Re: Priority Queue command behaviour

Hi Gary,

There aren't many options after the protocol keyword that I could test
this with.Either they are Layer-2 protocols such as CDP or ARP or
protocols which I don't know much about..This is what I have :
R1(config)#priority-list 1 protocol ?
  arp IP ARP
  bridge Bridging
  bstun Block Serial Tunnel
  cdp Cisco Discovery Protocol
  clns ISO CLNS
  clns_es ISO CLNS End System
  clns_is ISO CLNS Intermediate System
  cmns ISO CMNS
  compressedtcp Compressed TCP (VJ)
  dlsw Data Link Switching (Direct encapsulation only)
  http HTTP
  ip IP
  ipv6 IPV6
  llc2 llc2
  pad PAD links
  pppoe PPP over Ethernet
  qllc qllc protocol
  rsrb Remote Source-Route Bridging
  snapshot Snapshot routing support
  stun Serial Tunnel

I could obviously do a "protocol ip" and then select the tcp or udp
port numbers , but that always works. What does not work is the
"protocol http" command and I have tried not just a telnet on port 80
but a http transfer between the devices as well and it still does not
recognise the packets as HTTP, so I wonder what is it that the router
is looking for here.

Thanks,
Ravi

On Tue, Jun 16, 2009 at 10:16 PM, Gary
Duncanson<gary.duncanson_at_googlemail.com> wrote:
> Hi Ravi,
>
> I will take a stab at this.
>
> Perhaps your PQ
>
> R1(config)#priority-list 1 protocol http medium
>>
>> R1(config)#priority-list 1 default low
>
> is simply not recognising your telnet attempt, albeit on port 80 as http
> protocol? So it goes into the low queue.
>
> Try changing http to another protocol and do telnets on its port number and
> see.
>
> Similarly change the line in the PQ that does work to use the new tcp port
> number and compare the results.
>
> Regards
> Gary
> ----- Original Message ----- From: "Ravi Singh" <way2ccie_at_googlemail.com>
> To: "Cisco certification" <ccielab_at_groupstudy.com>
> Sent: Tuesday, June 16, 2009 12:12 PM
> Subject: 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 Wed Jun 17 2009 - 00:23:24 ART