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RE: Question about setting DSCP value (IEWB Lab 20, question 8.3) posted 11/06/2006
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Thanks for the help :)

-----Original Message-----
From: Victor Cappuccio [mailto:vcappuccio@xxxxxxxxx] 
Sent: Monday, November 06, 2006 9:26 AM
To: Michael Zuo; ccielab@xxxxxxxxxxxxxx
Subject: RE: Question about setting DSCP value (IEWB Lab 20, question
8.3)

Hi Michael,

Maybe because a shake of task 8.2 + 8.3 :)

If you look at this output

R1#show queueing interface s1/1
Interface Serial1/1 queueing strategy: random early detection (WRED)
    Exp-weight-constant: 9 (1/512)
    Mean queue depth: 0

   dscp          Random drop      Tail drop    Minimum Maximum  Mark
                  pkts/bytes       pkts/bytes    thresh  thresh  prob
   af11      0/0              0/0           33      40  1/10
   af12      0/0              0/0           28      40  1/10
   af13      0/0              0/0           24      40  1/10
   af21      0/0              0/0           33      40  1/10
   af22      0/0              0/0           28      40  1/10
   af23      0/0              0/0           24      40  1/10
   af31      0/0              0/0           33      40  1/10
   af32      0/0              0/0           28      40  1/10
   af33      0/0              0/0           24      40  1/10
   af41      0/0              0/0           33      40  1/10
   af42      0/0              0/0           28      40  1/10
   af43      0/0              0/0           24      40  1/10
    cs1      0/0              0/0           22      40  1/10
    cs2      0/0              0/0           24      40  1/10
    cs3      0/0              0/0           26      40  1/10
    cs4      0/0              0/0           28      40  1/10
    cs5      0/0              0/0           31      40  1/10
    cs6      0/0              0/0           33      40  1/10
    cs7      0/0              0/0           35      40  1/10
     ef      0/0              0/0           37      40  1/10
   rsvp      0/0              0/0           37      40  1/10
default       0/0              0/0           20     40  1/10
R1#

You can see that CS5, CS6 and CS7 has the maximum Average Queue Min and
Max Values to start dropping packets, so setting the DSCP to CS5 or CS6
or CS7 or EF would be correct, since the default traffic is DSCP 0 20/40
to start dropping. (why they took CS5, just because it look correct
setting the value to 5 in IPP, the 6 and 7 are for Routing and Keepalive
messages (But since this is not a best practice test I would assume that
it could be also correct setting the flow for that server to 6 o 7)

Now why not 63, well I think this is because, there is no predefined Min
and Max Drop Values for the average Q, so you would have to manually
configure those values per that number (PHB)

interface Serial1/1
 no ip address
 encapsulation frame-relay
 random-detect dscp-based
 random-detect dscp 63 26 49 1
 serial restart-delay 0
 clockrate 9600
end

R1#show queueing interface s1/1 | be 63
     63      0/0              0/0           26      49  1/1
   rsvp      0/0              0/0           37      40  1/10
default       0/0              0/0           20     40  1/10

My 0.00000002 Nanobits
Victor.-

-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
Michael Zuo
Sent: Domingo, 05 de Noviembre de 2006 07:25 p.m.
To: ccielab@xxxxxxxxxxxxxx
Subject: Question about setting DSCP value (IEWB Lab 20, question 8.3)

Hi Group,



This question is asking us to set DSCP value on certain HTTP traffic so
that "random-detect dscp-based" WRED will be least likely to drop HTTP
traffic





Does anyone know the reason why the solution guide is setting the DSCP
to cs5 instead of value 63 ?



Thanks a lot

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