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Custom Queueing (CQ) On Cisco Routers

A Cisco Certification Exam Review

By Chris Bryant, CCIE #12933

The syntax of CQ can be a little confusing at first. By following this five-step process and using IOS Help, you'll be configuring your own custom queues in no time!

First, define the byte-count and packet limit of each queue as desired.

R1(config)#queue-list 1 queue 2 ?
byte-count Specify size in bytes of a particular queue
limit Set queue entry limit of a particular queue

R1(config)#queue-list 1 queue 2 limit ?
<0-32767> number of queue entries

R1(config)#queue-list 1 queue 2 limit 200

Define the traffic that will use these queues with access lists and the queue-list command. Quite a few options are shown below.

R1(config)#access-list 123 permit ip 100.1.1.0 0.0.0.127 200.2.2.0 0.0.0.15

Using the queue-list command with the protocol option:

R1(config)#queue-list 1 protocol ip ?
<0-16> queue number

R1(config)#queue-list 1 protocol ip 2 ?
fragments Prioritize fragmented IP packets
gt Classify packets greater than a specified size
list To specify an access list
lt Classify packets less than a specified size
tcp Prioritize TCP packets 'to' or 'from' the specified port
udp Prioritize UDP packets 'to' or 'from' the specified port
<cr>

R1(config)#queue-list 1 protocol ip 2 list 123

Using the queue-list command with the interface option:

R1(config)#queue-list 1 interface ?
BRI ISDN Basic Rate Interface
Null Null interface
Serial Serial
TokenRing IEEE 802.5

R1(config)#queue-list 1 interface serial1 ?
<0-16> queue number

R1(config)#queue-list 1 interface serial1 3

R1(config)#queue-list 1 ?
default Set custom queue for unspecified datagrams
interface Establish priorities for packets from a named interface
lowest-custom Set lowest number of queue to be treated as custom
protocol priority queueing by protocol
queue Configure parameters for a particular queue
stun Establish priorities for stun packets

R1(config)#queue-list 1 queue 3 ?
byte-count Specify size in bytes of a particular queue
limit Set queue entry limit of a particular queue

R1(config)#queue-list 1 queue 3 byte-count ?
<1-16777215> size in bytes

R1(config)#queue-list 1 queue 3 byte-count 5000

R1(config)#queue-list 1 default ?
<0-16> queue number

R1(config)#queue-list 1 default 5
R1(config)#queue-list 1 protocol ip ?
<0-16> queue number

R1(config)#queue-list 1 protocol ip 4 ?
fragments Prioritize fragmented IP packets
gt Classify packets greater than a specified size
list To specify an access list
lt Classify packets less than a specified size
tcp Prioritize TCP packets 'to' or 'from' the specified port
udp Prioritize UDP packets 'to' or 'from' the specified port
<cr>

R1(config)#queue-list 1 protocol ip 4 tcp www

R1(config)#queue-list 1 default ?
<0-16> queue number

R1(config)#queue-list 1 default 5

Use the custom-queue-list command to apply the queue-list to the desired interface.

R1(config)#int serial0
R1(config-if)#custom-queue-list 1

Finally, verify with show queueing custom and show queueing interface.

R1#show queueing custom
Current custom queue configuration:

List Queue Args
1 5 default
1 2 protocol ip list 123
1 3 interface Serial1
1 4 protocol ip tcp port www
1 2 limit 200
1 3 byte-count 5000

R1#show queueing interface serial0
Interface Serial0 queueing strategy: custom

Output queue utilization (queue/count)
0/0 1/0 2/0 3/0 4/0 5/0 6/0 7/0 8/0
9/0 10/0 11/0 12/0 13/0 14/0 15/0 16/0

To your success,

Chris Bryant