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The CUCM supports hardware and software conference bridges.
The software-based conference bridge, implemented as a CUCM service, supports only
conferences, using a single audio codec (G.711 or Cisco wideband).
V
IP
IP
PSTN
Annunciator
GW
Audio Signaling
V
IP
IP
PSTN
Integrated
MOH Server
GW
MOH Stream
MOH
Audio Signaling
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Some hardware conference bridges can support multiple low bit-rate (LBR) stream types
such as G.729, Global System for Mobile Communications (GSM), G.723, and iLBC. A
mixed-mode conference is a conference in which multiple audio codecs are used for different
audio streams. A mixed-mode conference bridge has the added burden of transcoding
the RTP bearer streams. Mixed-mode conferences limit the number of conference participants
and active conferences based on the capabilities of the hardware. There are multiple
hardware conference bridge families that should be investigated.
Software conferencing scalability is limited by the server platform CUCM is running on.
Conferencing capabilities of the server are throttled by default because it is assumed that
CUCM will be running call processing co-resident while providing conferencing capabilities.
The number of streams can be tuned up to 64 ad hoc conference participants and 128
meet-me conference participants on a standalone server (dependent on the server hardware
platform). A standalone server is dedicated to providing services to the CUCM, but it never
performs call processing (call setup and teardown).
A hardware conference bridge can support multiple LBR audio stream types, including
G.729, GSM, G.723, and iLBC.
All conference bridges that are under the control of CUCM currently use SCCP to
communicate with CUCM.
CUCM allocates a conference bridge from a conferencing resource that is registered with
the CUCM cluster. Both hardware and software conferencing resources can register with
CUCM at the same time, and CUCM can allocate conference bridges from either resource.
CUCM does not distinguish between these types of conference bridges when it processes
conference allocation requests.
The number of individual conferences and maximum number of participants per
conference varies by resource.
NOTE Hardware conference capabilities are well documented in the CUCM Solution
Reference Network Design Guide available at http://www.cisco.com/go/srnd. The DSP
Calculator should also be used when designing a solution involving hardware media
resources. As mentioned previously, the DSP Calculator is available at http://
www.cisco.com/go/dspcalculator.
376 Chapter 15: Media Resources
Cisco Conference Bridge Hardware
The following types of hardware conference bridge resources may be used on a CUCM
system:
■ Cisco Conference Bridge Hardware (Cisco Catalyst WS-X6608-T1 and WS-X6608-E1)
■ Cisco IOS Conference Bridge (Cisco NM-HDV)
■ Cisco Conference Bridge (Cisco WS-SVC-CMM and WS-SVC-CMM-ACT)
■ Cisco IOS Enhanced Conference Bridge (Cisco NM-HDV2, NM-HD-1V/2V/2VE,
PVDM2)
■ Cisco Video Conference Bridge (CUVC-3510 or 3540)
Cisco Conference Bridge Hardware (Cisco Catalyst WS-X6608-T1 and WS-X6608-E1)
This hardware has eight DSPs that are physically associated to each port, and there are eight
ports per card. The 6608 module is supported only in the Catalyst operating system of the
6500 series switch.
Configuration of the DSPs is at the port level, so all DSPs associated to a port perform the
same function.
Conference bridges may have up to 32 participants, and each port supports 32 conference
bridges.
For conferences with G.711 or G.723, there may be 32 conferences per port. If G.729 calls
are used, there may be 24 conferences per port. The 6608-T1/E1 gateway module is end of
sale (EoS).
Cisco IOS Conference Bridge (Cisco NM-HDV and 1700 Series Routers)
This hardware uses the PVDM-256K-type modules that are based on the C549 DSP
chipset. Conferences using this hardware provide bridges that allow up to six participants
in a single bridge.
The resources are configured per DSP for conference bridges.
The NM-HDV may have up to four PVDM-256K modules, whereas the Cisco 1700 series
routers may have one or two PVDM-256K modules.
Each DSP provides a single conference bridge that can accept G.711 or G.729 calls.
