PRI between 908e and Cisco 3900

[gregh]

Having trouble bringing up T1 PRIs between Adtran 908e and Cisco 3900.

Problem 1 is that the Cisco 3900 has a 4 port VWIC3 card and only a single T1 will come up at a time.

Problem 2 is that even with the single T1 operational the PRI won't come up.

Here is the config on the Cisco 3900 T1s and D-Channel:

controller T1 0/0/0

cablelength long 0db

pri-group timeslots 1-24 service mgcp

interface Serial0/0/0:23

no ip address

encapsulation hdlc

isdn switch-type primary-ni

isdn incoming-voice voice

isdn bind-l3 ccm-manager

isdn outgoing display-ie

no cdp enable

!

And the Adtran 908e T1 and PRI:

interface t1 0/3

  description Customer T1 handoff for PRI 2

  tdm-group 3 timeslots 1-24 speed 64

interface pri 2

  description LS529963-2

  isdn switch-type 5ess

  isdn name-delivery setup

  calling-party override if-no-CID

  calling-party number 6027595380

  connect t1 0/3 tdm-group 3

  digits-transferred 4

  role network b-channel-restarts disable

Any ideas greatly appreciated, thanks.

[Anonymous]

Greg,

Thanks for posting!  We may need to see the rest of the PRI configuration, including the isdn-group and the associated voice trunk.  However, I'm concerned that there appears to be an ISDN switchtype mismatch.  The Cisco looks to be set for National ISDN, while the Adtran unit is set for 5ESS.  I would start by changing the following on the Adtran unit.

interface pri 1

isdn switch-type ni2

Once you have that changed, I would verify the T-1 is up and error-free by using "show interface t1 0/3".  Then run "debug isdn L2-formatted" to see if any negotiations are taking place.  Feel free to respond with that debug output so we all can view it.

Thanks!

David

[gregh]

Hi David,

Thank you for the reply.

We've been trying different isdn switch-types but we have been matching them between the Cisco 3900 and the 908. It doesn't appear that the C3900 has an ni2 option  though. We've currently settled on ni2 on the 908 as that is our standard config.

We have two PRIs and here is the output from the debug isdn l2-formatted command:

• 13:51:25.283 ISDN.L2_FMT PRI  1  ==============================================
• 13:51:25.283 ISDN.L2_FMT PRI  1  Sent  Sapi:00 C/R:C Tei:00 Ctl:SABME   P:1
• 13:51:26.283 ISDN.L2_FMT PRI  1  ==============================================
• 13:51:26.283 ISDN.L2_FMT PRI  1  Sent  Sapi:00 C/R:C Tei:00 Ctl:SABME   P:1
• 13:51:26.284 ISDN.L2_FMT PRI  2  ==============================================
• 13:51:26.284 ISDN.L2_FMT PRI  2  Sent  Sapi:00 C/R:C Tei:00 Ctl:SABME   P:1
• 13:51:27.283 ISDN.L2_FMT PRI  2  ==============================================
• 13:51:27.283 ISDN.L2_FMT PRI  2  Sent  Sapi:00 C/R:C Tei:00 Ctl:SABME   P:1

My reading of the output is that the 908 is attempting to communicate with the C3900 but not receiving a reply.

And here is a T1 (t1 0/4 is identica)l:

