CUCM IM and P Design - DNS SRV -

[Nicolas MICHEL]

Hey guys.

I would like to design a CUCM IM and P infrastructure for my customer. High availability is mandatory for my customer and here is what I found from the documentation:

Configure SIP Trunk for IM and Presence Service

If high availability is configured for the IM and Presence cluster, multiple entries should be entered in the Dotted IP Address or FQDN to identify the various nodes in the cluster. DNS SRV cannot be used for an IM and Presence cluster if high availability is configured.

So SRV record can't be used for an IM and P cluster.

Now if I want to configure a presence gateway on the CUCM IM and P, the configuration guide says that we must configure a CUCM as a presence gateway to enable SIP connection:

The problem is that I cannot configure 2 or more CUCM Presence gateways ... and for that I have to use a DNS SRV.

But I can't use an DNS SRV because I am using high availability ... This is a chicken and egg problem to me :)

Does someone has a recommendation please ? 

Thanks guys :)

[Jonathan Schulenberg]

On the SIP Trunk destination section, add both hosts of the sub-cluster. 

[Nicolas MICHEL]

Hi Jonathan !

This is exactly what I did on the CUCM side in order to have high availability.

What can I do on the CUCM IM and P side ? This I can't use DNS SRV because of the HA and since I the server won't let me configure 2 CUCM Presence gateway :)

Thanks :)

Nicolas

[Jonathan Schulenberg · Accepted solution]

Actually, the config guide allows DNS SRV on the Presence Gateway config of the IM&P servers:

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/im_presence/configAdminGuide/10_5_1/CUP0_BK_CE43108E_00_config-admin-guide-imp-105/CUP0_BK_CE43108E_00_config-admin-guide-imp-105_chapter_0111.html#d54883e741a1635

It appears they are only disallowing SRV in the CCM to IM&P SIP Proxy, not the other way around.

[Nicolas MICHEL]

I will try that for sure

Thanks a lot Jonathan !

Nicolas