SIP Trunking

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Aug 24th, 2010
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I'm running Call Manager 6 and  I thought about using sip trunking.

I keep hearing a lot of good things about but I'm not sure.

What am i gaining but using sip trunking? Does it increase my bandwidth at my remote sites?

I'm using G7.29 and I'm not sure if sip trunking uses a different protocol?

What are the disadvantages and advantages of sip trunking?

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Aaron Harrison Tue, 08/24/2010 - 10:08
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Hi Jay


If you don't know what a SIP trunk is, you don't need one :-)


Basically SIP is a method of setting up/managing connections. You would typically use it between two seperate call control systems (i.e. between CCM and another IP capable PBX), not between parts of a CCM system (i.e. not between a remote site and a head office).


If you use a SIP trunk, the actual voice conversations still use G729 or G711 (or some other protocol) for the actual RTP. So there's no tangible effect on the per-call bandwidth.


Regards


Aaron


Please rate helpful posts...

philip.e.denton Wed, 08/25/2010 - 06:46
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You would typically use it between two seperate call control systems (i.e. between CCM and another IP capable PBX), not between parts of a CCM system (i.e. not between a remote site and a head office).



Not true!  I just came off an enterprise deployment with 11000 phones spread across 700 sites and every remote site used SIP over an MPLS WAN for CM connectivity.  The customer felt that MGCP was not stable enough and had too much overhead.


Additionally, SIP is standards-based (as is H.323) whereas MGCP, the Cisco-created gateway control protocol, is proprietary.  This obviously allows easier interoperability with third-party devices.


SIP uses a client/server model with HTML-like control messages, making troubleshooting much easier than other protocols which use ambiguous raw hex error codes.


As far as endpoints goes, Cisco phones can run either SIP or SCCP but I don't believe the feature parity is there yet (so stick with SCCP).  The cool thing is SIP's interoperability allows you to play with third-party SIP phones in your CUCM environment if you'd like, but just remember that you won't get the same features as a SCCP-powered phone (yet).


There are many many more pluses and minuses to using SIP but those are the first that came to mind.  Just spend a few minutes Googling and you'll find plenty!

Aaron Harrison Wed, 08/25/2010 - 06:54
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So you're saying the original poster should switch to SIP?


As you say, phones don't have the feature parity except for those phones that don't have SCCP software available.


The title of the post was 'SIP Trunking'... since he's not mentioned any 'foreign' systems, I guess he could create SIP trunks to his gateways. Since his gateways are working just fine as far as we're aware... he should switch to SIP to save a few bytes of control traffic?


I did say 'typically'... SIP adoption for intracluster signalling in CCM has been slow, basically as there's little real benefit to switching.


Aaron

philip.e.denton Wed, 08/25/2010 - 08:11
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No, I'm not saying that at all.  The poster asked for advantages and disadvantages of SIP trunking so I threw some out there.  Everyone who posted before me had addressed SIP in the context of Inter-PBX communication so I just wanted to point out that it could be used for intra-PBX communication as well.


The unsolicited information about SIP endpoints was an added bonus

frlindse Tue, 08/24/2010 - 17:02
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The only real advantage to SIP vs. T1or analog is it allows you to utilize a single connection for voice, WAN, and INTERNET (depending on your service provider).  It is also a fast growing protocol for interop between different vendors equipment.

jazzeyb Sat, 12/10/2011 - 20:50
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The other advantage is  you save $400 per month per PRI (we do) by going SiP..

We are actually using intelepeer for SIP over Cisco backbone with ms Lync... We love their product and support.

Brian Bell - cto

wrar

pharden Mon, 05/16/2011 - 11:29
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Hey Jay We are now exploring SIP trunking. I have been adding up the savings and find incorporating voic, data over or MPLS will save ALOT of money. I am still tring to figuare out how to implment this. We have bids out for an RFQ my boss sent out. I hope to work closely with our vendor to accomplish this. I will try to keep you updated as i find out more about this.

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