The Cisco 1751 is limited to 5 conference calls per chassis, and the Cisco 1760 can support
20 conference calls per chassis.
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Any PVDM2-based hardware, such as the NM-HDV2, may be used simultaneously in a
single chassis for voice termination but may not be used simultaneously for other media
resource functionality. The DSPs based on PVDM-256K and PVDM2 have different DSP
farm configurations, and only one may be configured in a router at a time.
Cisco Conference Bridge (Cisco WS-SVC-CMM-ACT)
This Cisco Catalyst-based hardware provides DSP resources that may provide conference
bridges of up to 32 participants per bridge.
Each module contains 4 DSPs that are individually configurable, and each DSP can support
32 conference bridges.
The G.711 and G.729 codecs are supported on these conference bridges without extra
transcoder resources. However, transcoder resources are necessary if other codecs are used.
Cisco IOS Enhanced Conference Bridge (Cisco NM-HDV2, NM-HD-1V/2V/2VE, 2800
Series, and 3800 Series Routers)
Based on the Texas Instruments (TI) C5510 DSP chipset, the NM-HDV2 and the router
chassis use the PVDM2 (Packet Voice DSP Modules - 2nd generation) modules for
providing DSPs.
DSPs on PVDM2 hardware are configured individually as voice termination, conferencing,
media termination, or transcoding resources. The DSPs on a single PVDM may be used
as different resource types. Allocate DSPs to voice termination first, and then to other
functionality as needed.
The NM-HDV2 (high-density voice) has four slots that will accept PVDM2 modules in any
combination. The other network modules have fixed numbers of DSPs.
A conference based on these DSPs allows a maximum of eight participants. When a
conference begins, all eight positions are reserved at that time. This means that unused
DSP resources on the same DSP chip are not available for other conferences.
The PVDM2-8 is listed as having a DSP because it has a DSP that has half the processing
capacity of the PVDM2-16. If the DSP on a PVDM2-8 is configured for G.711, it can
provide (0.5 x 8) bridges/DSP = 4 conference bridges. PVDM2 modules are available in 8,
16, 32, 48, or 64 quantities. The number of resources uses a divisor of 16. A PVDM2-64
has 64/8, or 8 DSP resources, which will allow up to 64 conferences with 8 conference
participants in each conference. The PVDM2 I/O limits the number of conference streams
in this scenario because 512 (64 × 8) audio streams are possible with 64 conferences of 8
conference participants.
378 Chapter 15: Media Resources
A DSP farm is a configuration parameter in Cisco IOS that specifies which codecs are
supported for the DSPs that are working together (farming). A DSP farm that is configured
for conferencing for G.711 provides 8 conferences. When configured to accept both G.711
and G.729 calls, a single DSP provides two conferences because it is also reserving its
resources for performing transcoding of streams.
The I/O of an NM-HDV2 is limited to 400 streams, so ensure that the number of conference
resources allocated does not cause this limit to be exceeded. If G.711 conferences are
configured, no more than 6 DSPs (total of 48 conferences with 8 participants each) should
be allocated per NM because 48 × 8 participants = 384 streams. If all conferencing is
configured for both G.711 and G.729 codecs, each DSP provides only two conferences
of eight participants each. In this case, it is possible to populate the network module (NM)
fully and configure it with 16 DSPs (PVDM2-64) because there can only be 2 conferences
with 8 participants (16) in each of the 16 DSPs (16 × 16 = 256 streams).
Conferences cannot natively accept calls using the GSM codec. A transcoder must be
provided separately for these calls to participate in a conference.
Meet-me conferences allow users to dial in to a conference. Ad hoc conferences allow the
conference controller to add specific participants to the conference.
Meet-me conferences require that a range of directory numbers (DN) be allocated for
exclusive use of the conference. When a meet-me conference is set up, the conference
controller chooses a DN and advertises it to members of the group. The users call the
DN to join the conference after the conference controller has set up the bridge using the
MeetMe softkey.
