SIP vs H.323 on Codecs with VCS...reasons for enabling both?

Douglas Baggett · ‎09-05-2013

I have a bunch of MXP and C series codecs (along with Jabber Video clients) on my network. They all use VCS-C and VCS-E SIP for registrar and gatekeeper functionality (along with internetworking between protocols).

Given the VCS does the translation between H.323 and SIP, why have both enabled on our Codecs?

I understand that given the search rules, one or the other protocol will be used first depending on what protocol the originating incoming call is.

Do sites normally enable both protocols on codecs where a VCS-C and VCS-E is deployed? Or do people choose one protocol and just leave the other off? I understand there are BIG differences in how the protocols work and what you can do with managing systems, but I thought I'd ask to get an idea as to what other people were doing.

thanks

Paulo Souza · ‎09-05-2013

Hi Douglas,

Normally, I keep both protocols enable when I have to communicate Cisco devices with third party systems, mainly when you have VCSe and make and receive calls from internet (where you find all sorts of endpoints). In this case, I use both protocols to avoid interworking in VCS, because interworking feature of VCS has some limitations and does not work well with some third party devices, mainly the old devices.

For example, somtime ago, I took a case where and old polycom endpoint rebooted everytime it called TP Server via VCS with interworking going on, without interowking the problem did not occur.

When I have an enviroment with just Cisco endpoints without VCSe/Internet, I normally keep one single protocol, I like to use only SIP when there are CTS endpints and CUCM involved + Tandberg products, but I like to use only H323 when there are only Tandberg endpoints and VCS involved.

Regards

Paulo Souza

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Douglas Baggett · ‎09-05-2013

Somewhere the VCS engineer/programmer responsible for interworking is crying

If you keep both turned on, which do you prefer in your search rules? Would you rather it try H.323 first or SIP first?

I have a customer with an Edge 95MXP running version 7 of the software (I'm not sure you can even purchase a maintenance agreement to get the latest software for that unit) and he reports that a remote C series calls his unit directly it crashes the MXP. I'm thinking that switching it over to SIP only might get around the problem.

Paulo Souza · ‎09-05-2013

If you keep both turned on, which do you prefer in your search rules? Would you rather it try H.323 first or SIP first?

That is the point! I don't register the endpoint using both protocols and then choose one of them as first option, in fact, I enable both protocols and I configure the dial plan to achieve this goal: If an endpoint dialls using H323 protocol, I route the call using H323, If it dialls SIP, I route the calls using SIP.

Do you see? There is no preferred protocol, I route the calls trying to avoid interworking as long as I can.

However, as I stated before, I normally do this only when having third party devices that doesn't work well with interworking, otherwise, when only having Cisco endpoints, I prefer to keep one single protocol.

I know that the document "VCS Basic Configuration" suggest you to keep both protocols and then using the search rules to use one of them as preferred. However, you must to realize that it is a basic deployment, and it is only an configuration example, there are too many ways to setup your dial plan. I have my way, my way is that.

I like VCS interowrking feature, it works very well. In my opinion better than CUBE. But there is some blind points, that's why I prefer to avoid it in some scenarios.

=)

Paulo Souza

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Jens Didriksen · ‎09-06-2013

I completely agree with Paulo, and we use both SIP and H.323.

Both protocols are enabled on all of our end-points as we need to support not only the enterprise version of JabberVideo, but also the "free" jabber.com version and whatever SIP clients external sites wants to use - as long as they can interop.

In some of these cases SIP-H323 interworking just won't work, the calls have to be SIP<-->SIP.

/jens

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Wayne DeNardi · ‎09-05-2013

Douglas Baggett wrote:

I'm not sure you can even purchase a maintenance agreement to get the latest software for that unit) and he reports that a remote C series calls his unit directly it crashes the MXP

According to the End-of-Sale and End-of-Live Announcement (http://www.cisco.com/en/US/prod/collateral/ps7060/ps11304/ps11313/ps11382/end_of_life_notice_c51-720894.html), you should be able to purchase a service contrct for the Edge 95 MXP up until 14 May 2014. You'd then be able to get it up to a recent version (latest is 9.3.1) rather than the old version 7.

We have a bunch of 95s running 9.3.1 which happily talk to all of our C series codecs using H.323 or SIP.

Wayne

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Douglas Baggett · ‎09-06-2013

Thank you! That is very helpful. I'll pass that along.

dortewillemann911 · ‎09-06-2013

Hellu Douglas,

To answer your kuestion,

I have a customer with an Edge 95MXP running version 7 of the software (I'm not sure you can even purchase a maintenance agreement to get the latest software for that unit) and he reports that a remote C series calls his unit directly it crashes the MXP. I'm thinking that switching it over to SIP only might get around the problem.

you can try changng the protuculs from h323 to Sip and vice versa but i dont thing that will help.

MXP on F7 is veryy uld software. When C series culls yor MXP, the codecs negutiation during SDP (sip case)

H245 ( h323 case) causes your MXP to crash. becauses negutiation fails and MXP cannot handle advance audio

video codecs of C series.

Things you can do to fix this:

1. best would be to upgrade MXP to F9.xx

2. enable capset filter on C series, that will filter the new codecs and only let old codecs to be negotiated.

3.Last thing to do > check C series codecs software if its on TC 5 or 6 try to downgrade it to 4.

capset filter command

Example:

To force H.261 -> disable H.264 and H.263

xConfig Experimental CapsetFilter: H.264RCDO;H.264NIL;H.263;H.263PP

Codec means software codecs like G711, h264 etc .

I think this should Sulve your issue.

I thank you

Dorte.....

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Douglas Baggett · ‎09-09-2013

Actually, that is an interesting approach. I'll think about that and try it.

thanks!

Jens Didriksen · ‎09-06-2013

Douglas Baggett wrote:

I have a customer with an Edge 95MXP running version 7 of the software (I'm not sure you can even purchase a maintenance agreement to get the latest software for that unit)

You don't need a service contract to upgrade to F9.x, see my post here:

https://supportforums.cisco.com/message/3971210#3971210

/jens

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Alok Jaiswal · ‎09-05-2013

Douglas,

There are so many things to choose a protocol. But i prefer sip as it provides better interop with third party products.

-Alok

Patrick Sparkman · ‎09-06-2013

Douglas -

Something to consider to get a software upgrade take a look at the following.

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110831-tandberg