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New Member

MGCP or H323/SIP gateway?

Hi, I am setting up a new branch office where we will use a C2901 with PRI for PSTN connectivity for inbound dialing and SIP for outbound dialing, I plan to let phones in remote office to register to corp CUCM, each phone will have a local DID number. One obstacle I am facing is that the DID numbers we got from T1 PRI provider can not easily be stripped and mapped to internal directory numbers we set aside for the remote office(because conflicting with exsiting internal DNs), If I control the PRI via MGCP, as far as I understand, CUCM seems to only allow me to select the number of digits from the dialed number from PRI to keep. I am thinking to run SIP between corp CUCM and C2901, with C2901 IOS's powerful translation profile I can have much more flexibility to manipulate dialed digits. Will that work? or if I use MGCP, on CUCM can I have other way to manipulate more complicated dialed digits?

Thanks!

Everyone's tags (4)
4 ACCEPTED SOLUTIONS

Accepted Solutions
Bronze

Re: MGCP or H323/SIP gateway?

Hi,

Though H.323 provides more flexibility, you can achieve similar translations with MGCP GW registering with CUCM and configuring translation rules in CUCM on the basis of called number from PSTN.

Pls follow the following link which may help...

http://www.gossamer-threads.com/lists/cisco/nsp/97093

Alternatively, you can allow your IP phones register with CUCM, configure translations in your GW locally and register the GW as H.323 in CUCM. And you need to configure a dial peer pointing to CUCM for the translated called number range so that CUCM will provide signalling appropriately to establish the audio stream with respective IP phone at branch for the branch H.323 GW.

Regards...

-Ashok.

With best regards... Ashok ----------- Pls kindly rate if helpful or answered your question.
Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

You should always use H.323 or SIP.

MGCP has too many limitations, and is cumbersome to configure,

Silver

Re: MGCP or H323/SIP gateway?

I agree with Paolo,

Use H.323 or SIP.  MGCP can be flaky as well as being troublesome to set up.  You are likely going to be setting up SRST at the branch so you are likely going to be doing 90% of the config anyway.

HTH,

Art

Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

So much I agree, that I've rated

16 REPLIES
Bronze

Re: MGCP or H323/SIP gateway?

Hi,

Though H.323 provides more flexibility, you can achieve similar translations with MGCP GW registering with CUCM and configuring translation rules in CUCM on the basis of called number from PSTN.

Pls follow the following link which may help...

http://www.gossamer-threads.com/lists/cisco/nsp/97093

Alternatively, you can allow your IP phones register with CUCM, configure translations in your GW locally and register the GW as H.323 in CUCM. And you need to configure a dial peer pointing to CUCM for the translated called number range so that CUCM will provide signalling appropriately to establish the audio stream with respective IP phone at branch for the branch H.323 GW.

Regards...

-Ashok.

With best regards... Ashok ----------- Pls kindly rate if helpful or answered your question.
Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

You should always use H.323 or SIP.

MGCP has too many limitations, and is cumbersome to configure,

Silver

Re: MGCP or H323/SIP gateway?

I agree with Paolo,

Use H.323 or SIP.  MGCP can be flaky as well as being troublesome to set up.  You are likely going to be setting up SRST at the branch so you are likely going to be doing 90% of the config anyway.

HTH,

Art

Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

So much I agree, that I've rated

Silver

Re: MGCP or H323/SIP gateway?

Likewise!

Cheers!

New Member

Re: MGCP or H323/SIP gateway?

Thanks everybody for your time, that helped me a lot!

Cisco Employee

Re: MGCP or H323/SIP gateway?

All I would add is, yeah if u don't have any pressing need to do MGCP,

go with SIP (or H323)

And I would also recommend to do all digit manipulations/translations

on  the IOS side when using SIP/H323 keep things striaght specially

if u r going to use this GW as a SRST router as well.

New Member

Re: MGCP or H323/SIP gateway?

How about FXS ports? it is so much easier control dialing for devices attached to FXS ports when  F

XS ports register to CUCM via MGCP.

Silver

Re: MGCP or H323/SIP gateway?

This is just one man's opinion but I still don't think in the long or short run MGCP is an easier way to control any remote device.  Again in my opinion the biggest draw MGCP has is that you can centralize your dial plan on the CUCM, but it has so many issues against it as well.  If you become comfortable with the H.323 and SIP IOS commands you can very effectively control just about any port easily (and have a stable platform too).

I've worked with them all enough to know what works well, and what gives me headaches....

HTH,

Art

Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

FXS ports should be controlled via SCCP when connected to phones, or H.323 or SIP when connected to Fax or modems.

Even better, FXS porst on H.323 gateway are controlled by the router itself and CM doesn't need to anything.

New Member

Re: MGCP or H323/SIP gateway?

