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Virtual PRI

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aarenot

Vendor
Aug 30, 2003
2,383
US
TELCO has 2 T1's going into the Crisco unit to provide 3Meg internet, with a virtual PRI coming off the cisco unit for 11 channels PRI(dynamic allocation). They do not seem to be able to even tell me the switch type emulation, or anything at all. No matter which switch type I set to I could not see the D channel. Anyone done a virtual PRI like this previously? TDS

 
You mean a D channels from the cisco ?
Then it is a no go
Mostly it is only b or only d channels
I have worked with sip from provider to a cisco wich converted it to isdn30 (E1) and i could not get d channels, only b channels


ACA - Implement IP Office
ACS - Implement IP Office
ACA - Voice Services Management
______________
Women and cats can do as they please and men and dogs should relax and get used to the idea!
 
I did one of these last week, it was just a regular NI2 ESF B8ZS circuit as far as the IPO was concerned.
 
Sorry, after I posted I remembered that from the Cisco you need a T1 crossover cable - cross 1-4 and 2-5, or blue-orange/white and blue/white to orange.
 
The TELCO guys, all 4 of them which were on site did not know anything about this virtual PRI at all, and did not even believe that they provided, or sold this product. The on site 4 guys just boot strapped the cisco unit, and remote guys downloaded the IOS, and even these guys would only say it was not any of the switch type emulations of the IPO options, but that it should work with any of them. They also went back, and forth between telling me I had to set up the 11 channel PRI as a 23, and they would just only allow 11 concurrent channels to be used, and that it had to be set up as an 11 channel PRI depending on which guy was talking at the time. I tried a crossover cable which did nothing, and the entire time I could not detect, or see the D channel at all.
The last guy that showed up, and the only one who would admit that the only way to see any data on the PRI itself was to log into the cisco unit could not log into it because his username, password were locked out for some reason, and his help desk was not open to get him back in.

I told them we can try this again when they are ready to drop the ISP down to 1.5M, and give me a live circuit to test prior to taking down the POTS lines. They were supposed to have this up for testing prior to taking down the ADIT600 providing dial tone, but instead they converted the existing circuit not bringing up the virtual PRI until after 8PM that evening. 4 hrs i waited for the non-functional PRI, at which point they walked without ever telling me their switch type even.

 
Got it working this morning. Tried an identical T1 crossover cable to the one the TELCO provided on Saturday, and it worked. TELCO guy said he thought that was it, but I still had the one the TELCO provided on Saturday, and it was exactly the same as the one that worked on Monday, so you know it was the configuration, or hardware on their end like the manager had admitted on Saturday.

I did not change anything on the IPO from my original saved, and reloaded CFG from Friday. I also told the TELCO that I did not have the cable in hand that we tried on Saturday to see if he would claim it was the cable that we used that would not work with their reversed PRI which they provided. It was true that I did not have them in hand, but I did have them in truck, and just wanted to see if they would try to say it was the cable not their configs. I checked the cable in the truck, it was good, and it tested out perfect, and identical to the one they provided Monday morning.

I also wonder on others opinions on this reversed PRI. I ordered a PRI, and as far as I know that is standard in the pin out as to where they pin out. This reversal is not standard for PRI that I am aware of, and wondered if I am missing something here, and if there is a name for this reversed PRI pin out?



 
A data T1 cross-over is indeed different than a PRI cross-over cable. PRI swap pins 1 and 2 with 4 and 5. Data cross-over switches pins 3 and 6 with 4 and 5.
 
I did forget that (T1 crossover difference thing)at first, and went to get a data crossover adapter on Saturday, but before I got the adapter it came to me. So we did use a T1 crossover not a data crossover on Saturday, and Monday even though the TELCO demanded a crossover was not needed on Friday, and Saturday before changing their tune on Monday morning.

I really think the telco needs to be able to do better than delivering a PRI card 4 hours late, requiring a crossover but demanding it does not, requiring the PBX be configured for 23 channels when it is only 11, and not even being able to tell me a switch emulation for the PRI. If I had listened to them it would still be set up for 23 channels not 11, DMS 100 not NI2, not on a crossover cable, and had two more DID's on it that are supposed to be analog trunks still.

 
I have done a lot of PRI's with Cisco IADS and they all need a T1 crossover. Most of the telcos here will provide a cable with a RJ48X on the end of it to loop back to the cisco when we are unplugged. I have seen a lot of these virtual PRI's here. THey bring in 1 or 2 T1's to the IAD and send out a PRI and data. They use it like a flex-path. If the voice is not used it is Data. I think most of them are really SIP to the IAD. We have trouble with Faxes all the time over these.

Kevin Wing
ACA- Implement IP Office
Carousel Industries
 
A data T1 cross-over is indeed different than a PRI cross-over cable. PRI swap pins 1 and 2 with 4 and 5. Data cross-over switches pins 3 and 6 with 4 and 5.

A data cross over is pins 1,2 and 3,6
You are talking about a BRI crossover :)


ACA - Implement IP Office
ACS - Implement IP Office
ACA - Voice Services Management
______________
Women and cats can do as they please and men and dogs should relax and get used to the idea!
 
The cisco units in this area are quite recent additions to the mix. Adtran, and the adit600 are quite popular here, but that is changing. With the X-Data, or dynamic type circuits being offered I am advising my clients to change the TELCO thinking from their past norm of provision.

The TELCO here is frequently an ILEC which wants to rent a pair to bring in a T1, and channel bank out analog trunks using dedicated bandwidth on the T1 for this. I am leaning them toward dynamic provision, and breaking the PBX voice out to a partial PRI like in this case which uses dynamic allocation to return the bandwidth to data when voice channels are not in use. I also get involved early, so that the analog device trunks are not even considered as an option to be ported to the PRI for the fax, and alarm circuits. The ILEC can provide those however they want, but not on my PRI, and I tell my customer that up front.

Some ILECs tell me they can not provide a PRI, and analog trunks off the cisco IAD at the same time, but some tell me it is not a problem. What is your experience with the IADS being able to provide both types of trunks off one unit?

 
Providing analog and digital at the same time shouldn't be a problem with a IAD2400 as long as they have enough slots. It should just be a matter of configuration.
 
I found out today someting about them providing analog trunks along side the PRI, guess what. They were wrong about their original statement that the equipment could not provide both, lol. Surprise, surprise.

 
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