Ascend Archive
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Re: (ASCEND) Problems with T1<->PRI and Max4004
I am using PRI<->T1 conversion to peel off PRI channels for our
phone system. My T1 is ESF/B8ZS (as is my PRI). I have not seen
the delay you speak of. I don't have modem banks hanging off
my pbx but have tested modem to modem through the
Max<->Channel Bank<->PBX setup that I have. It worked fine
without the delays you see (I was using some off-brand modem, not
USR). At the time of the tests I was running 5.0ap16.
I suspect the problem may have something to do with the ESF/B8ZS
to D4/AMI conversion. Your phone calls (to/from the pbx) don't experience
delay though do they?
As far as the channels hanging in a "c" state I did see that
in the past when I was trying to get the parameters between the
Max, channel bank and PBX. I'm sorry but I don't remember
the exact parameters involved. Once I got it all set up correctly
(and that was difficult given the number of variables) I have
not had a problem with this. I just installed 5.0ap44 so I will
keep an eye out for the channels hanging, but none so far in the
4 or 5 hours since upgrading.
Is there anyway to set up the T1 for ESF/B8ZS or doesn't your
PBX card support it?
Tom
At 11:19 AM 3/12/98 -0500, Wes Morgan wrote:
>
>[ This message is long - you have been warned. ]
>[ Ticket opened with Ascend, but I've been wai- ]
>[ ting way too long for a callback. ]
>
>
>Equipment:
> Max 4004 w/DM-12,BRI,Host/Dual cards, T1<->PRI installed (5.0Ap42)
> Meridian PBX (connected to Max via T1, D4/AMI)
> USR Total Control modem bank connected via PBX
> PRI circuit inbound from telco (ISDN signal, AT&T switch ESF/B8ZS)
>
>Symptoms:
>
>1) Calls to the USR Total Control modems (through the Ascend to the PBX)
> experience a pattern of delays. This delay occurs if the T1<->PRI link
> is traversed, either inbound, outbound or both. Pattern includes two
> delays of up to 14-16 seconds, as tested with ping(1); no packets are
> lost, but seem to be buffered.
>
>2) Pattern is not present when calling DM-12 modems via the PRI. Pattern
> is not present when dialing USR Total Control via DID trunks (bypassing
> the Ascend). Pattern is not present when dialing USR via PBX (i.e.
> dialing local 3-digit extension to reach modem bank)
>
>3) We have two Pipelines making ISDN calls to the Max via the telco PRI.
> They do not show this behavior.
>
>Attempted Resolutions:
>
>1) Installed new Max 4004 per RMA.
>2) Modified characteristics of Win95 DUN. (1.2b)
>3) Upgraded to 5.0Ap42 (from 5.0Ap24)
>
>Other problems:
>
>1) Channels on the T1 between the Max 4004 and the PBX occasionally hang
> in "calling" state. (i.e. status display is 'c') The only way to clear
> these is to remove the T1 from the Max for a few seconds, and then re-
> connect it. (These build up over time; I went 6 days without one, but
> have seen 6 channels hang in the last 24 hours.)
>
>2) DM-12 modems (v.34) cannot maintain a connection in the absence of data.
> If I *immediately* start some sort of traffic generation (i.e. FTP ses-
> sion or 1000-ping barrage), the connection will stay up until the data
> ends; once the data stops, the connection is dropped within 10-30 seconds.
> (I have disabled all idle timers)
>
>
>Supposition on delays:
>
>The T1 connection is D4/AMI, which the telco informs me is 56K data and
>8K signaling. This is being converted to a 64K PRI data stream; the re-
>verse is taking place on inbound data. Is it possible that this signal-
>ling change is dropping bits? Is this translation particularly slow, cau-
>sing (perhaps) these delays every 30 seconds or so? The fact that these
>delays do not occur when calling the DM-12 modems would seem to indicate
>that the telco PRI is basically healthy.
>
>Supposition on T1 channels "hanging":
>
>I have no clue.
>
>Supposition on DM-12 modem performance:
>
>I'm at a loss on this one. I've disabled every timeout I can find, and
>they just won't hold a connection. I read in the 6.0 Release Notes that
>Ascend "has problems with IPX," but I see the same behavior on IP-only
>PPP calls. I've upgraded to the latest Win95 DUN (1.2b), also per the
>6.0 Release Notes.
>
>Comments/suggestions welcome. If you'll send your comments to me, I'll
>summarize them back to the list.
>
>--Wes
>
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