[j-nsp] QOS Mechanics - PLP and drop-profiles behaviour

[Josef Buchsteiner]

Wednesday, February 11, 2004, 12:45:28 PM, you wrote:

DP> Under test, I set my scheduler drop-profiles to be acting only against tcp
DP> traffic.  Now, if I wind a queue up so that it is heavily congested but only
DP> with UDP streams, I still see the sub-queue classified as 'high'
DP> drop-priority more aggressively dealt with than the 'low' drop-priority
DP> classified sub-queue  (I use the term sub-queue here for the diferentiation
DP> between high and low drop priroties.)

DP> In fact, even if I remove all drop-profiles so that allegedly everything
DP> uses the default-drop-profile <fill-level 100 drop 100> I see the same as
DP> above on TCP and non-tcp traffic.  Do I assume from this that the PLP status
DP> that is used internally to differentiate the high and low traffic within a
DP> queue (show class-of-service forwarding-table ) IS used during heavy
DP> congestion to differentiate between the classifications..?

    it is not used.

DP>   That is, the
DP> high/low dichotomy isn't just for differnent WRED drop-profiles to be set?

    I  don't  know  exactly what you did but if all is default setting
    there is no differentiation or different treatment between plp set
    or not set for WRED unless you define a different behavior. If you
    still  see  a difference then you need to look at your test bed to
    get an explanation.

    Josef


DP> In fact, I'm sure this is happening and although it is in fact useful to
DP> prioritise the 'low' sub-queue during heavy congestion for all traffic,  I'd
DP> like to know how it works so I can possibly set a non-tcp drop-profile set
DP> to compliment the internal handling based on PLP...

DP> Damon Pegg
DP> Network Development
DP> Easynet plc
DP> t:    0207 900 7075
DP> f:    0207 900 4443
DP> m:    07931 406206
DP> e:    damon.pegg at uk.easynet.net
DP> w:    www.easynet.com  

DP> _______________________________________________
DP> juniper-nsp mailing list juniper-nsp at puck.nether.net
DP> http://puck.nether.net/mailman/listinfo/juniper-nsp