 1/1 and Gig 1/48, since it's separate ASICs?
Logic tells me yes, but I've heard the "1 gig limit" mentioned as if
it's a hard platform limitation, not just a result of a particular
bottleneck.  My instinctive behavior with channels is to span them
across blades anyway, to guard against blade failure....


-Geoff


On Thu, Jun 11, 2009 at 9:20 PM, Bill
Blackford<BBlackford at nwresd.k12.or.us> wrote:
> I've recently learned that the ws-x6148-ge-tx has 6 gig ASICs, one for every 8 ports thusly rendering this line card to a 8:1 oversubscription ratio. I've also learned that an etherchannel is limited to 1 gig, great for redundancy, but slow as all get up.
>
> I'm buying a ws-x6548-ge-tx in hope that it can do much better (I didn't have enough in my budget for a x6748). How does the 6548 compare to the 6148? I have a pair of shiny new sup720-3bxl's.
>
> Thank you for any insight from the field as Cisco's site seems best suited for the marketing of products.
>
> -b
>
> --
> Bill Blackford
> Senior Network Engineer
> Technology Systems Group
> Northwest Regional ESD
>
> my /home away from home
>
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