pontification bloat (was 10GE TOR port buffers (was Re: 10G switch recommendaton))

Leo Bicknell bicknell at ufp.org
Fri Jan 27 20:08:10 CST 2012


In a message written on Sat, Jan 28, 2012 at 10:31:20AM +0900, Randy Bush wrote:
> (embarrassed to say, but to set an honest example, i do not believe iij
> does)

I also want to take this opportunity to say there are some cool new
features (that I have not had a chance to deploy myself) that may have
been missed if queueing wasn't your day job for the last few years.

"QoS: Time-Based Thresholds for WRED and Queue Limit for the Cisco 12000
 Series Router"

http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/12stbwr.html

Don't want to do math on how big the queue should be?  Configure by
ms:

outer> enable
Router# configure terminal
Router (config)# policy-map policy1
Router(config-pmap)# class class-default
Router(config-pmap-c)# bandwidth percent 80
Router(config-pmap-c)# random-detect
Router(config-pmap-c)# random-detect precedence 2 4 ms 8 ms 
Router(config-pmap-c)# exit 
Router(config-pmap)# exit 
Router(config)# interface serial8/0/0:0.1000
Router(config-subif)# service-policy output policy1
Router(config-subif)# end

That's a 4ms to 8ms buffer!  Handy, nice!

Another frame concept brought to IP is ECN, congestion notification.

http://www.cisco.com/en/US/docs/ios-xml/ios/qos_conavd/configuration/15-0m/qos-conavd-wred-ecn.html

Router(config)# policy-map pol1
 Router(config-pmap)# class class-default
 Router(config-pmap-c)# bandwidth per 70
 Router(config-pmap-c)# random-detect
 Router(config-pmap-c)# random-detect ecn

Requires other bits in the network to be ECN aware, but if they are,
good stuff.

-- 
       Leo Bicknell - bicknell at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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