Ad hoc conferences comprise two types: basic and advanced. In basic ad hoc conferencing,
the originator of the conference acts as the controller of the conference and is the only
participant who can add or remove other participants.
In advanced ad hoc conferencing, any participant can add or remove other participants; that
capability is not limited to the originator of the conference. Advanced ad hoc conferencing
also allows linking multiple ad hoc conferences. Set the Advanced Ad Hoc Conference
Enabled cluster-wide service parameter to True to gain access to advanced ad hoc
conferencing. Advanced ad hoc conferencing is also referred to as conference chaining.
Conferencing 379
Conferencing Media Resource Configuration
The following steps are required to configure media resources:
1. Configure software conference media resources (if desired).
a. Enable the IP Voice Media Streaming application service.
b. Configure IP Voice Media Streaming application service parameters.
c. Configure desired software conferencing media resources.
2. Implement hardware conference media resources (if desired).
a. Configure hardware media resources in CUCM.
b. Configure hardware media resources in Cisco IOS.
c. Verify that hardware media resources are registered with CUCM.
The Cisco IP Voice Media Streaming application service is activated in Cisco Unified
Serviceability at Tools > Service Activation. At the top of the Service Activation window,
the server on which services should be activated or deactivated has to be selected. After
selecting the server, check the IP Voice Media Streaming App check box (Figure 15-7)
and click Save to activate the service.
The Cisco IPVMS parameters are accessible via the CUCM Administration, System >
Service Parameters. The following two conference bridge service parameters are
illustrated in Figure 15-8:
■ Call Count: This parameter specifies the maximum number of conference participants
that the conference bridge will support. Increasing this value above the recommended
default might cause performance degradation on a CUCM server that is also performing
call processing (co-resident). If this value needs to be tuned above the default,
consider installing the Cisco IPVMS on a standalone server. Alternatively, hardware
conferencing or a version of Cisco MeetingPlace can be used to offload conferencing
processing from the call-processing server. The configurable range is 0 to 256, and the
default is 48.
■ Run Flag: This parameter determines whether the conference bridge functionality of
the Cisco IPVMS is enabled. Valid values specify True (enabled) or False. The default
is True. All media resources are turned on by default when the Cisco IPVMS is
activated. Each media service can be turned on or off individually via the service
parameters or MoH server configuration.
380 Chapter 15: Media Resources
Figure 15-7 IP Voice Media Streaming Application Service Activation
Figure 15-8 IP Voice Media Streaming Application Service Parameters
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Figure 15-9 shows the default configuration of a software conference resource. The only
configurable items are Name, Description, Device Pool, Common Device Configuration,
and Location.
Figure 15-9 IP Voice Media Streaming Application Service Parameters
When adding a hardware conference bridge in CUCM, the type of conference bridge must
match the hardware family used. The IOS Enhanced Conference Bridge used in Figure 15-9
represents an NM-HDV2 or NM-HD-1V/2V/2VE, as discussed earlier in this chapter. This
particular type of conference bridge is configured by name, which must match between
CUCM and the Cisco IOS router.
To add a hardware conference bridge, navigate to Media Resources > Conference Bridge
and click the Add New button. The Conference Bridge Configuration window displays.
Enter the appropriate settings for that particular conference bridge and click Save. Figure
15-9 is based on a Cisco IOS Enhanced Conference Bridge configuration. Configurable
parameters vary by platform.
■ Conference Bridge Type: Choose Cisco IOS Enhanced Conference Bridge.
■ Conference Bridge Name: Enter a name for the conference bridge. The name must
match the name of the conference media resource as configured at the Cisco IOS router.
NOTE The CUCM software conferencing media resource supports only the G.711 and
Cisco wideband audio codecs. A hardware conference bridge or transcoder is necessary
to allow devices that use other audio codecs to participate in a conference.
382 Chapter 15: Media Resources
■ Device Pool: Choose a device pool. Best practice is to configure a separate device pool
dedicated to media resources. A good naming convention recommendation is
Media_Resources_DP.
