Maximum Number of Conference Bridge Participants?

[Chin Jam]

In our environment we have Cisco IOS Enhanced Conference Bridges configured in CUCM.  We use a 2911 router for our voice gateway which has 2 x PVDM3 DSP DIMM with 32 Channels installed.

In CUCM Service Parameters > Conference Clusterwide Parameters we have the following set:

Maximum ad-hoc = 16
Maximum MeetMe = 16

I have read that 'Cisco IOS Enhanced Conference' bridges support up to 8 participants on a single call. I also read that the PVDM3 cards support up to:

• Up to 32 participants for G.711 conferences
  Up to 16 participants for G729/G729A/G.722 conferences

Our voice gateway supports both g711 and g729:

--------------------------------------------------------
Conferencing Oper State: ACTIVE - Cause Code: NONE
Active Call Manager: 10.10.7.11, Port Number: 2000
TCP Link Status: CONNECTED, Profile Identifier: 1
Reported Max Streams: 16, Reported Max OOS Streams: 0
Supported Codec: g729br8, Maximum Packetization Period: 60
Supported Codec: g729r8, Maximum Packetization Period: 60
Supported Codec: g729abr8, Maximum Packetization Period: 60
Supported Codec: g729ar8, Maximum Packetization Period: 60
Supported Codec: g711ulaw, Maximum Packetization Period: 30
Supported Codec: g711alaw, Maximum Packetization Period: 30
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
TLS : ENABLED
--------------------------------------------------------

My questions are:

1. What is the maximum number of participants that can join a conference call?
2. How many conferences can be active simultaneously?

Thanks and appreciate any insight.

[Jaime Valencia · Accepted solution]

For participants:

If using DSPs, maximum is whichever number is lower, either participants configuration on IOS for the dspfarm, or the CUCM parameter.

If using IPVMS, then it's just the CUCM parameters

Maximum number of conferences on DSP, whatever you set as maximum sessions.

On IPVMS, the number of streams configured for IPVMS as max / CUCM parameter = max conferences of that kind.

For IPVMS bear in mind that you subtract the parameter value from the maximum IPVMS streams for each conference and those resources are shared for ad-hoc, meet-me and conference now.

[Chin Jam]

Thanks for the assistance Jaime.

I see the following dspfarm config in the IOS:

===============================================
dspfarm profile 1 conference
codec g711alaw
codec g711ulaw
codec g729ar8
codec g729abr8
codec g729r8
codec g729br8
maximum sessions 2
conference-join custom-cptone CCAjointone
conference-leave custom-cptone CCAleavetone
associate application SCCP

telephony-service
sdspfarm conference mute-on 111 mute-off 222
sdspfarm units 2
sdspfarm tag 1 --------------
conference hardware
srst mode auto-provision none
srst ephone template 10
srst ephone description SRST Fallback : -----------
srst dn template 10
srst dn line-mode octo
max-ephones 42
max-dn 100
ip source-address 10.10.57.10 port 2000
max-redirect 12
calling-number initiator
service phone videoCapability 1
service phone ehookenable 1
service dnis overlay
service dnis dir-lookup
timeouts interdigit 5
system message ------------------
cnf-file location flash:
cnf-file perphone
time-zone 6
keepalive 30 auxiliary 4
max-conferences 8 gain -6
call-forward pattern .T
call-forward pattern 918003631675
moh enable-g711 "music-on-hold_10db.au"
multicast moh 239.1.1.1 port 16384 route ------------
dn-webedit
time-webedit
transfer-system full-consult dss
transfer-pattern .T
transfer-pattern 9.T
secondary-dialtone 9
fac standard
create cnf-files version-stamp Jan 01 2002 00:00:00
=======================

I'm not sure how to interpret this to determine the maximum number of participants and max number of simultaneous conferences?

[Jaime Valencia · Accepted solution]

Maximum participants for dspfarm if not configured is 8, and depends on codec complexity whether you can change it or not.

https://community.cisco.com/t5/ip-telephony-and-phones/pvdm2-32-maximum-conference-participants/td-p/1536914

Maximum number of conferences on DSP, see previous reply.

Overall number of maximum conferences will depend on available conference bridges, configuration of dspfarms, and CUCM parameters, there's no straight answer, you need to find that out from your system.

[Chin Jam]

Thanks again for the help and information.