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RE: (ASCEND) T1 provisoning hints
Hi Greg, thanks for the nice words.
Let me try to illustrate line-side versus trunk-side in the context of
what we're talking about here.
As you know most switches, and certainly your DMS-10, can have (at
least) 2 different ways to connect to subscriber equipment. When
someone says that you are connected to the line-side of the switch, they
mean that you are connecting to individual, separate, analog ports that
have exactly one CO line. For all intents and purposes, the line-side
delivers classic electrical Tip and Ring, and you hook that up right to
copper paths.
RBOC's, when they buy switches have to satisfy the bazillion pairs of
copper that ingress to the CO, and they do that by buying line-side
packs for the switch.
Trunk-side is classically the digital side, and I believe got it's name
from that fact that "trunks of lines" were delivered in a digital format
from those packs. So the trunk-side of the switch would normally
aggregate 24 individual phone lines onto a T1 for delivery to customer
PBX's and such that know how to decode that format properly. This side
of the switch is truly digital, and has no analog component associated
with it. This is the "side" of the switch that you *want* your T1's
delivered from, and it is the "side" of the switch that all PRI are
delivered from.
Here's the rub: Joe's ISP Inc. calls the RBOC, Bell Atlantic for
instance, and orders up a "channelized T1" from the Telco. They tell
Joe that this will be delivered on a T1 digitally to Joe's location. It
will have 24 voice channels, and they will all hunt to each other. It
will have a format and framing of B8ZS, ESF. Joe checks the Ascend Web
page, and all looks good so far.
Then, and very often, and without your knowledge the RBOC will take 24
line-side CO lines (remember, they're analog at this point!) and run
them into a D4 (or some other) channel bank that takes the 24 analog
lines, and multiplexes them onto a digital T1 to send to you. The
problem is that they added an A/D conversion in the path that you are
unaware of. This kills the whole party. You *must* be very specific
and ask for engineering verification from the RBOC, that there is
absolutely no A/D in the T1 path at all. (BTW, this is a classic reason
for never seeing 28.8K connections, but seeing loads of 26.4's)
I used Bell Atlantic as an example because of my experience with them.
FYI, Bell Atlantic *always* provisions line-side T1's. They do not have
a tariff for trunk side. If you want trunk-side from BA, you first must
be enlightened enough to ask, then they must issue for internal approval
what is known as an HSA, or House Special Assembly. BA's charges for
trunk-side HSA T1's is close to $80 buck a line, with a $2000 install.
All RBOC's have the equivalent of an HSA - it's their way of getting
around tariff's for special circumstances.
Nynex, on the other hand has a product they call FlexPath, which IS
provisioned trunk-side.
Clear as mud? :-)
Best regards,
David Van Allen - You Tools Corporation / FASTNET(tm)
dave@fast.net (610) 289-1100 http://www.fast.net
FASTNET - PA/NJ/DE Internet Solutions
>-----Original Message-----
>From: Greg Hale [SMTP:greghale@logantele.com]
>Sent: Saturday, June 28, 1997 12:54 AM
>To: Dave Van Allen
>Subject: Re: (ASCEND) T1 provisoning hints
>
>Thanks alot Dave.
>
> We just put in two 4048's and I think this will help alot when I get back
>to the office on Monday. You seem to know more about line provisioning
>than the Ascend tech's. We've been having a great deal of trouble. No
>56flex connections at all. I work for a small telephone cooperative in a
>rural community in Kentucky. Many of our customers dial in from Bellsouth
>however.
>
>Unfortunately we cannot use PRI because Nortel does not offer it in the
>DMS-10 yet. We only serve about 6300 access lines and cannot justify the
>move to a DMS-100. They keep pushing back the date to add it to the
>DMS-10. Last word was late this year. So I'm stuck with using the
>channelized T1. Two different tech's from Ascend dialed in from California
>and got 46000 and 48000 but we can't even get a connect. The modems try to
>connect at 56flex but disconnect. The only way they can connect are by
>forcing them to v.34.
>
>I'm not sure we even understand what a line side T1 is and we're getting
>very little help from Nortel. I spent 30 minutes, wasting my time, arguing
>with my C.O. supervisor and a guy from Nortel this afternoon. The guy from
>Nortel knew so little about the 56flex technology that he argued that the
>only way people would connect higher is if they had a switched 56 line and
>tried to sell us line packs to try to sign our customers up with switched
>56 to their homes. I hope this gives you some kind of idea of what I'm up
>against. I'm an outside plant engineer who's had the Internet dropped in
>my lap because of my education in Computer Science and Engineering. We
>have limited resources since we're such a small company.