■ Common Device Configuration: Choose the common device configuration to assign
to the conference bridge. The common device configuration includes attributes such as
MoH audio source.
■ Location: Choose the appropriate location for this conference bridge to enforce call
admission control (CAC). The location specifies the total bandwidth that is available
for calls to and from this location. A location setting of Hub_None means that the
Locations feature does not keep track of the bandwidth that this conference bridge
consumes. CAC is covered in more detail in Cisco IP Telephony Part 2.
■ Device Security Mode: This field displays for Cisco IOS Enhanced Conference Bridge
because only this audio conference bridge supports secure encrypted conferencing starting
in CUCM Version 6.0. If choosing Non Secure Conference Bridge, the nonsecure
conference establishes a TCP port connection to CUCM on port 2000. Ensure this setting
matches the security setting on the conference bridge; otherwise, the call will fail.
The Encrypted Conference Bridge setting supports the secure conference feature. Refer
to the CUCM Security Guide for secure conference bridge configuration procedures.
Figure 15-10 Cisco IOS Enhanced Conference Bridge Configuration
NOTE The name of the Cisco IOS Enhanced Conference Bridge configured in CUCM
must match the name of the conference bridge configured in the Cisco IOS router. The
name is case sensitive. Good naming conventions should be used to easily identify the
component. Prefix CFB (conference bridge), and then use a burned-in MAC address of
the router. CFB012345012345 is an example of a hardware conference bridge in a router
where the MAC address of 012345012345 is burned into the Gigabit Ethernet controller.
Conferencing 383
Example 15-1 is a configuration of a Cisco IOS Enhanced Conference Bridge. Each
command is explained following the configuration example.
■ dspfarm (DSP farm): To enable DSP farm service, use the dspfarm command in
global configuration mode. The DSP farm service is disabled by default.
■ dsp services dspfarm: To enable DSP farm services for a particular voice network
module, use the dsp services dspfarm command.
■ sccp local: To select the local interface that SCCP applications (transcoding and
conferencing) use to register with CUCM, use the sccp local command in global
configuration mode.
■ sccp ccm: To add a CUCM server to the list of available servers and set various
parameters, including IP address or DNS name, port number, and version number, use
the sccp ccm command in global configuration mode.
■ sccp: To enable the SCCP protocol and its related applications (transcoding and
conferencing), use the sccp command in global configuration mode.
■ sccp ccm group: To create a CUCM group and enter SCCP CUCM configuration
mode, use the sccp ccm group command in global configuration mode.
■ associate ccm: To associate a CUCM with a CUCM group and establish its priority
within the group, use the associate ccm command in SCCP CUCM configuration mode.
Example 15-1 Cisco IOS Configuration
voice-card 0
dspfarm
dsp services dspfarm
sccp local FastEthernet0/0.72
sccp ccm 10.1.1.1 identifier 1 version 6.0
sccp
sccp ccm group 1
associate ccm 1 priority 1
associate profile 1 register CFB001B0CC250F8
dspfarm profile 1 conference
codec g711ulaw
codec g711alaw
codec g729ar8
codec g729abr8
maximum sessions 2
associate application SCCP
no shutdown
384 Chapter 15: Media Resources
■ associate profile: To associate a DSP farm profile with a CUCM group, use the
associate profile command in SCCP CUCM configuration mode.
■ dspfarm profile: To enter DSP farm profile configuration mode and define a profile for
DSP farm services, use the dspfarm profile command in global configuration mode.
■ codec (DSP): To specify call density and codec complexity based on a particular codec
standard, use the codec command in DSP interface DSP farm configuration mode.
■ associate application sccp: To associate SCCP to the DSP farm profile, use the
associate application sccp command in DSP farm profile configuration mode.
■ maximum sessions (DSP farm profile): To specify the maximum number of sessions
that are supported by the profile, use the maximum sessions command in DSP farm
profile configuration mode.
■ no shutdown: If you fail to use the no shutdown command, the DSP farm profile will
display in the gateway but fail to operate.
