[e2e] queuing/dropping algorithms *actually* deployed

Chris Kappler chrisk at mysticlabs.com
Thu Jun 22 07:08:19 PDT 2006


One way to go about analyzing this is to look at the product placement
graphs of the major manufacturers and cross-reference that with the
supported configurations.  



http://www.cisco.com/en/US/products/hw/routers/index.html  (click on Routers
for Service Providers)



I have first-hand knowledge of some of the mid- to hi-end Cisco platforms
which enable WRED and some degree of fairness automatically on every
classification type that is created.  The user is then capable of
configuring large scale traffic classification and associated QoS.  Many of
the large routers have so many interfaces that some degrees of QoS is needed
internally just to keep the links full.


Just about every platform, including my linksys router at home, supports
simple priorities.  I have this feature enabled to prevent my wife's photo
uploads from knocking my VoIP phone off-line.  The higher-end Cisco routers
support what is called the modular QoS CLI which is basically a set of
classification commands and the corresponding QoS treatment for each class.
The first link below makes me think that Juniper has a similar command set.


Configuration pointers:




Most service providers take provisioning and QoS pretty seriously since
bandwidth and differentiated services are at the heart of their revenue
stream.  Big telephone companies seem to have well educated QoS staff that
asks hard questions of routing manufactures.  I don't have first-hand
knowledge on other zones of the net such as core or customer premises.
However, I have heard more than once that companies deploying VoIP services
internally usually require a re-vamp of their internal QoS before their
fancy new telephones start working as well as the old ones did :)


I hope this helps,

Chris Kappler



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