Alternatives to storm-control on Cat 6509.

Nick Hilliard nick at foobar.org
Mon Aug 24 15:59:59 CDT 2009


On 24/08/2009 19:03, Holmes,David A wrote:
> Additionally, and perhaps most significantly for deterministic network
> design, the copper cards share input hardware buffers for every 8 ports.
> Running one port of the 8 at wire speed will cause input drops on the
> other 7 ports. Also, the cards connect to the older 32 Gbps shared bus.

IMO, a more serious problem with the 6148tx and 6548tx cards is the 
internal architecture, which is effectively six internal managed gigabit 
ethernet hubs (i.e. shared bus) with a 1M buffer per hub, and each hub 
connected with a single 1G uplink to a 32 gig backplane.  Ref:

> http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801751d7.shtml#ASIC

In Cisco's own words: "These line cards are oversubscription cards that are 
designed to extend gigabit to the desktop and might not be ideal for server 
farm connectivity".   In other words, these cards are fine in their place, 
but they are not designed or suitable for data centre usage.

I don't want to sound like I'm damning this card beyond redemption - it has 
a useful place in this world - but at the expense of reliability, 
manageability and configuration control, you will get useful features 
(including broadcast/unicast flood control) and in many situations very 
significantly better performance from a recent SRW 48-port linksys gig 
switch than from one of these cards.

Nick




More information about the NANOG mailing list