To verify the Cisco IOS media resource configuration, use the show commands
demonstrated in Example 15-2.
Example 15-2 Verifying Cisco IOS Media Resource Configuration
show sccp
SCCP Admin State: UP
Gateway IP Address: 10.1.1.101, Port Number: 2000
IP Precedence: 5
User Masked Codec list: None
Call Manager: 10.1.1.1, Port Number: 2000
Priority: N/A, Version: 6.0, Identifier: 1
Conferencing Oper State: ACTIVE
- Cause Code: NONE
Active Call Manager: 10.1.1.1, Port Number: 2000
TCP Link Status: CONNECTED, Profile Identifier: 1
Reported Max Streams: 16, Reported Max OOS Streams: 0
Supported Codec: g711ulaw, Maximum Packetization Period: 30
Supported Codec: g711alaw, Maximum Packetization Period: 30
Supported Codec: g729ar8, Maximum Packetization Period: 60
Supported Codec: g729abr8, Maximum Packetization Period: 60
Supported Codec: g729r8, Maximum Packetization Period: 60
Supported Codec: g729br8, Maximum Packetization Period: 60
Supported Codec: rfc2833 dtmf, Maximum Packetization Period: 30
Supported Codec: rfc2833 pass-thru, Maximum Packetization Period: 30
Supported Codec: inband-dtmf to rfc2833 conversion, Maximum Packetization Period: 30
10.1.1.101
10.1.1.1
6.0
10.1.1.1
CONNECTED
Conferencing 385
Various CUCM service parameters are related to conferencing. The following conferencing
options should be considered when leveraging the conferencing features of CUCM:
■ Suppress Music on Hold to Conference Bridge: This parameter determines whether
MoH plays to a conference when a conference participant places the conference on
hold. Valid values specify True (the system does not play MoH to the conference when
a conference participant presses the Hold button) or False. The default is True.
■ Drop Ad Hoc Conference: This parameter determines how an ad hoc conference terminates.
This is an important toll-fraud prevention setting, because inside facilitators
can set up a conference call to expensive international numbers and then drop out of
show sccp ccm group 1
CCM Group Identifier: 1
Description: None
Binded Interface: NONE, IP Address: NONE
Associated CCM Id: 1, Priority in this CCM Group: 1
Associated Profile: 1, Registration Name: CFB001B0CC250F8
Registration Retries: 3, Registration Timeout: 10 sec
Keepalive Retries: 3, Keepalive Timeout: 30 sec
CCM Connect Retries: 3, CCM Connect Interval: 10 sec
Switchover Method: GRACEFUL,Switchback Method: GRACEFUL_GUARD
Switchback Interval: 10 sec, Switchback Timeout: 7200 sec
Signaling DSCP value: cs3, Audio DSCP value: ef
show dspfarm profile 1
Dspfarm Profile Configuration
Profile ID = 1, Service = CONFERENCING, Resource ID = 1
Profile Description :
Profile Admin State : UP
Profile Operation State : ACTIVE
Application : SCCP Status : ASSOCIATED
Resource Provider : FLEX_DSPRM Status : UP
Number of Resource Configured : 2
Number of Resource Available : 2
Codec Configuration
Codec : g711ulaw, Maximum Packetization Period : 30 , Transcoder: Not Required
Codec : g711alaw, Maximum Packetization Period : 30 , Transcoder: Not Required
Codec : g729ar8, Maximum Packetization Period : 60 , Transcoder: Not Required
Codec : g729abr8, Maximum Packetization Period : 60 , Transcoder: Not Required
Codec : g729r8, Maximum Packetization Period : 60 , Transcoder: Not Required
Codec : g729br8, Maximum Packetization Period : 60 , Transcoder: Not Required
Example 15-2 Verifying Cisco IOS Media Resource Configuration (Continued)
1 1 CONFERENCING
386 Chapter 15: Media Resources
the call. Without the conference controller, international tariffs are billed back to the
company in which the conference call was set up. Valid values are as follows:
—Never (default): The conference remains active after the conference
controller and all on-net parties hang up. This default setting could result
in potential toll fraud.