FXS port controlled by SCCP? you mean with adapters? I don't have adaptors, the FXS ports are for Fax and Polycom conference devices. Ideally I would want polycom/fax machines to all register to CUCM so I don't have to creat dail-peers on C2901 or on CUCM for corp internal dialing, the other reason is that branch office's outbound call will go out of SIP trunk to SIP provider, but SIP provider does not support Fax over SIP, so I'll need to create unique fax partitions to route outbound fax calls to PRI, I am not sure how I can achieve this on IOS. Can I use MGCP to control FXS ports but use SIP/H323 to control PRI/FXO ports?

Hall of Fame Super Gold

Re: MGCP or H323/SIP gateway?

Ad insicated above, you should NOT use MGCP fot FXS prot, or anything else.

New Member

Re: MGCP or H323/SIP gateway?

Yes, you can indeed use SCCP to control FXS ports that are in any IOS gateway.

In CUCM, build a new gateway (DEVICE > GATEWAY, add new) and choose this IOS type (2801, etc.  My 6.1.3 doesn't show the 29xx-series yet, but you should be OK using 28xx if not.  You don't need adapters, and VIC-FXS card or EVM module will be supported in gateways.  Choose SCCP and you can define the DNs in CUCM just as you would with MGCP.  Be sure to specify the MAC address of the 2x01 gateway in CUCM (last 10-digits).

In the IOS gateway, you'll need to enable SCCP and the STCAPP (SCCP Telephony Control Appliaction) like this or similiar:

stcapp ccm-group 1

!

ccm-manager config server {TFTP Server 1}{TFTP Server 2}

ccm-manager sccp local {Loopback}

!

sccp local {Loopback}

sccp ccm {SRST Reference} identifier 4 priority 4

sccp ccm {CallManager 3} identifier 3 priority 3 version xxxx

sccp ccm {CallManager 2} identifier 2 priority 2 version xxxx

sccp ccm {CallManager 1} identifier 1 priority 1 version xxxx

!

sccp ccm group 1

  bind interface {Loopback}

  associate ccm 1 priority 1

  associate ccm 2 priority 2

  associate ccm 3 priority 3

  associate ccm 4 priority 4

!

sccp

!

stcapp

!

ccm-manager sccp

!

Once SCCP and the STCAPP are running use "show sccp" and "show stcapp device summary" to check if it's registered to CUCM.  CUCM will also give you a "registered" status, and show you the IP address as well.  When the FXS ports are controlled by SCCP, there are 'psuedo-dial peers' created on the IOS gateway automatically...you'll see something like this that the STCAPP process puts in:

!
dial-peer voice 999200 pots
service stcapp
port 2/0/0
!
dial-peer voice 999201 pots
service stcapp
port 2/0/1

!

And certainly you can mix-and-match protocols for a given interface on the same gateway.  You can have FXS ports controlled by SCCP, and the PRIs controlled by H323/SIP/whatever.  But each interface must only have one protocol.

On all my gateways, I run SCCP to control FXS ports, H.323 to control T1s for PRI or FXO/DID ports if it's an analog site.(PSTN in and out).  I generally use H.323 for all my SRST-branch gateways PSTN services and station-side stuff for fax and analog phones stays at SCCP.  I only use MGCP at my headquarter's office where I need it for QSIG or other reasons that H.323 can't due to limitations.

I hope this helps.

Regards,

Mark

Silver

Re: MGCP or H323/SIP gateway?

Nice write up - well done! +5

New Member

Re: MGCP or H323/SIP gateway?

Hi  -

As the others have noted, stay away from MGCP for your branch offices.  It adds a layer of complexity and flakeyness that you don't need.  Just yesterday we had a major outage due to MGCP's inability to fail-over from one subscriber to another (still trying to find root cause).  H.323, in my opinion is the most stable of all for remote branch gateways.

While H323/SIP will allow you more control of digit manipulation at the gateway layer, I don't think you want or need it there.  Yes, translation profiles can indeed be powerful, but I think for maintenance purposes you can and should do them in CUCM.  You don't want to have to go into IOS each time you add a new phone at the site, for example.  Also, be mindful of the limitations with voice translation profiles.  I believe you can have 128 rules, but only 15 translations per rule.  That's bitten me before and forced me into NUM-EXPs.  You may be able to use them, or simply prefix all inbound DIDs that come from the PRI with a unique code such as "*123" before passing along to CUCM.  CUCM would then apply an appropriate translation pattern, unique to that site.

I hope this helps.

Regards,

Mark

New Member

Re: MGCP or H323/SIP gateway?

Hi Dear....

you cna use H.323 and it is best way for this setup and easily for configuration part.

and also for the troubleshooting part....

for this use you cna later easily handle the setup if faicng nay issue someitme...

Warm Regard's =========== Amit
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