>
>I'd like to understand what a line side T1 is. The only thing I could
>think of is like I could get a T1 to a person or business by running it by
>HDSL through one of our DLC's. I'm not sure if this is correct or not but
>would love to know. It seems like I have the T1's trunk side but from your
>description below I'm not sure. I don't know what a D4 converter is. We
>intercept our dial in number and put it on one of four T1's. The Max's are
>in the same C.O. as the switch. Because of this and because the others
>were able to get 56flex connections from CA makes me believe that they are
>coming in too hot for local customers.
>
>It looks like I've got one thing wrong for sure. We've got the line to
>trunk pad set at 1db and from what you are saying this should be zero.
>You're right about setting them up like voice. My C.O. guy keeps trying to
>compare these trunks to EAS trunks which he sets at a -3 and toll trunks
>which are set at -6.
>
>Well as you can tell by now I've got a real mess and don't know much about
>any of this trunk provisioning stuff but I know I've got to get it fixed
>because noone else is taking the lead. Any help you can give would be
>greatly appreciated, and then maybe I could get some sleep. I took a look
>at your site and it looks like you've got a great service. x2 and 56flex,
>T3's, etc. It's nice to know that some I.S.P.'s are trying to do things
>the right way. If I was on the east coast I'd sign up.
>
>Thanks in advance,
>Greg Hale
>----------
>> From: Dave Van Allen <dave@fast.net>
>> To: 'Nelson Lee' <lnelson@e-zone.e-z.net>; 'Ascend User Group'
><ascend-users@bungi.com>
>> Subject: (ASCEND) T1 provisoning hints
>> Date: Friday, June 27, 1997 4:32 PM
>>
>> Nelson, et al.:
>>
>> Here's some tips and comments that might help with both 56K and regular
>> line provisioning for PRI and T1 circuits to RAS equipment such as the
>> Max family of servers.
>>
>> One of the questions below dealt with a mysterious quality of service
>> difference. Here may be the reason:
>>
>> First, the way that the RBOC's deliver the customer's phone calls or
>> modem calls to the CO (Central office) from the various rate centers may
>> be (and often are) very different. For instance, in the neighborhoods
>> where you serve customers, some of those areas may be serviced directly
>> to the CO on dry copper, with no bridge taps, loading coils or repeaters
>> in the line. This is good for modems, and especially K56Flex or even x2;
>> expect happy customers.
>>
>> Or, the customer could be on dry copper but *with* bridge taps, loading
>> coils or analog repeaters in the line. This normally happens because of
>> a distance greater than apx. 12000 feet from the CO or *shorter than*
>> 4000 feet. This starts to make things marginal for the better data
>> connections, but still may be usable for mid level 40K or so K56
>> connections, and mid 20K V.34's. Expect customers questioning why they
>> can't get good connect rates.
>>
>> Next, the neighborhood could be served by a SLC - Subscriber Loop
>> Concentrator. This ugly-data-crushing device takes the copper from the
>> home, and does at least one and often more A/D then D/A conversions, as
>> it passes the signal over digital facilities to the CO. There at the CO
>> the signal is "de-muxed" and often attached back onto the MDF
>> (Multipoint Distribution Frame) where it heads into the Line side of the
>> CO's switch. Some popular switch type examples are Northern Telecom DMS
>> series, AT&T/Lucent 5ESS, AT&T 1A. SLC's are often used where the RBOC
>> needs a high concentration of lines, or where the RBOC needs to feed a
>> residential or industrial area that is very far from the CO. They are
>> also being deployed due to cost efficiencies.
>>
>> If you are fed from a SLC, expect nothing but trouble, and zero recourse
>> from the RBOC. Your customers will be unhappy, and there is nothing you
>> can do.
>>
>> Also, it is not uncommon for half the neighborhood to be served by one
>> method above, and the other part from another. I had an instance where
>> two people lived right next to each other - one got great rates, his
>> friend didn't. Investigation showed two different paths into the CO from
>> the two homes.
>>
>> Problem tracking:
>>
>> It is very rare that the customer has the classic excuse of "bad phone
>> lines" at their home. Don't even go there first if the home is less
>> than 5 or 7 years old. It is just very unlikely and a better bet would
>> be one of the above. I have found that the phone company will at times
>> be very helpful in telling the customer how his/her circuit is actually
>> built and in some cases, can ever change a few things to the situation
>> better. You'll get more Bees with Honey with respect to this item!