—When Conference Controller Leaves: Terminate the conference when the
conference controller hangs up.
—When No On-Net Parties Remain in the Conference: Terminate the
conference when there are no on-net parties remaining in the conference.
This distinction is important because the conference controller might
have to drop out of the call, but other business partners on the call should
continue the conference. The When Conference Controller Leaves option
would hang up the call when the conference controller left the
conference.
■ Advanced Ad Hoc Conference Enabled: This parameter determines whether
advanced ad hoc conference features are enabled. Advanced ad hoc conference
features include the ability for conference participants other than the conference
controller to add new participants to an existing ad hoc conference (conference
chaining); the ability for any noncontroller conference participant to drop other
participants from the conference via the ConfList and RmLstC softkeys; and whether
ad hoc conferences can be linked using features such as conference, join, direct
transfer, and transfer. Valid values specify True (allow advanced ad hoc conference
features) or False. The default is False.
■ Nonlinear Ad Hoc Conference Linking Enabled: This parameter determines
whether more than two ad hoc conferences can be linked directly to an ad hoc
conference in a nonlinear fashion. Nonlinear conference linking occurs when three
or more ad hoc conferences are linked directly to one other ad hoc conference. Linear
conference linking occurs when one or two ad hoc conferences are linked directly
to one other ad hoc conference. For this parameter to work, the Advanced Ad Hoc
Conference Enabled service parameter must be set to True. Valid values specify True
(allow nonlinear conference linking so that three or more ad hoc conferences can be
linked to a single other conference) or False. The default is False. The Advanced Ad
Hoc Conference Enabled service parameter must be set to True for the Nonlinear Ad
Hoc Conference Linking Enabled service parameter to work.
■ Maximum Ad Hoc Conference: This parameter specifies the maximum number of
participants who are allowed in a single ad hoc conference. The value of this field
depends on the capabilities of the software/hardware conference bridge. The maximum
number of conference bridge participants for typical conference bridges follow:
Conferencing 387
Software, 64; Cisco Catalyst WS-X6608, 16; Cisco Catalyst 4000, 16; and NM-HDV,
6. Setting this value above the maximum capacity of the conference resource will result
in failed entrance to a conference bridge if more ports than the specific conference
bridge configuration allows are added. The range is 3 to 64. The default is 4.
■ Maximum Meet-Me Conference Unicast: This parameter specifies the maximum
number of participants that are allowed in a single meet-me conference. The value of
this field depends on the capabilities of the software/hardware conference bridge. A
software conference bridge is capable of conferencing up to 128 participants. When a
conference is created, the system automatically reserves a minimum of three streams,
so specifying a value less than 3 allows a maximum of three participants. The range is
1 to 128. The default is 4.
Meet-Me Conference Configuration
To add a range of numbers to be used for meet-me conferences in CUCM Administration,
navigate to Call Routing > Meet-Me Number/Pattern and click Add New. Configure the
new pattern with the following data:
■ Directory Number or Pattern: Enter a meet-me number or number range.
■ Description: Enter up to 30 alphanumeric characters for a description of the meet-me
number.
■ Partition: To use a partition to restrict access to the meet-me/number pattern, choose
the desired partition from the drop-down list.
■ Minimum Security Level: Choose the minimum meet-me conference security level
for this meet-me number or pattern from the drop-down list:
—ChooseAuthenticated to block participants with nonsecure phones from
joining the conference.
—Choose Encrypted to block participants with authenticated or nonsecure
phones from joining the conference.
—Choose Non Secure to allow all participants to join the conference.
Figure 15-11 shows a meet-me range of 100 numbers beginning with 4500 and ending with
4599. The numbers are not in a partition, which will allow any phone to set up a meet-me
bridge by clicking the Meet-Me softkey and dialing one of the numbers in the meet-me
number range. Subsequent meeting members will need to dial only the number of the
bridge.