Different CSS on one H323 GW- Urgent

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Dec 4th, 2009
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With MGCP GW, each E1,T1 ciruict can have its own Inbound CSS due to the port it terminates on , with H323 as they are not configured in the same way do you create multiple instances of the same H323 GW`s in CUCM each with a differerent device name? If so does it matter what device name you configure for the GW- Unlike MGCP the device name match what is sent by the GW to CUCM


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iptuser55 Fri, 12/04/2009 - 09:48
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The reason I`m asking is this situation

Two E1,T1 with DID numbers 5551xxx and 2221xxx. In the CCM you have two customers with different site codes 222 and 555 if the telco sends you the last 4 digits 1xxx and the two different pipes as in MGCP each E1 terminates on different Ports can you can route differently due to CSS, Partitions- how do you do this with a H323 GW as above- Do you need to make use of Translations on the GW for each serial I/F? Another example  may be each Telco sends different digits i.e 5551xxx may send 4 digits but 2221xxxx may send 5 so you may need to change the 2221xxx bearer to make use of  only 4 digits in CCM

Jaime Valencia Fri, 12/04/2009 - 11:02
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You cannot configure the same GW twice, as you cannot configure in the ISR  h323-gateway voip bind srcaddr ip_address twice.

You will need to add another digit directly in the GW to differentiate the calls as they come into CUCM, or ask the telco if they can already send you more digits.

In CUCM you can then configure an inbound CSS for the GW that matches translation patterns: 51XXX and 21XXX, strip the 1st digit and via the TP CSS reach the right phone.



If this helps, please rate


You making this all sound very complicated. "Keep it simple"
I assume you have a H323 Gateway with two ISDN interfaces or a single interface with two ranges i.e 5551xxx may send 4 digits but 2221xxxx.
No matter what you have you have to know where to start...
You start with "debug isdn q931", "term mon" Example:
BR2-RTR# debug isdn q931
Feb 20 01:12:08.512: ISDN Se0/0/0:15 Q931: RX -> SETUP pd = 8 callref =
      Bearer Capability I = 0x8090A3
             Standard = CCITT
             Transfer Capability = Speech
             Transfer Mode = Circuit
             Transfer Rate = 64 kbit/s
     Channel ID I = 0xA8381
                    Exclusive, Channel 2
Calling Party Number I = 0x0081, ‘2123945002’
            Plan:Unknown, Type:Unknown
       Called Party Number I = 0x80, ‘32141891’
            Plan:Unknown, Type:Unknown

You can see the Called Party number will be the significant number, this is where the "significant digits" come in.
"significant digits" This is something that you can choose, starting from the last digit, depending on how long you want your extension range to be. You can even have multiple length extension range's (4 Digit or 5 Digit). In the example above we can go up to 9 Digit Extensions.
Most people Translate "Called Number" to fall into there "internal" extension range.
With H323 what allow the the call to enter and exit the Gateway from and to the ISDN interface is a "POTS" dial-peer: - this is your "Dial Plan"
dial-peer voice 100 pots
incoming called-number .
dial-peer voice 101 pots
destination-pattern 2123945...
port 0/3/0:23
forward-digits 10
dial-peer voice 102 pots
destination-pattern 6178631...
port 0/3/1:23
forward-digits 10
dial-peer voice 103 pots
destination-pattern 32143...
port 0/2/0:15
forward-digits 8
dial-peer voice 104 pots
destination-pattern 32143...
no digit-strip
port 0/2/0:15
prefix +34

Patterns is what is used in CallManager, all you need to understand here is you have the flexibility to create your own dial-plan. Use the "debug isdn q931" to see the numbers as you dial in or out...

CSS "Calling Search Spaces" is only there to restrict someone from dialing certain numbers.

Hope this help!! If so please rate?
Any questions please let me know?
Kind Regards,

iptuser55 Thu, 12/10/2009 - 01:59
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I don`t know if I`m confused but how are POTS dial-peer used for inbound H323 GW`s. I thought POTS were for outbound and VOIP`s were for inbound for H323  but for MGCP POTS are used for both ways -Am I missing something?  I understand that I can use translations to to delete , add digits based upon the inbound CSS of the GW which then points to the TP`s rather then make use of the sig. digits if need be 


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