Priority Queue command behaviour

Hi Group,

I am digging out a pretty old thread on the priority-list usage
command which is here ,( Courtesy - Jason Madsen )

https://www.groupstudy.com/archives/ccielab/200810/msg01834.html

The answer to this question was not definitive at that time and then
it was lost in the GS archives.Also, I could not find any other place
where this behaviour is explained , so here it goes

I have found out that there is a difference between using

priority-list 1 protocol http medium

V/S

priority-list 1 protocol ip medium tcp www

Please look at the test below

..I have the following priority-list created

R1(config)#priority-list 1 protocol ip medium tcp www
R1(config)#priority-list 1 default low
R1(config)#int f0/0
R1(config-if)#priority-group 1

R1#debug priority
Priority output queueing debugging is on

R1#telnet 10.1.12.2 80
Trying 10.1.12.2, 80 ... Open

*Jun 14 21:51:14.501: PQ: FastEthernet0/0: ip (tcp 80) -> medium
*Jun 14 21:51:14.501: PQ: FastEthernet0/0 output (Pk size/Q 60/1)
*Jun 14 21:51:14.505: PQ: FastEthernet0/0: ip (tcp 80) -> medium
*Jun 14 21:51:14.505: PQ: FastEthernet0/0 output (Pk size/Q 60/1)
*Jun 14 21:51:14.509: PQ: FastEthernet0/0: ip (tcp 80) -> medium
*Jun 14 21:51:14.509: PQ: FastEthernet0/0 output (Pk size/Q 60/1)

So this works as expected and the packets are sent to the medium
queue. Now, if I change my priority-list to
R1(config)#priority-list 1 protocol http medium
R1(config)#priority-list 1 default low

and initiate the traffic

R1#debug priority
Priority output queueing debugging is on
R1#
R1#telnet 10.1.12.2 80
Trying 10.1.12.2, 80 ... Open

*Jun 14 21:53:29.125: PQ: FastEthernet0/0: ip (defaulting) -> low
*Jun 14 21:53:29.125: PQ: FastEthernet0/0 output (Pk size/Q 60/3)
*Jun 14 21:53:29.129: PQ: FastEthernet0/0: ip (defaulting) -> low
*Jun 14 21:53:29.129: PQ: FastEthernet0/0 output (Pk size/Q 60/3)
*Jun 14 21:53:29.133: PQ: FastEthernet0/0: ip (defaulting) -> low

The traffic goes into the low queue as a default. So there is a
difference between the two commands. Has anyone encountered this
behaviour before and does someone have a nice explanation to this .. I
am using Version 12.4(7) BTW

Thanks
Ravi

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Received on Tue Jun 16 2009 - 12:12:41 ART