Busyout and MGCP Vs H.323

[manuel.rouze]

Hi all,

Is it possible to busyout a voice-port with MGCP ?

The commands are available but, it does not seem to have any effect on the voice-port, and my PBX keeps sending calls on it even if I shut the busyout-monitored interface.

I think that's not supported for the moment, but it'll help if someone can confirm...

And give an approximative date for support...

In fact I'm actually testing H.323 and MGCP to decide which of the two we'll implement for a customer.

And even if MGCP is far easier to administrate, and manage CCM failover better (and give a distinctive internal/external ring), I discovered that there's some issues:

- limited interfaces support,

- heavier troubleshoot,

- MGCP release 0.1 (means that's not a definitive and stable release ?),

- no busyout,

- loss of isdn tuning and monitoring on the router,

- limited digit manipulation,

Any experiences out there ?

Thanks

Manuel.

[dweiner]

Well, I'll give some of these a shot -

- limited interfaces support,

True, there are some interfaces supported in H323 and not in MGCP (DID, E&M come to mind). Common PSTN interfaces are good for mgcp, though.

- heavier troubleshoot,

Not necessarily. You can still use the IOS debugs if you're used to them, but you can also see trace messages in the CallManager trace logs, and use the integrated Q931 translator in CallManager. There are very few commands to get mgcp going in the gateway - most configuration takes place in the CallManager GUI so, IMHO, makes it easier.

- MGCP release 0.1 (means that's not a definitive and stable release ?),

Though I'd normally agree with being shy about 0.x releases, I don't believe this is an issue. The MGCP messaging between CCM and MGCP routers is stable.

- no busyout,

You still have use of busyout commands, though you identify an issue. I have used busyout successfullty with mgcp gateways, though I don'tknow if that gets transferred to the PBX (i.e. yellow alarm). I don't have any news on that one.

- loss of isdn tuning and monitoring on the router,

Not that I know of. Which "tuning"? You can still enter commands for the voice port (x.x:23) to "tune". Lots of monitoring with the Admin Servicability monitor/Real-Time Monitor

- limited digit manipulation,

You have all the digit manipulation capabilities of CallManager - aka translation patterns. There are some things you can do with number expansion in an H323 gateway, but not much that I've seen.

To all of these I would add that mgcp gives you call survivability - call stays up if a callmanager server goes down, plus much more integration with your dial plan, CallManager GUI administration, simplified administration in the gateway. There would have to be some pretty specific circumstances to get me to go with H323.

My 2c

[manuel.rouze]

Thanks for your answers.

Regarding busyout, How did you have it working ?

Refering to this document http://www.cisco.com/en/US/products/hw/routers/ps259/products_data_sheet09186a00800921ed.html

I see that Local voice busyout and Advanced voice busyout are not supported on MGCP gateways...

My H.323 BRI link goes up or down according to the link-state of another port (which is busyout normal behaviour), but my MGCP E1 does not...

So my PBX keeps sending calls on the E1...

Any help ?

Thanks,

Manuel.

[dweiner]

The data sheet refers to busying out the trunks based on network congestion. I was talking about a forced busyout. We used, I believe, the "ds0 busyout dso-timeslot " command under "controller t1 xx" to busy out a range of timeslots. But, I'm not sure what the pbx side saw.

[manuel.rouze]

A forced busyout on an H.323-controlled voice-port shuts down the link between Gateway and PBX (Layer 1 down).

On a MGCP-controlled voice-port, the behaviour is different: a forced busyout actually shuts the voice-port, but not the link.

This is certainly because with CCM MGCP, the isdn L3 is terminated on the CCM??

I also tried to busy out the DSO : idem.

Result: the router does not acknowledge the calls received from the gateway and the call remains unanswered; but as the link is still up, the PBX keeps sending calls on it.

Hopefully, the MD110 PBX I use can re-route the call on another trunk after XXX failed tries...

But BUSYOUT is the kind of features H.323 handles far better than MGCP.

Cheers

Manuel.