• interface t1 0/3
•   description Customer T1 handoff for PRI 2
•   tdm-group 3 timeslots 1-24 speed 64
•   no shutdown
• t1 0/3 is UP
•   Description: Customer T1 handoff for PRI 2
•   Receiver has no alarms
•   T1 coding is B8ZS, framing is ESF
•   FDL type is ANSI
•   Line build-out is 0dB
•   No remote loopbacks, No network loopbacks
•   Acceptance of remote loopback requests enabled
•   Tx Alarm Enable: rai
•   Last clearing of "show interface" counters 1d 23:01:05
•     loss of frame  : 1, last occurred 1d 22:57:29
•     loss of signal : 1, last occurred 1d 22:57:28
•     AIS alarm      : 0
•     Remote alarm   : 1, last occurred 1d 23:01:05
•   DS0 Status: 123456789012345678901234
•               XXXXXXXXXXXXXXXXXXXXXXXX
•   Status Legend: '-' = DS0 is not allocated
•                  'X' = DS0 is allocated (nailed)
•   Signaling Bit Status: 123456789012345678901234
•                    RxA: 001110110000100000110011
•                    RxB: 001000011001100000111001
•                    TxA: 000000000011001100000000
•                    TxB: 100110000011100110011000
•                         123456789012345678901234
•   Line Status: -- No Alarms --
•   5 minute input rate 0 bits/sec, 0 packets/sec
•   5 minute output rate 24 bits/sec, 1 packets/sec
•   Current Performance Statistics:
•     0 Errored Seconds, 0 Bursty Errored Seconds
•     0 Severely Errored Seconds, 0 Severely Errored Frame Seconds
•     0 Unavailable Seconds, 0 Path Code Violations
•     0 Line Code Violations, 0 Controlled Slip Seconds
•     0 Line Errored Seconds, 0 Degraded Minutes
•   TDM group 3, line protocol is not set
•     Encapsulation is not set

And here is the ISDN:

• isdn-group 1
•   min-channels 1
•   max-channels 23
•   connect pri 1
• !
• isdn-group 2
•   min-channels 1
•   max-channels 23
•   connect pri 2

I don't have direct access to the C3900 so can't manipulate it directly.

Thanks for looking at this. I'm stumped.

[gregh]

Forgot the Voice Trunks (SIP upstream to the Network with PRI handoff to the C3900):

• voice trunk T02 type isdn
•   resource-selection linear ascending
•   caller-id-override number-inbound 1234567890 if-no-cpn
•   connect isdn-group 1
•   no early-cut-through
•   modem-passthrough
•   t38
•   rtp delay-mode adaptive
•   codec-group DYNAMIC
•  
•   voice trunk T03 type isdn
•   resource-selection linear ascending
•   caller-id-override number-inbound 1234567890 if-no-cpn
•   connect isdn-group 2
•   early-cut-through
•   modem-passthrough
•   t38
•   rtp delay-mode adaptive
•   codec-group DYNAMIC

[Anonymous]

gregh,

       Below is an example of all the pieces needed for a PRI connection from the Adtran side, I did not see the timing statement :

interface t1 0/4

  description PRI

  tdm-group 1 timeslots 1-24 speed 64

  no shutdown

!

!

interface pri 1

  connect t1 0/4 tdm-group 1

  digits-transferred 7

  no shutdown

!

!

isdn-group 1

  connect pri 1

!

!

timing-source t1 0/4

!

[gregh]

Hi jwable, thank you for the input. Lots of output up there, easy to miss some of the statements.

Here are the connect statements associated with the isdn-groups:

• isdn-group 1
•   min-channels 1
•   max-channels 23
•   connect pri 1
• !
• isdn-group 2
•   min-channels 1
•   max-channels 23
•   connect pri 2

And here is the connect statment for one of the PRsI:

interface pri 2

connect t1 0/3 tdm-group 3

And the debug statements also show that the 908 is trying to communicate with the Cisco router but not receiving a reply. I suspect the vendor working on the router is not configured properly.

[Anonymous]

gregh,

      I eddited the reply I think you saw it before I corrected it.  The one thing I didn't see was the the timing source statement.  Another thing you might try if you haven't already is try swapping the cable type between straight through and cross over sometime just to cover your bases.  I have just started looking at using Cisco for voice so I can't provide any input on it's configuration but I am not 100% sure that the service type of MGCP is correct for a PRI hand off.

John Wable

[Anonymous]

gregh,

    I believe the following would be a more acurate config for the T1 on the Cisco like I said just started looking at Cisco so I could be off a little but the below example makes more since then what the above snippet contains:

controller t1 0

framing esf

linecode b8zs

isdn switchtype primary-4ess

John Wable

[gregh]

jwable,

The T1s are functional at this point so the cables are good. As for the timing, I'm assuming as the 908 is acting as the network the 908 would provide the timing. Not sure if that is correct but that's how we are setup and the T1s are synched up just fine with no slips/errors.

