Queuing Network Traffic on Cisco Routers Using Custom Queuing

Unlike priority queuing (which will always empty higher-priority queues first), custom queuing allows you to assign bandwidth to different types of traffic based on criteria like protocol and port number. Custom queuing works in a round-robin fashion, moving from queue to queue, ensuring that each is allocated their apportioned bandwidth.

Custom queuing defines a transmission size for each queue in bytes. For example, FTP traffic may be assigned a byte size of 3000, while telnet and HTTP traffic are each defined a byte size of 1500. This would effectively split the bandwidth up such that FTP would have approximately 50% of the bandwidth, while telnet and HTTP would each have approximately 25%. In cycling through the queues, custom queuing would access the FTP queue, send 3000 bytes of data (which would be rounded up to complete a packet if necessary), and then move on to the telnet queue, where it would send 1500 bytes, and so on. Up to 16 custom queues can be defined for a given interface

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of 2000Trainers.com. He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.