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3 bandwidth management priorities, 7 over allotment of bandwidth, 8 configuring summary – ZyXEL Communications P-660H-Tx v2 User Manual

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Chapter 12 Bandwidth Management

P-660H-Tx v2 User’s Guide

159

12.6.3 Bandwidth Management Priorities

The following table describes the priorities that you can apply to traffic that the ZyXEL
Device forwards out through an interface.

12.7 Over Allotment of Bandwidth

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.

12.8 Configuring Summary

Click Advanced > Bandwidth MGMT to open the screen as shown next.
Enable bandwidth management on an interface and set the maximum allowed bandwidth for
that interface.

Table 55 Bandwidth Management Priorities

PRIORITY LEVELS: TRAFFIC WITH A HIGHER PRIORITY GETS THROUGH FASTER WHILE

TRAFFIC WITH A LOWER PRIORITY IS DROPPED IF THE NETWORK IS CONGESTED.

High

Typically used for voice traffic or video that is especially sensitive to jitter (jitter

is the variations in delay).

Mid

Typically used for “excellent effort” or better than best effort and would include

important business traffic that can tolerate some delay.

Low

This is typically used for non-critical “background” traffic such as bulk

transfers that are allowed but that should not affect other applications and

users.

Table 56 Over Allotment of Bandwidth Example

BANDWIDTH CLASSES, ALLOTMENTS

PRIORITIES

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