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Cisco IP Telephony Solution Reference Network Design
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Chapter 4 Media Resources
Conferencing and Transcoding
Conferencing and Transcoding
This section describes how to calculate the number of DSP resources needed to support the conferencing
and transcoding requirements for your IP telephony system.
NM-HDV and NM-HDV-FARM
The NM-HDV and NM-HDV-FARM provide DSP resources that can be used for voice termination,
conferencing, or transcoding. The following hardware platforms can support the NM-HDV and
NM-HDV-FARM modules:
·
Cisco VG200
·
Cisco 2600 Series
·
Cisco 3620, 3640, 3645, and 3660
·
Cisco 3725 and 3745
You can mix NM-HDV and NM-HDV-FARM modules in the same chassis, but not all chassis can be
completely populated by these modules.
shows the number of modules that each type of
hardware platform can support.
GSM Full Rate (GSMFR)
30
Fax Relay
30
G.729, G.729b, G.729a, G.729ab
30
G.728
40
G.723.1 (5.3K, 6.3K); G.723.1a (5.3K, 6.3K)
40
GSM Enhanced Full Rate (GSMEFR)
40
Modem Relay
1
40
1.
Modem relay is not currently supported in Cisco IOS Release 12.2.15ZJ.
Table 4-4
Flex Mode Channel Calculations for the NM-HD-xx (TI 5510) Platforms (continued)
Codec Type
MIPS Credits Required
Table 4-5
Maximum Number of Modules per Gateway
Cisco IOS Gateway Type
Maximum NM-HDV or NM-HDV-FARM Modules per Gateway
Cisco VG200
1
, 2600
2
, or 3620
1.
The VG200 is no longer available for purchase and has been replaced by the Cisco 2610 Router. Existing models of the
VG200 can still be used in an IP Telephony deployment.
2.
For IP Telephony applications, use Cisco 2600XM routers. For memory considerations for the Cisco 2600 routers, see the
Product Bulletin at
1
Cisco 3640
3
Cisco 3660
6
Cisco 3725
3
3.
For IP Telephony applications, the Cisco 3700 Series routers provide better performance than the Cisco 3600 Series.
2
Cisco 3745
4