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