Custom Queuing Classification

Custom Queuing Classification

• queue-list list-number protocol protocol-name queue-number queue-keyword keyword-value

• Router(config)#

• Classifies the packet into a custom queue based on protocol and other protocol-specific criteria
• Selection criteria identical to priority queuing

• queue-list list-number interface incoming-intf queue-number

• Router(config)#

• Classifies the packet into a custom queue based on incoming interface

Custom Queuing Classification (cont.)

• queue-list list-number default queue-number

• Router(config)#

• Classifies all unclassified packets into a default queue

• custom-queue list-number

• Router(config-if)#

• Starts custom queuing on an interface and assigns a specified CQ definition to the interface

Custom Queuing Scheduling Parameters

• queue-list list queue queue-number byte-count bc

• Router(config)#

• Specifies the lower boundary on how many bytes the system allows to be delivered from a given queue during one round-robin cycle
• Default: 1500 bytes

• queue-list list queue queue-number limit limit

• Router(config)#

• Specifies the maximum number of packets in a queue
• Incoming packets are tail-dropped if the limit is exceeded
• Default: 20

Custom Queuing with Pre-emptive Queues

• Custom Queuing System

• Hardware
• Queuing System

• Class 1?

• Queue 1

• Round-
• Robin
• Scheduler

• Inter-face

• Forwarded Packets

• Hardware Q

• Tail Drop

• Class 2?

• Queue 2

• Tail Drop

• Class 16?

• Queue 16

• Tail Drop

• Class 0?

• Queue 0

• Tail Drop

• Pre-emptive
• Scheduler

• Custom queuing has Queue 0 for system and link-level messages that use pre-emptive scheduling.

• Queue 1 is the lowest custom queue that is serviced by the round-robin scheduler.

Custom Queuing with Pre-emptive Queues (cont.)

• Custom Queuing System

• Hardware
• Queuing System

• Class 1?

• Queue 1

• Round-
• Robin
• Scheduler

• Inter-face

• Forwarded Packets

• Hardware Q

• Tail Drop

• Class 2?

• Queue 2

• Tail Drop

• Class 16?

• Queue 16

• Tail Drop

• Custom queues can be configured to use the pre-emptive scheduler.

• Queue 2 is now the lowest custom queue that is serviced by the round-robin scheduler.

• Class 0?

• Queue 0

• Tail Drop

• Pre-emptive
• Scheduler

Custom Queuing Scheduling Parameters

• Set the lowest queue to be treated as the custom queue.
• Queues below the specified queue are pre-emptive priority queues (Q1 having the highest priority).
• Queue 0 is always treated as pre-emptive.
• System and link-level messages are classified in Q0 by default.

• queue-list list-number lowest-custom queue-number

• Router(config)#

Custom Queuing Example

• Core

• WAN Core

• Branch

• Office

• E0

• E1

• interface serial 1/0
• custom-queue-list 5
• !
• queue-list 5 protocol ip 1 list 101
• queue-list 5 queue 1 limit 40
• queue-list 5 lowest-custom 2
• queue-list 5 interface ethernet 0/0 2
• queue-list 5 queue 2 byte-count 3000
• queue-list 5 protocol ip 3
• queue-list 5 queue 3 byte-count 5000
• queue-list 5 default 4
• !
• access-list 101 permit ip any any precedence 5

Custom Queuing–show interface

• Router#show interface serial 1/0
• Serial1/0 is up, line protocol is up
• Hardware is M4T
• Internet address is 20.0.0.1/8
• MTU 1500 bytes, BW 19 Kbit, DLY 20000 usec, rely 255/255, load 107/255
• Encapsulation HDLC, crc 16, loopback not set
• Keepalive set (10 sec)
• Last input 00:00:00, output 00:00:00, output hang never
• Last clearing of "show interface" counters never
• Input queue: 0/75/0 (size/max/drops); Total output drops: 0
• Queueing strategy: custom-list 5
• Output queues: (queue #: size/max/drops)
• 0: 0/20/0 1: 0/40/0 2: 0/20/0 3: 0/20/0 4: 0/20/0
• 5: 0/20/0 6: 0/20/0 7: 0/20/0 8: 0/20/0 9: 0/20/0
• 10: 0/20/0 11: 0/20/0 12: 0/20/0 13: 0/20/0 14: 0/20/0
• 15: 0/20/0 16: 0/20/0
• … rest ignored ...