[ns] ecn in nortel diffserv!!!

Thu, 4 Jan 2001 13:48:09 -0500

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> Hi,
> 
> The priority scheduler in the Nortel Diffserv module is a strict priority
> scheduler.  Any packet in Queue 0 will be transmitted before a packet in
> Queue 1.
> 
> In your scenario, a packet will be queued in Queue 0 if it arrives while
> another packet is being transmitted from either queue.  The scheduler will
> not preempt the transmission of a packet from Queue 1 upon the arrival of
> a packet belonging to Queue 0.
> 
> For WRR, the default weight is set to 1 in the dsREDQueue constructor
> function.
> 
> Regards,
> Jeremy.
> 
> 
> -----Original Message-----
> From:	Kaleelazhicathu R R Kumar [SMTP:kaleelaz@comp.nus.edu.sg]
> Sent:	Thursday, December 28, 2000 8:01 AM
> To:	Baines, Mandeep [CAR:0C24-A:EXCH]
> Cc:	Seddigh, Nabil [CAR:0C24:EXCH]; Peter Pieda; ns-users@isi.edu
> Subject:	Re: [ns] ecn in nortel diffserv!!!
> 
> 
> hi,
> 1)please let me know whether the priority scheduler in nortel diffserv
> implements a static preemptive priority scheduler??
> 
> 2)In the WRR implementation in nortel diffserv,is there any default
> weight for each queue??ie, if i have 2 physical queues with one of the
> queues having 2 logical queues. so if i give a weight of 5 to Queue 0,
> will the queue 1 take any default weight or do i need to specify the
> weight for it too??
>      in my set up , i have 2 physical queues . i have a 32kbps flow going
> thru the queue 0 and a 5Mbps flow thru queue 1. The outgoing bw is 1
> Mbps. i have reserved a bw of 0.2Mbps for the flow thru queue 0. Even
> after that ,i find the packets getting queued at queue 0 when the 5Mbps
> flow goes thru queue 1.
>   i have tried using both the priority scheduler and WRR. The
> static priority preemptive scheduler with a reservation of bw should give
> me a no delay at 0 queue, which is not happening...any clues please??
>   thanks.
>   Renjish.

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<TITLE>RE: [ns] ecn in nortel diffserv!!!</TITLE>
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<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Hi,</FONT>
</P>

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">The priority =
scheduler in the Nortel Diffserv module is a strict priority =
scheduler.&nbsp; Any packet in Queue 0 will be transmitted before a =
packet in Queue 1.</FONT></P>

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">In your scenario, a =
packet will be queued in Queue 0 if it arrives while another packet is =
being transmitted from either queue.&nbsp; The scheduler will not =
preempt the transmission of a packet from Queue 1 upon the arrival of a =
packet belonging to Queue 0.</FONT></P>

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">For WRR, the default =
weight is set to 1 in the dsREDQueue constructor function.</FONT>
</P>

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Regards,</FONT>
<BR><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Jeremy.</FONT>
</P>
<BR>

<P><FONT SIZE=3D1 FACE=3D"Arial">-----Original Message-----</FONT>
<BR><B><FONT SIZE=3D1 FACE=3D"Arial">From:&nbsp;&nbsp;</FONT></B> <FONT =
SIZE=3D1 FACE=3D"Arial">Kaleelazhicathu R R Kumar =
[SMTP:kaleelaz@comp.nus.edu.sg]</FONT>
<BR><B><FONT SIZE=3D1 FACE=3D"Arial">Sent:&nbsp;&nbsp;</FONT></B> <FONT =
SIZE=3D1 FACE=3D"Arial">Thursday, December 28, 2000 8:01 AM</FONT>
<BR><B><FONT SIZE=3D1 =
FACE=3D"Arial">To:&nbsp;&nbsp;&nbsp;&nbsp;</FONT></B> <FONT SIZE=3D1 =
FACE=3D"Arial">Baines, Mandeep [CAR:0C24-A:EXCH]</FONT>
<BR><B><FONT SIZE=3D1 =
FACE=3D"Arial">Cc:&nbsp;&nbsp;&nbsp;&nbsp;</FONT></B> <FONT SIZE=3D1 =
FACE=3D"Arial">Seddigh, Nabil [CAR:0C24:EXCH]; Peter Pieda; =
ns-users@isi.edu</FONT>
<BR><B><FONT SIZE=3D1 =
FACE=3D"Arial">Subject:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT>=
</B> <FONT SIZE=3D1 FACE=3D"Arial">Re: [ns] ecn in nortel =
diffserv!!!</FONT>
</P>
<BR>

<P><FONT SIZE=3D2 FACE=3D"Arial">hi,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">1)please let me know whether the =
priority scheduler in nortel diffserv</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">implements a static preemptive =
priority scheduler??</FONT>
</P>

2)In the WRR implementation in nortel =
diffserv,is there any default
 weight for each queue??ie, if i have =
2 physical queues with one of the
 queues having 2 logical queues. so if =
i give a weight of 5 to Queue 0,
 will the queue 1 take any default =
weight or do i need to specify the
 weight for it too??
 &nbsp;&nbsp;&nbsp;&nbsp; in my set up =
, i have 2 physical queues . i have a 32kbps flow going
 thru the queue 0 and a 5Mbps flow =
thru queue 1. The outgoing bw is 1
 Mbps. i have reserved a bw of 0.2Mbps =
for the flow thru queue 0. Even
 after that ,i find the packets =
getting queued at queue 0 when the 5Mbps
 flow goes thru queue 1.
 &nbsp; i have tried using both the =
priority scheduler and WRR. The
 static priority preemptive scheduler =
with a reservation of bw should give
 me a no delay at 0 queue, which is =
not happening...any clues please??
 &nbsp; thanks.
 &nbsp; Renjish.

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