This series of interactive documents uses a typical head office and branch
office in order to demonstrate some common voice network configurations. This
interactive diagram allows you to view network configurations:
This image is interactive!
Click a component to view configuration
and troubleshooting information.
By default, MOH is transmitted using G.711 ulaw codec. In order to generate
G.729 streams for bandwidth efficiency, click Service > Service Parameters
> Cisco IP Voice Media Streaming App in order to enable the G.729 codec
in the Cisco IP voice media streaming application.
Note: To select multiple codecs, press the Ctrl key and click
the desired codec.
Multicast Routing is beyond the scope of this document. However, at a minimum,
you must enable the multicast-routing global command and the ip pim
sparse-dense-mode command on the necessary interfaces that are used in the
For more information on multicast routing, refer to the Cisco
Assign Media Resources to the San Jose and RTP MRG and MRGL
In order to ensure that the San Jose and RTP locations use the correct media
resources, you must configure a media resource group (MRG) to include to appropriate
resources, and then assign that MRG to a resource group list (MRGL) that corresponds
to that location.
For example, create an MRG that includes San Jose resources, and assign that
MRG to an MRGL that belongs to the San Jose location.
This configuration ensures that media resources are used locally, instead of
the WAN that uses scarce bandwidth.
In order to assign media resources to the San Jose and RTP MRG and MRGL, complete
Configure the San Jose and RTP MRGs:
Click Service > Media Resource > Media Resource Group >
Add a New Media Resource Group.
Assign only San Jose media resources to the the MRG-SJ (include the
MOH server), and verify that the Use Multicast check box is checked. Otherwise,
multicast MOH will not work.
Assign only RTP media resources to the the MRG-RTP (include MOH server),
and verify that the Use Multicast check box is checked. Otherwise, multicast
MOH will not work.
Create the MRGLs for San Jose and RTP, and assign the proper MRG:
Click Service > Media Resource > Media Resource Group List
> Add a New Media Resource Group List.
Assign the San Jose MRG (MRG-SJ) to the San Jose MRGL (MRGL-SJ).
Assign the RTP MRG (MRG-RTP) to the RTP MRGL (MRGL-RTP).
Before you verify this configuration, you must assign the media resource group
lists (MRGLs) to the IP phones in the phone configurations. Refer to these documents
for more information:
In order to verify that devices use their assigned
resources, conference three IP phones across the two sites to make sure they
use G.711 and G.729. For example, in RTP call and RTP phone then conference
to a San Jose phone, and execute the show dspfarm dsp active command.
RTP#show dspfarm dsp active
SLOT DSP VERSION STATUS CHNL USE TYPE RSC_ID BRIDGE_ID PKTS_TXED PKTS_RXED
1 5 1.0.6 UP 1 USED conf 1 6 45559 45554
1 5 1.0.6 UP 1 USED conf 1 7 45559 45557
1 5 1.0.6 UP 1 USED conf 1 8 44959 44949
Total number of DSPFARM DSP channel(s) 1
This output shows an active conference between 3 phones. The initiator is an
IP Phone at the RTP site. Notice the three (3) active DSP sessions on the RTP