ZyXEL Communications P-661HW Series User Manual

P-661H/HW Series User’s Guide

Chapter 15 Bandwidth Management

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• Research requires more bandwidth but only gets its budgeted 2048 kbps because all of the 

unbudgeted and unused bandwidth goes to the higher priority sales and marketing 
classes. 

The following table shows the amount of bandwidth that each class gets.

Suppose that all of the classes except for the administration class need more bandwidth.

• Each class gets up to its budgeted bandwidth. The administration class only uses 1024 

kbps of its budgeted 2048 kbps. 

• The ZyXEL Device divides the total 3072 kbps total of unbudgeted and unused 

bandwidth equally among the other classes. 1024 kbps extra goes to each so the other 
classes each get a total of 3072 kbps. 

You can set the bandwidth management speed for an interface higher than the interface’s 
actual transmission speed. Higher priority traffic gets to use up to its allocated bandwidth, 
even if it takes up all of the interface’s available bandwidth. This could stop lower priority 
traffic from being sent. The following is an example.

If you use VoIP and NetMeeting at the same time, the device allocates up to 500 Kbps of 
bandwidth to each of them before it allocates any bandwidth to FTP. As a result, FTP can only 
use bandwidth when VoIP and NetMeeting do not use all of their allocated bandwidth.

Suppose you try to browse the web too. In this case, VoIP, NetMeeting and FTP all have 
higher priority, so they get to use the bandwidth first. You can only browse the web when 
VoIP, NetMeeting, and FTP do not use all 1000 Kbps of available bandwidth.

Table 96   Fairness-based Allotment of Unused and Unbudgeted Bandwidth Example

Root Class: 10240 kbps

Administration: 1024 kbps

Sales: 3072 kbps

Marketing: 3072 kbps

Research: 3072 kbps

Table 97   Over Allotment of Bandwidth Example

Actual outgoing bandwidth available on the interface: 1000 kbps

Root Class: 1500 kbps  (same 

as Speed setting)

VoIP traffic (Service = SIP): 500 Kbps

High

NetMeeting traffic (Service = H.323): 500 kbps

High

FTP (Service = FTP): 500 Kbps

Medium