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,
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