ISDN connection issues with Korea

[machuky]

Hello to all,

I already had some issues regarding connections with Holland (knowing that I'm working in france ). It has been solved by our ISDN provider (traced the calls, and sorted the problem out ).
Now I'm trying to connect our systems, through a Tandberg Gateway with PRI ( 3 ISDN lines used, 384 Ks bonding ), and NO WAY !
Only one line is going up. I tried to call from our UK GW (via an IP connection to the GW first ). Different ISDN provider there, but no chance either...
Only one channel is building up, but 64 ks is not an option for proper VC... (56 ks modem with a webcam feeling if you know what I mean... )
The only thing that I have been told by the provider is : the lines are not synchronizing. So no bonding. And then a classic : must be Korean ISDN lines... That's a little bit of an easy response, innit ? Anyone had issues with Korea ? Entering calls are stucked to 64 Ks too... Hardware involved is full tandberg (990 MXP endpoints and GW ) . I even tried with Sony PCS-1P. Same thing. I tried with direct lines too ( France Telecom for these ), same result, again...
So basically, I'm in a bit of a dead end street.
Anyone has any idea to solve the problem ?

Thanx to all,

machuky

[mazzarak]

if I am reading it right, you have tried getting Korea to call you, and that gives the same result?

what happens when Korea make a more local call? For instance, get Korea to call their VC provider, or get them to call some test numbers in their region. Polycom have one - Test Number: +82-2-3288-2915.

See what happens when they make this call, and this might help you see if the problem is their end or your end.

[machuky]

Hey mazzarak, thank you for this quick response.

I'm gonna get in touch with the engineer in charge in Korea for him to give a try with this number. Looks like they are using VC with ISDN on a regular basis, so it should work locally. Plus they are using Polycom hardware, so testing this number should be usefull for sure.
Maybe it is a PBX issue, who knows ?
Anyway, I pass on the information, and ask for them to contact their provider as well.

Oh, and I was wondering, are there any fellow VC engineers from Korea on this board ?
If so, you can PM me, or drop a line in this thread.

Anyway, thanks for your assistance,

machuky

[Skylark]

The ISDN provider needs to have a "Multilink PPP" connection to the ISDN provider on the other end.

If there is no Multilink PPP the other can not assemble the packages correctly an you can only get on channal (64k).

You can probly read about this in a CCNA study guide or just look it up on the internet.

Using my current ISDN service provider I can call allmost any country in the world, but once in a while I find a country that I can not call and then I need to contact my ISDN provicer and he fixes the connection to that country.

[trapehzoid]

The ISDN provider needs to have a "Multilink PPP" connection to the ISDN provider on the other end.


Multilink PPP is a IP protocol and has nothing to do with getting 384kbs (or any other speed) on ISDN. BONDING is what takes care of putting the channels together, and that happens outside the ISDN lines.. at the IMUX level.

ISDN is very straight forward to debug between your gear and the switch when using tracing. You should get traces from the gear and send it to your vendor. They can tell you very easy if the problem is between you, and the switch. If not, its in the carrier to the far end.

Easiest thing to do is try to make a local call, as that eliminates most of the variables.

Since its a gateway, you might be able to call right back into itself (check the network status of the gateway to see if its actually calling out).

The line could be misprovisioned in how it handles data calls. ISDN traces are the best way to highlight that.