[cisco-voip] curious - no DNS SRV for SIP trunk to IM&P in HA

Tue Jun 21 15:11:51 EDT 2016

omg. this. if ever i thought nothing could drive me crazy like secondary line forwarding. but this sure did. 

it turns out there is an internal bug that prevents the dashboard from presenting the correct information. there is no way to be sure that the SRV records you entered are correct at all. and no real documentation to stipulate the actual correct syntax. 

the documentation team refused to say anything was wrong. 

the TAC engineer showed that things worked without it. 

I ended up setting it to the FQDN of the publisher to get rid of any errors. 

ug. leeeeeee. 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

----- Original Message -----

From: "Anthony Holloway" <avholloway+cisco-voip at gmail.com> 
To: "Lelio Fulgenzi" <lelio at uoguelph.ca> 
Cc: "Brian Meade" <bmeade90 at vt.edu>, "Cisco VoIP Group" <cisco-voip at puck.nether.net> 
Sent: Tuesday, June 21, 2016 1:34:28 PM 
Subject: Re: [cisco-voip] curious - no DNS SRV for SIP trunk to IM&P in HA 

Resurrecting an old thread, because I hate when there's no closure to these topics. 

Whatever happened with your work on this? Was the TAC engineer correct, or incorrect in his "you don't even need a presence gateway." statement? 

Is CUCM supposed to be configured in DNS as UDP or TCP? There is conflicting documentation out in the wild. You, Lelio, Linked to both. 

Lastly, I just had a TAC case where I had SRV setup and it was working, and then all of the sudden it stopped working, so the TAC engineer just changed my entries back from SRV to straight up IP and it starting working again. No explanation of why SRV's were failing. 

I'm inclined to think that the solution doesn't get enough visibility to have anyone care enough to truly figure it out or fix it. Well, I'm trying to draw attention to it now. 

On Wed, Jan 20, 2016 at 12:01 PM, Lelio Fulgenzi < lelio at uoguelph.ca > wrote: 

So I've tried to get DNS SRV working on IM&P, namely the Presence Gateway configuration, so the DNS SRV record for the callmanager subscribers I want to use. 

It's not working. All attempts at research show that I should be able to do this: 

http://benmorgan.com.au/blog/cucm-and-imp-integration-with-srv-records/ 

http://www.netcraftsmen.com/using-dns-srv-records-for-cisco-cucm-and-cups/ 

http://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-im-presence-service/118590-config-cucm-00.html 

So I opened a case with the TAC to get some help. 

The TAC engineer has basically said, it's not even needed for the latest versions of IM&P it was for old CUPS versions. He said to simply point to my publisher. 

He showed me on his lab that he had no presence gateway configured at all, but yet, presence was updated on his jabber client. 

I'm flabbergasted. 

Are other people not using DNS SRV records for their Presence Gateway configuration at all? 

VERY weird. 

Lelio 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

From: "Lelio Fulgenzi" < lelio at uoguelph.ca > 
To: "Brian Meade" < bmeade90 at vt.edu > 
Cc: "Cisco VoIP Group" < cisco-voip at puck.nether.net > 
Sent: Tuesday, January 19, 2016 10:24:08 AM 

Subject: Re: [cisco-voip] curious - no DNS SRV for SIP trunk to IM&P in HA 

OK. Great. 

I'm just going through the process of setting up the SRV record instead of FQDN of callmanager on my lab cluster and it's not working. :( 

Will need to review... 

I'm using this as a guide, even though it's v11. 

http://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-im-presence-service/118590-config-cucm-00.html 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

From: "Brian Meade" < bmeade90 at vt.edu > 
To: "Lelio Fulgenzi" < lelio at uoguelph.ca > 
Cc: "Cisco VoIP Group" < cisco-voip at puck.nether.net > 
Sent: Tuesday, January 19, 2016 10:15:44 AM 
Subject: Re: [cisco-voip] curious - no DNS SRV for SIP trunk to IM&P in HA 

Yea, you would need your SRV to match the CM Group for the device pool. Or just choose run on all active nodes. Main ramification of that is making sure the other side can accept SIP messages from any of the nodes. 

On Tue, Jan 19, 2016 at 9:15 AM, Lelio Fulgenzi < lelio at uoguelph.ca > wrote: 

<blockquote>

Thanks Brian. 

I had to read the bug twice. It's the troubleshooter on CUPS, but it's testing what's configured on CUCM by the sounds of it. 

I think I will play it safe and use IP addresses on the CUCM configuration pointing to the HA CUPS pair. And on the CUPS server, I will go ahead an use an SRV record since I want to be able to point to more than one CUCM server. 

Another question arises though. I remember when playing with intercluster trunks, it had to be fully meshed, so all trunk members on one cluster had to point to all members on the other cluster, or calls would fail. 

Does a SIP trunk have to be fully meshed as well? 

For example, if the device pool of the SIP trunk includes subA, subB and subC, do I have to make sure that the SRV records I'm using on the CUPS server have those three servers included? 

I was also considering checking off "make active on all nodes" - but I'm not sure of the ramifications of that. I'd have to probably write the SRV record properly so that the publisher is (never) used or used only as a last resort. 

Thanks! 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

From: "Brian Meade" < bmeade90 at vt.edu > 
To: "Lelio Fulgenzi" < lelio at uoguelph.ca > 
Cc: "Cisco VoIP Group" < cisco-voip at puck.nether.net > 
Sent: Monday, January 18, 2016 4:56:18 PM 
Subject: Re: [cisco-voip] curious - no DNS SRV for SIP trunk to IM&P in HA 

Looks like it may just be the CUPS Troubleshooter Tool doesn't know how to handle it- https://tools.cisco.com/bugsearch/bug/CSCue72366 

So it looks like it will work as an SRV but may fail in the troubleshooting tool. It looks like this was because IM&P/CUPS disn't support resolving SRVs until recently- https://tools.cisco.com/bugsearch/bug/CSCui67346 

On Mon, Jan 18, 2016 at 3:47 PM, Lelio Fulgenzi < lelio at uoguelph.ca > wrote: 

<blockquote>

Just reading through some documentation (see link below) and it states that when configuring the SIP trunk from CUCM to the IM&P cluster, I can not use DNS SRV records if I'm using HA. Tells you to use IP address or FQDN. 

Just wondering what others have thought about this. I'll go ahead and use IP address, but it struck me as odd. 

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/im_presence/configAdminGuide/9_1/CUP0_BK_C68AA046_00_config-admin-guide-imp-91/CUP0_BK_C68AA046_00_config-admin-guide-imp-91_chapter_0101.html#CUP0_TP_SBE6AFC1_00 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

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