[c-nsp] 6500 QoS

[Randy McAnally]

We got minor packet loss and noticeably slower speeds off the bat with 'mls
qos' enabled with all defaults, even with only 40-50% interface utilization. 
In fact it took a while to figure it out.  Be very careful when you enable it
if even minor packet loss will be an issue.

--
Randy
www.FastServ.com

---------- Original Message -----------
From: ML <ml at kenweb.org>
To: cisco-nsp at puck.nether.net
Sent: Wed, 19 Aug 2009 23:19:24 -0400
Subject: [c-nsp] 6500 QoS

> I'm about to turn on "mls qos" for the first time on a 6509E.
> 
> I would like some background information from the QoS experts on 
> this list.
> 
> Last time I turned on "mls qos" it was a 3560 which has certain 
> undesirable defaults when "mls qos" is turned on.  I want avoid the 
> same result with the 6509 which is our Internet edge device.  What I 
> want to accomplish is to mark all incoming traffic from our transit 
> link to CS0.
> 
> I don't want to inadvertently get clobbered by a default limit of x% 
> for egress queue bandwidth that I'm not expecting.
> 
> If I understand what I've found out so far:
> 
> On the WS-X6724-SFP:
> 
> Seems all possible CoS values are mapped to queue 1 for ingress and 
> egress.  The WRR queue ratios are 100,0,0 for queues 1,2,3 (4 is 
> priority?) So Queue can utilize 100% of the interface bandwidth.  So 
> by default I shouldn't seem traffic getting bottlenecked where it 
> wasn't before because of some default config?
> 
> Is the simplest configuration to turn on mls qos globally and use a 
> service policy to set all input to dscp cs0?
> 
> Thanks
> 
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------- End of Original Message -------