RE: WS-X6148A-GE-TX performance question

["Holmes,David A" <dholmes () mwdh2o com>]

Cisco recommends both cards for access-layer use, principally as wiring
closet aggregation for desktop users. Cisco recommends 65xx or 67xx line
cards for backbone (read deterministic) connections, which means that
only 65xx devices with sup720s, or older switch fabric modules can be
used for deterministic network design. 

Note that Etherchannel limitations apply to both cards. Also running one
port in a group of 8 at line rate ( for example using that port as a
SPAN destination for a VLAN where traffic exceeds 1 Gbps) will cause
drops on the other ports in the group.

(see
http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a
0080094714.shtml ) 

-----Original Message-----
From: Crooks, Sam [mailto:Sam.Crooks () experian com] 
Sent: Thursday, September 10, 2009 2:59 PM
To: Bill Blackford; Scott Spencer
Cc: nanog () nanog org
Subject: RE: WS-X6148A-GE-TX performance question

the other difference between WS-X6148-GE-TX and WS-X6148A-GE-TX is the A
has better QoS queuing potential (more hardware queues available) and a
lower list price...

As I recall, there are 6 ethernet controllers with 8 ports on each...
(8:1 oversubscription among the adjacent ports in a port group which use
the same ethernet controller).

The card is a Classic card, so the whole card is limited to 32 Gbps to
the backplane, which given the oversubscription ratio, shouldn't be much
of an issue...



> -----Original Message-----
> From: Bill Blackford [mailto:bblackford () gmail com] 
> Sent: Thursday, September 10, 2009 4:40 PM
> To: Scott Spencer
> Cc: nanog () nanog org
> Subject: Re: WS-X6148A-GE-TX performance question
>
> There was a good thread on Cisco-nsp regarding this exact 
> subject recently.
> My recollection is that both X6148 and X6148A have just 6 1GB ASICs.
> Therefore the over subscription rate is 8:1. The biggest 
> difference between these LC's is that X6148A will support 
> large MTU whereas X6148 will not.
>
> -b
>
>
> On Thu, Sep 10, 2009 at 2:17 PM, Scott Spencer 
> <scott () dwc-computer com>wrote:
>
> >  Are the X6148A cards dedicated 1 gb/s uplink for each port 
> ( shared 
> > 32 Gb/s bus , as long as each port is it's own 1 gb/s still to the 
> > 32gb/s bus and not shared with 7 other ports, so effectively just 
> > 125Mb/s per port then if all used at full/even capacity) ?
> >
> > I can't really find anything much on X6148A internal architecture 
> > online, but it would seem that each port gets its own 1gb/s link to 
> > the card/backplane, and that the bottleneck then is the 32gb/s 
> > backplane (which is fine, as long as it's not 1 gb/s per 
> each set of 8 ports!).
> > Best regards,
> >
> > Scott Spencer
> > Data Center Asset Recovery/Remarketing Manager Duane Whitlow & Co. 
> > Inc.
> > Nationwide Toll Free: 800.977.7473.  Direct: 972.865.1395  Fax:
> > 972.931.3340
> >  <mailto:scott () dwc-computer com> scott () dwc-computer com 
> > <http://www.dwc-it.com/> www.dwc-it.com Sales of new and used 
> > Cisco/Juniper/F5/Foundry/Brocade/Sun/IBM/Dell/Liebert
> > and more ~
>
>
> --
> Bill Blackford
> Network Engineer