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New Member

Codecs and "MTP Required"

Hi everybody,

I am working on CUCM v9.1.2 architecture with the following configuration

CODEC :

- Intra-region 1 HQ : G711/G722

- Intra-region 2 RemoteSite : G711/G722

- Inter-region 1 HQ / 2 RemoteSite : G729

Phones :

6945 with SIP + "MTP required" Checked (option needed for security issue)

Media Ressources :

1) Gateway 2825 v15.1.4.M7 (CFB, MTP, XCODE hardware activated)

2) CUCM (Software Ressources on dedicated server "Cisco IP Voice Media Streaming App")

My problem :

  1. When I make a call between 2 phones on the same region, using G722, it's working fine with "MTP required" enabled : OK
  2. When I make a call between 2 phones both regions, using G729, it's working fine without "MTP required" enabled : OK
  3. When I make a call between 2 phones both regions, using G729, it's failed with "MTP required" enabled : KO

Gateway 2825 has the following configuration :
#####################################################

sccp ccm group 1

associate ccm 1 priority 1

associate ccm 2 priority 2

associate profile 1 register CFB_HW_GWMEDIA1

associate profile 2 register MTP_HW_GWMEDIA1

associate profile 3 register XCODE_HW_GWMED1

registration retries 15

registration timeout 5

keepalive retries 7

keepalive timeout 20

connect retries 5

connect interval 30

switchback method graceful

switchback interval 120

!

dspfarm profile 3 transcode

codec g729abr8

codec g729ar8

codec g711alaw

codec g711ulaw

codec g729br8

codec g729r8

codec g722-64

maximum sessions 12

associate application SCCP

!

dspfarm profile 1 conference

codec g729br8

codec g729r8

codec g729abr8

codec g729ar8

codec g711alaw

codec g711ulaw

codec g722-64

maximum sessions 2

associate application SCCP

!

dspfarm profile 2 mtp

codec g711ulaw

maximum sessions hardware 12

associate application SCCP sccp ccm group 1
associate ccm 1 priority 1
associate ccm 2 priority 2
associate profile 1 register CFB_HW_GWMEDIA1
associate profile 2 register MTP_HW_GWMEDIA1
associate profile 3 register XCODE_HW_GWMED1
registration retries 15
registration timeout 5
keepalive retries 7
keepalive timeout 20
connect retries 5
connect interval 30
switchback method graceful
switchback interval 120
!
dspfarm profile 3 transcode
codec g729abr8
codec g729ar8
codec g711alaw
codec g711ulaw
codec g729br8
codec g729r8
codec g722-64
maximum sessions 12
associate application SCCP
!
dspfarm profile 1 conference
codec g729br8
codec g729r8
codec g729abr8
codec g729ar8
codec g711alaw
codec g711ulaw
codec g722-64
maximum sessions 2
associate application SCCP
!
dspfarm profile 2 mtp
codec g711ulaw
maximum sessions hardware 12
associate application SCCP

#####################################################

MTP dspfarm profil dont permit using g729 codec. This is normal?

Transcode should be used on the call 3), permitting call between 2 phones with g729 and g722 codec with "MTP required" checked?

Thank you for your help.

Resgards,

Pierre

  • IP Telephony
Everyone's tags (3)
1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Codecs and "MTP Required"

Hi Pierre,

As I see from your configuration, you have G711 codec defined in your MTP dspfarm config and you are using hardware sessions.

Try the following configuration for the MTP and I believe all you call scenarios should work:

dspfarm profile 2 mtp

no codec g711ulaw

codec g729r8

codec g729br8

codec g729abr8

codec g729ar8

maximum sessions software 500

associate application SCCP

no shut

If you use "max sessions software" command, you do not use the DSP resources and can have upto 500 sessions supported on the IOS gateway.

[check Table 27-2 of the following document:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_6_1/ccmsys/a05mtp.html#wpxref35934]

Now, for the G711 calls, you can either have another dspfarm configured or alternately, you can use the native software MTPs of the CUCM.

HTH.

Regards,

Saurabh

18 REPLIES
Hall of Fame Super Silver

Codecs and "MTP Required"

What security reason do you need the MTP on internal calls for?

Chris

New Member

Codecs and "MTP Required"

Dear Chris,

Thanks for your return.

MTP is required for internal calls in order to control call flow. With "MTP required" checked, you do not need to open flow in Firewall between phones dispatched in several VLANs.

Cisco Team has designed this specific architecture for 10 000 devices needing specifics security features.

Pierre

Hall of Fame Super Silver

Codecs and "MTP Required"

Wow, this is crazy, so every call will traverse an MTP, hopefully someone ran this trhough capacity calculation :-(

This sure sounds like fun to support. You may need to build software G711 and G729 seperate MTP dspfarm profiles and have them both available in the MRG/MRGL. Alternatively you may need to engage xcoders on some of the call flows.

HTH,

Chris

Cisco Employee

Codecs and "MTP Required"

Hi Pierre,

As I see from your configuration, you have G711 codec defined in your MTP dspfarm config and you are using hardware sessions.

Try the following configuration for the MTP and I believe all you call scenarios should work:

dspfarm profile 2 mtp

no codec g711ulaw

codec g729r8

codec g729br8

codec g729abr8

codec g729ar8

maximum sessions software 500

associate application SCCP

no shut

If you use "max sessions software" command, you do not use the DSP resources and can have upto 500 sessions supported on the IOS gateway.

[check Table 27-2 of the following document:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_6_1/ccmsys/a05mtp.html#wpxref35934]

Now, for the G711 calls, you can either have another dspfarm configured or alternately, you can use the native software MTPs of the CUCM.

HTH.

Regards,

Saurabh

Hall of Fame Super Silver

Codecs and "MTP Required"

MTP can be a single codec only, so either G711 or G729, if both are needed you will need to build seperate dspfarm profiles for each.

Chris

New Member

Codecs and "MTP Required"

Hi,

Chris, I confirm Cisco UC Sizing Tool has been used by Cisco Team. More than 6.000 PVDM3 ressources will be used.

When I create DSP profile for MTP sofware, I have the following return:

################################################################

GW-MEDIA-1(config-dspfarm-profile)#codec g729r8

GW-MEDIA-1(config-dspfarm-profile)#codec g729br8

Codec is already configured for the profile, it is not compatible

with codec being configured for MTP service

GW-MEDIA-1(config-dspfarm-profile)#codec g729abr8

Codec is already configured for the profile, it is not compatible

with codec being configured for MTP service

GW-MEDIA-1(config-dspfarm-profile)#codec g729ar8

################################################################

=> Chris, thx for your last update, it explain this "error".

I will test tomorrow this configuration with DSP profile for MTP sofware for G729 + hardware for G711.

I can't use MTP Software on CUCM due to capacity (MTP on dedicated Gateways needed).

Chris, can I used xcoders on Gateway when MTP hardware on Gateway need to use G729 codec ?

Regards,

Pierre

Hall of Fame Super Silver

Codecs and "MTP Required"

Sure, xcoders can only be hardware, MTPs can either be hardware or software IOS or software CUCM (not recommended).

HTH, please rate all useful posts!

Chris

New Member

Codecs and "MTP Required"

If I use MTP hardware, with 2 profiles g729 / G711, how can I translate call with hardware xcoders on the same Gateway ?

It is automatic ?

Sorry, I clic on "Correct Answer", it's a mistake. I can't cancel it for the moment.

Hall of Fame Super Silver

Codecs and "MTP Required"

These are all registered to CUCM, and CUCM engages them as needed based on allocation to MRGL/MRG.

HTH,

Chris

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