Planning the System
Setting WAN Bandwidth Limits Between Network Regions
68
Administrator’s Guide for Avaya Communication Manager
November 2003
Each phone in a Call Coverage path now rings twice before the call routes to the next coverage
point. The
Local Cvg Subsequent Redirection/CFWD No Ans Interval
field also controls the
number of rings before the call is forwarded when you use Call Forwarding for busy/don’t answer
calls. This applies only to calls covered or forwarded to local extensions. Use Off-Net to set the
number of rings for calls forwarded to public network extensions.
Setting WAN Bandwidth Limits Between Network
Regions
Using the Communication Manager Call Admission Control: Bandwidth Limitation (CAC-BL) feature,
you can specify a VOIP bandwidth limit between any pair of IP network regions, and then deny calls that
need to be carried over the WAN link that exceed that bandwidth limit. Bandwidth limits may be
administered in terms of:
•
Kbit/sec WAN facilities
•
Mbit/sec WAN facilities
•
Explicit number of connections
•
No limit
It is highly recommended that you have the following design information before setting the bandwidth
limits and mapping the connections:
1
Network topology and WAN link infrastructure.
2
An understanding of the Committed Information Rate (CIR) for the WAN infrastructure.
3
Overlay/design of the Network Regions mapped to the existing topology.
4
Codec sets administered in the system.
5
Bandwidth is assumed to be full duplex.
The following table can be used to help assess how much bandwidth (in Kbits /sec) is used for various
types of codeecs and packet sizes. The values shown assume a 7 byte L2 WAN header (and are rounded
up).
These values, when compared to the actual bandwidth used for 8 byte as well as 10 byte L2 WAN headers
are not significantly different. In some cases, the rounded up values shown above are greater than values
used for 10 bytes.
Table 3: Bandwidth usage (in Kbits/sec) based on packet size and codec selection
Packet Size
10 ms
20 ms
30 ms
40 ms
50 ms
60 ms
G.711
102
83
77
74
72
71
G.729
46
27
21
18
16
15
G.723-6.3
NA
NA
19
NA
NA
13
G.723-5.3
NA
NA
18
NA
NA
12