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Re: EF and BE traffic--unexplained behaviour




Can I ask what type of traffic is it? 

tcp/udp

What is the value of the tos byte that you mark the EF traffic with?

0xb8/0x2e

Did you monitor the tcpdump o/p to see if the packets are correctly 
marked? Use ttt or tcptrace or any other tcpdump analysing package to plot
the graphs for you.

I am mystified by your throughput results, you should atleast get 3 to
3.5Mpbs for both EF and BE. Can you give me an idea of your network, is it
just 2 machines connected back to back?

Cheers
Muneyb

On Thu, 3 Aug 2000, Aditya Chugh wrote:

> Hello Everybody,
> 
> I am using my modified version of TTCP (with which I can set the TOS
> byte of my packets ) to test the throuput and the time taken to traverse
> 
> the path from A to B.
> A and B are both linux machines  connected to the same local LAN. The
> kernel of A
> is diffserv enabled,while B has plain vanilla Linux.
> I run a modified version of "EFCBQ" - the standard script to set the
> diffserv queues for EF and BE.
> I assign both EF and BE  4 Mbit of rate ( out of total b/w of 10Mbit ) I
> 
> make both the queues "bounded and isolated" ...so they can neither
> borrow nor lend b/w. The weight assigned to each is 1.  (Script attached
> 
> below)
> 
> When I send both EF and BE packets simultaneously from A to B , I get EF
> 
> b/w about 467 Kb/sec
> and BE bandwidth about 340Kb/sec---which is OK according to me.
> When I send only EF packets from A to B the b/w is reduced to around 260
> 
> Kb/sec
> When I send only BE packets the b/w I get is around 336 Kb/sec ?
> These results are getting repeated consistently. (measurements have been
> 
> taken 8-10 times for each case)
> Isn't this strange ??  How do we explain it ?
> I am totally stumped ....and  am unable to come up with a coherent
> explanation
> 
> Any help/advice/explanation from you will be sincerely appreciated.
> Thanks in advance.Please reply soon.
> regards,
> Aditya
> 
> 
> 
> 
> 
> The script I used:---
> 
> #!/usr/bin/perl
> #
> $TC = "/usr/local/iproute2/tc/tc" ;
> $DEV = "dev eth0";
> print "$TC qdisc add $DEV handle 1:0 root dsmark indices 64
> set_tc_index\n";
> print "$TC filter add $DEV parent 1:0 protocol ip prio 1 tcindex ".
>   "mask 0xfc shift 2\n";
> print "$TC qdisc add $DEV parent 1:0 handle 2:0 cbq bandwidth ".
>  "10Mbit cell 8 avpkt 1000 mpu 64\n";
> #
> # EF class
> #
> print "$TC class add $DEV parent 2:0 classid 2:1 cbq bandwidth ".
>  "10Mbit rate 4Mbit avpkt 1000 prio 1 bounded isolated ".
>  "allot 1514 weight 1 maxburst 4 \n";
> # packet fifo for EF?
> print "$TC qdisc add $DEV parent 2:1 pfifo limit 4\n";
> print "$TC filter add $DEV parent 2:0 protocol ip prio 1 ".
>    "handle 0x2e tcindex classid 2:1 pass_on\n";
> #
> # BE class
> #
> print "#BE class(2:2) \n";
> print "$TC class add $DEV parent 2:0 classid 2:2 cbq bandwidth ".
>  "10Mbit rate 4Mbit avpkt 1000 prio 7 bounded isolated allot 1514 weight
> 
> 1 ".
>  "maxburst 4  split 2:0 defmap 0xffff \n";
> print "$TC qdisc add $DEV parent 2:2 red limit 4KB ".
>    "min 20kBit max 4KB burst 4 avpkt 1000 bandwidth 10Mbit ".
>    "probability 0.02\n";
> print "$TC filter add $DEV parent 2:0 protocol ip prio 2 ".
>    "handle 0 tcindex mask 0 classid 2:2 pass_on\n";
> 
> 
> 
> 

_________________________________________________________
Muneyb Minhazuddin - Telecommunications Research Engineer    
CSIRO Telecommunication and Industrial Physics                
Marsfield, NSW, Australia.                                    
                                                             
Phone no. : 61 2 9372 4113
FAX       : 61 2 9372 4490          
e-mail    : mminhazu@tip.csiro.au  
Home Page : http://www-networks.tip.csiro.au/~mminhazu
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