Extreme Networks EPICenter 6.0, Reference Manual

Page: 560 / 580

Voice over IP Manager
EPICenter Reference Guide
560
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The first two columns of Table 66 show various combinations of the compression algorithms and
number of IP phone ports.
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The third column shows the total bandwidth requirement calculated based on the compression rate
and number of ports as shown in the first two columns.
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The fourth column (Min bandwidth needed for egress ports) shows the corresponding minimum
bandwidth that should be configured for a gigabit egress port such as the egress port on the
upstream switch.
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The last column shows the actual maximum number of simultaneous calls that can be supported by
the minimum bandwidth.
Find the minimum bandwidth setting in the table that corresponds to your VoIP setup (number of
phones and compressions algorithm. Then, make sure the minimum bandwidth setting for the VLAN
on your upstream switch(es) meets this requirement. You can change the bandwidth settings for an
individual switch using the Configure VoIP QoS Parameters dialog. See
“Configuring QoS Settings” on
page 560 for more information.
Note that the bandwidth calculation algorithm always assumes there is a one-to-one correspondence
between the number of IP phones and the number of ingress ports included in the VoIP VLAN.
Another situation that may result in an incorrect bandwidth calculation is where multiple IP phone are
connected via a hub to a single ingress port on a switch. In this configuration the VoIP Manager will
underestimate the number of IP phone connections, and will therefore underestimate the required
minimum bandwidth. In this case, you can also use the information in
Table 66 to help you determine
the correct minimum bandwidth in the QoS profile for the VoIP VLAN on the switch.
Configuring QoS Settings
Changing the default configuration attributes does not actually configure any settings on the switches.
The information is provided to simplify the configuration task for the user and to recommend
Table 66: Minimum Bandwidth Requirements and Calculations for VoIP VLAN
Compression
algorithm Number of
phones
(one per port) Total calculated
bandwidth Min bandwidth
needed for egress ports Max number
of phones
supported
G.711, rate=64 Kbps 0~100 0~7 Mbps 10 Mbps (Min=1%) 156
G.711, rate=64Kbps 100~200 7~13 Mbps 20 Mbps(Min=2%) 312
G.711, rate=64Kbps 200~300 13~20 Mbps 20 Mbps(Min=2%) 312
G.711, rate=64Kbps 300~400 20~26 Mbps 30 Mbps(Min=3%) 468
G.729, rate=8.0Kbps 0~100 0~1 Mbps 10 Mbps(Min=1%) 1250
G.729, rate=8.0Kbps 100~200 1~2 Mbps 10 Mbps(Min=1%) 1250
G.729, rate=8.0Kbps 200~300 2~3 Mbps 10 Mbps(Min=1%) 1250
G.729, rate=8.0Kbps 300~400 3~4 Mbps 10 Mbps(Min=1%) 1250
G.723.1, rate=6.4Kbps 0~100 0~1 Mbps 10 Mbps(Min=1%) 1562
G.723.1, rate=6.4Kbps 100~200 1~2 Mbps 10 Mbps(Min=1%) 1562
G.723.1, rate=6.4Kbps 200~300 2 Mbps 10 Mbps(Min=1%) 1562
G.723.1, rate=6.4Kbps 300~400 2~3 Mbps 10 Mbps(Min=1%) 1562