[c-nsp] x6148 vs. x6548

[Arie Vayner (avayner)]

Guys,

Sorry, I pressed the send button to quickly. The 1Gig limit per etherchannel is still there even between slots for the x6148.

Arie

-----Original Message-----
From: Arie Vayner (avayner) 
Sent: Sunday, June 14, 2009 06:48
To: 'Geoffrey Pendery'; Bill Blackford
Cc: cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] x6148 vs. x6548

Geoffrey,

A small correction. The x6548 is an 8G card, but it has 2 fabric connections, so the limit would be 16G.

As long as you do not use the other 7 ports out of each 8 port group, each port group can give you 1G, but take into consideration that the x6148 is a classic card, so it has no fabric connections, and uses the shared bus.

In general the x6148 is not supposed to be a "core" card. It's for connecting low end desktops etc.

Arie

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Geoffrey Pendery
Sent: Friday, June 12, 2009 16:36
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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