ZyXEL Communications P-660HW-DX, User Manual

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Chapter 13 Bandwidth Management
P-660HW-Dx User’s Guide
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13.6.3 Bandwidth Management Priorities
The following table describes the priorities that you can apply to traffic that the ZyXEL
Device forwards out through an interface.
13.7 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.
13.8 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 73 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 74 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