>>
>> The connection-results in the K56Flex modems at&v1 will show a bunch
>> of info. Two important fields are Line Quality and I think the other is
>> marked Receive Level. A receive level of 019 for instance, refers to an
>> incoming to-the-home modem signal that is -19dbm. -19dbm is very
>> marginal. Better numbers are -17dbm through -14 dbm, and more than
>> -20dbm will most likely never work. The Line quality indicator is a
>> factor derived from many sources, and is too complex for this
>> discussion. A Good Line quality is anywhere from 1-75 or so, anything
>> higher will begin to be detrimental to the connect rates.
>>
>> Finally, ISP's that run their Maxen from T1 circuits (not PRI) need to
>> remember and be cognizant of the following:
>>
>> 1) The T1 *must* be "trunk-side provisioned, never Line-Side. Line side
>> will go through a D4 converter prior to being delivered. This is not
>> just bad - it's a show stopper. I have counseled many an ISP who was
>> told from the RBOC that "ya it's digital all the way!". Well it is
>> almost, but almost only counts in Horse-shoes and atomic bombs, me
>> thinks.
>>
>> 2) The receive level from the inbound ISP T1's must be within spec for
>> the equipment being used. The LBO (Line Build Out) parameter on the
>> Maxen's adjust the padding to the CSU to present the proper level as
>> derived from the incoming T1 circuit. The RBOC should (read probably
>> won't) be able to advise you on the proper setting for your specific
>> installation. It is an adjustment that you can play with on your own if
>> you are having troubles. The default of 0 is often correct, and that's
>> how Ascend sends the units out. It is important to remember that too
>> much signal is just as bad as too little.
>>
>> 3) The CO switch group that you are trunk-side provisioned from, must
>> *not* place voice-shaping pad groups on your circuits. For the NT DMS
>> series delivering trunk-side data service on a B8ZS ESF T1 to your Max,
>> the trunk group should have the NILPADGRP applied to the outbound side.
>> The Lucent switch has a similar setting called I believe NOOP. Both of
>> these mean essentially, NO PADDING or FREQUENCY RESPONSE SHAPING
>> APPLIED. It has been my experience that most RBOC's and CLEC's do not
>> understand this, and will just build things up as if they were to be
>> used for voice. You will have to really dig to get someone to tell you
>> this information, but you *can* get it...and it could easily be your
>> whole problem!
>>
>> A note on PRI's:
>>
>> PRI's are naturally trunk-side provisioned, and have less complications
>> based on install practices. They also have slightly better bandwidth
>> per channel characteristics because all signaling is done out of band on
>> the D channel. Use them if you can.
>>
>> Hope this helps a bit, if not - I needed to practice typing anyway. :-)
>>
>>
>> Best regards,
>>
>> David Van Allen - You Tools Corporation / FASTNET(tm)
>> dave@fast.net (610) 289-1100 http://www.fast.net
>> FASTNET - PA/NJ/DE Internet Solutions
>>
>>
>> >-----Original Message-----
>> >From: Nelson Lee [SMTP:lnelson@e-zone.e-z.net]
>> >Sent: Friday, June 27, 1997 1:40 PM
>> >To: Ascend User Group
>> >Subject: (ASCEND) 56k/telco
>> >
>> >
>> >We got our Max4048 about three weeks ago to go along with our fiber PRI.
>
>> >As I test from the various neighbourhoods that our ISP serves, I find
>that
>> >some people have no trouble getting connections as high as 50k to our
>Max.
>> >However, in other areas, the exact same equipment will give up on 56k
>and
>> >fall back to v.34. The odd part is that the v.34 connections are
>usually
>> >fast (26.4 - 31.2), which is just what I see when I force a v.34
>> >connection in those areas that can get 56k. When I check signal
>strength
>> >and line quality, I see similar results in both the areas that can get
>56k
>> >and the areas that can't.
>> >
>> >So, the question is: Why can't some of these areas get 56k? Is this a
>> >telco problem? Could they be throwing an extra D/A and A/D in the loop
>> >somewhere? Is there any way to test for this?
>> >
>> >(BTW, when I refer to 56k, I mean 56k as opposed to v.34 -- 32000,
>34000...).
>> >
>> >------------------------------------------------------
>> >| Lee Nelson |
>> >| lnelson@e-z.net |
>> >| http://www.e-z.net/~lnelson |
>> >|----------------------------------------------------|
>> >| System Administrator, E-Z.Net Inc. |
>> >| (360)260-1122 |
>> >| 209 NE 120th Ave. Suite B |
>> >| Vancouver, WA 98684 |
>> >------------------------------------------------------
>> >
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