As to the service type MGCP, I had to do some research to figure out what it means. Appears to be a mechanism to hand off the layer 3 functionality of the ISDN D-channel to a Call Manager. The customer is using the Cisco router as a gateway and the Call Manager is handling the layer 3 stuff.

We still don't have D-channel layer 2 between the Cisco and the 908 but as I posted previously, the 908 debug seems to indicate that the 908 is attempting to communicate and the Cisco router is not responding.

Fun stuff.

[Anonymous]

gregh,

      Just another thought here on a different possible solution.  What if you where to use the Adtran 908e with SBC and then configure it for SIP to SIP instead of SIP to PRI.  That way you would still be able to manage your demarc point but at the same time just run everything SIP.  Obviously there is additional expense but it maybe worth the expense if you don't have keep going back and forth between the Cisco vendor and multiple config changes on your end.

John Wable

[gregh]

Update:

Vendor removed the following command from the Cisco router,

• pri-group timeslots 1-24 service mgcp

And replaced it with:

• pri-group timeslots 1-24

Not sure what this changes, maybe the service type is H323?

Anyway, PRI layer 2 came right up so it appears there is some sort of interoperability issues between the 908 and the Cisco router with "service mgcp".

Let the finger-pointing begin.

[gregh]

So the new big question is does the 908e, running AOS Version A5.02.00.E, support MGCP via PRI D-Channel to a Cisco. Some quick google searchs indicate that the IP Business Software on the Adtran.

[gregh]

Correction:

Some quick google searchs indicate that the IP Business Software is required on the Adtran.

[Anonymous]

gregh,

    First the Adtran hands off good old TDM PRI therefore the other end should be configured as a standard PRI configuration.  I had posted the Cisco recommended examples above for a standard PRI configuration.  In most of the examples I have seen for MGCP service configurations appear to be for using the Cisco to handle a channelized/digital T1 instead of standard PRI trunks.  So I feel the MGCP service was in correct to start with.  But as I stated I have just started looking into CIsco voice so hopefully someone with a little more Cisco experience can confirm or deny my explainations.

John Wable

[Anonymous]

Gregh,

    Well I finally found a good example and I guess I am wrong with the above statements.  It appears that the purpose of MGCP service is so that the call manager can control the PRI directly.  I found this example and step through: How to Configure MGCP with Digital PRI and Cisco CallManager - Cisco Systems

So the question is did they have all the Cisco parts configured correctly because there should be no reason it should not work that I can see.  The article does mention a couple of items that might need adjustments based on the debug output and timing sources.

John Wable

[gregh]

John,

More data has come to light regarding the design. So, it appears that this is a "PRI Backhaul" solution using a Cisco Call Manager.

The "pri-group timeslots 1-24 service mgcp" cisco command gives control of Q.931 (L3) ISDN D-channel messages to the Call Manager. The Q.931 messages are passed THRU the router BUT, the Q.921 messages terminate on the router.

From the link below,

“…the gateway does not bring up the D-channel unless it can communicate with Cisco CallManager to backhaul the Q.931 messages contained in the D-channel.”

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801da84e.shtml

I'm awaiting verification that the Cisco router is communicating with the Call Manager. If that is not the problem it would appear that we have compatibility issues between the Adtran 908 and the Cisco router.

[gregh]

Looks like we're reading the same articles. Thanks for all the input. This has been an educational exercise to say the least.

[gregh · Accepted solution]

PRIs are finally operational. This was NOT a compatibility issue between the Cisco router and the Adtran 908.

For all  you Cisco Voice guys out there, the Call Manager has to be in communication with the MGCP Gateway, the Cisco router in this case, for the PRI D-Channel to come up.

Guess what, the Call Manager was no pingable the whole time we had been troubleshooting. Would have thought the voice vendor would have known this.

Lesson learned, case closed.