I have been told that an ISDN line is just a quicker phone line for modems, etc. but that ISDN lines are NOT T1s. My boss is asking me to order three ISDN lines for some videoconferencing equipment and he's requesting the smartjack be run from a to b, etc. My question is, isn't a smartjack for T1 use? and what IS a "smartjack"? i feel ridiculous calling Verizon because I truly have no idea what I'm saying to them. i appreciate your assistance. Thank you.
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ISDN vs. T1
- Thread starter coniglio
- Start date
Are you ordering these isdn lines to connect directly to your video equipment or are you ordering them for your pbx?
If you are ordering three isdn BRIs, you will need to know what type of video equipment you are connecting to.
ISDN bri lines are "digital" phone lines. Verizon will deliver each line on a 66 or 110 block unless you pay them to extend the lines. If you normally do your own inside wiring, just order them to your demarc. If you want Verizon to extend them to where your video equipmet will be, they will be happy to do that and charge you an arm and a leg.
The lines can be installed on standard RJ-45 jacks. These are not "smart jacks". Each line uses one pair, just like an analog phone line but you can't use a butt-set to test them.
hope this helps....
If you are ordering three isdn BRIs, you will need to know what type of video equipment you are connecting to.
ISDN bri lines are "digital" phone lines. Verizon will deliver each line on a 66 or 110 block unless you pay them to extend the lines. If you normally do your own inside wiring, just order them to your demarc. If you want Verizon to extend them to where your video equipmet will be, they will be happy to do that and charge you an arm and a leg.
The lines can be installed on standard RJ-45 jacks. These are not "smart jacks". Each line uses one pair, just like an analog phone line but you can't use a butt-set to test them.
hope this helps....
- Thread starter
- #3
I wasn't sure if you were asked to order ISDN PRI lines for your PBX or BRI lines to plug directly in to your video equipment. I assume you are ordering BRI lines.
We have 3 ISDN BRI lines at two of our locations. The equipment takes these three lines and combines the bandwith in order to get better video quality. The software that comes with the equipment has a directory and we dial our remote site with.
You should coordinate with whoever is installing your video equipment. There are so many different flavors of ISDN, you should really understand what the equipment can handle before you order the lines.
We use the "National ISDN" standard and the switch type is "DMS 100".
Sorry if this is too confusing. Let me know if you need me to clarify anything.
P.S. A "smart jack" is used as a test point for the telephone companies when they drop off a T1 at your location. They can perform loopback tests, etc....
We have 3 ISDN BRI lines at two of our locations. The equipment takes these three lines and combines the bandwith in order to get better video quality. The software that comes with the equipment has a directory and we dial our remote site with.
You should coordinate with whoever is installing your video equipment. There are so many different flavors of ISDN, you should really understand what the equipment can handle before you order the lines.
We use the "National ISDN" standard and the switch type is "DMS 100".
Sorry if this is too confusing. Let me know if you need me to clarify anything.
P.S. A "smart jack" is used as a test point for the telephone companies when they drop off a T1 at your location. They can perform loopback tests, etc....
- Thread starter
- #5
your answer was perhaps the best, clearest and most concise answer I've received on tektips since I starting using this website. Thank you!! one little last question....is a smartjack ONLY used for testing T1s? if so, then why is my manager talking about having these three ISDN lines (he is also ordering 3 ISDN lines, sounds just like what you did) terminate in a smartjack? is it possible he doesn't know what he's saying?
- Thread starter
- #6
tcomanalyst,
I'm sure your boss, like many of us, use centain terms interchangeably. Don't get too hung up on the terms. They will drive you nuts.
Technically, smartjacks are used for T1s only. They are also known as the "Network Interface" or "NI". They are considered "smart" because you can perform remote tests to them among other things. Unlike regular phone jacks, these smart jacks have electronics in them that the phone company uses for testing and remote diagnostics. When you unplug your equipment from them, the phone company can tell. If your equipment is too far from the smart jack, they can boost up the signal, etc...
An ISDN jack is just like the ones you find in your house. They are made of wires and plastic. There's nothing "smart" about them.
You can find plenty of information about ISDN on the web but here are the basics:
An ISDN BRI is a line that has 2 "B" channels and one "D" channel. The B channels carry your voice or data and are 64Kbs each for a total of 128Kbs. When you order 3 BRI lines, you get a total of 384Kbs of bandwith. The D channel is used for signaling purposes.
In North America, a PRI is has 23 "B" channles and 1 "D" channel. If you do the math, you will see that a PRI has the same bandwith as a T1 1.54 MBps.
There's alot more to it than this. You should do a search on the Google. There's a ton of information out there you can read up on.
Good luck....
I'm sure your boss, like many of us, use centain terms interchangeably. Don't get too hung up on the terms. They will drive you nuts.
Technically, smartjacks are used for T1s only. They are also known as the "Network Interface" or "NI". They are considered "smart" because you can perform remote tests to them among other things. Unlike regular phone jacks, these smart jacks have electronics in them that the phone company uses for testing and remote diagnostics. When you unplug your equipment from them, the phone company can tell. If your equipment is too far from the smart jack, they can boost up the signal, etc...
An ISDN jack is just like the ones you find in your house. They are made of wires and plastic. There's nothing "smart" about them.
You can find plenty of information about ISDN on the web but here are the basics:
An ISDN BRI is a line that has 2 "B" channels and one "D" channel. The B channels carry your voice or data and are 64Kbs each for a total of 128Kbs. When you order 3 BRI lines, you get a total of 384Kbs of bandwith. The D channel is used for signaling purposes.
In North America, a PRI is has 23 "B" channles and 1 "D" channel. If you do the math, you will see that a PRI has the same bandwith as a T1 1.54 MBps.
There's alot more to it than this. You should do a search on the Google. There's a ton of information out there you can read up on.
Good luck....
- Thread starter
- #8
phonejack99
Technical User
Don't forget if you do infact wind up using BRI's you will also up using/needing NT1 devices -- sorta like a smart jack for the BRI's
- Thread starter
- #11
what do you mean by "used a T1 out of your PBX"? doesn't a T1 have 24 paths? You took a whole T1 for a video conference? I don't know much about video conferencing either, but I can't understand at all what you're describing. I am beginning to regret posting this message because with each answer I get more and more confused!
enrightdj
Technical User
- Sep 7, 2003
- 73
You would not use all the channels on the T-1 for the conferencing, it is just another way to access the PSTN without ordering new service.
You need to way the cost of the multiple ISDN lines vs ordering another T-1 circuit card for the PBX. Do you have enough local and long distance bandwith to allow video conferencing over these circuits? What type of video call are they trying to complete,128k,384 etc?
You need to way the cost of the multiple ISDN lines vs ordering another T-1 circuit card for the PBX. Do you have enough local and long distance bandwith to allow video conferencing over these circuits? What type of video call are they trying to complete,128k,384 etc?
I too am very new to this stuff.
ENRIGHTDJ, are you suggeseting that a T1 can be subdivided? Part of the T-1 can be used for ISDN and the residual can be use to support the PBX? If so, that would make a lot of sense and could save some money.
At my site, I have two T-1 connections. One for the LEC for in/out bound traffice and the second T1 goes to MCI for outbound long distance traffic. I suspect it is over-kill. We just inherited some video conferencing equipment. I was told that I'd need three dedicated ISDN lines to support the conference equipment. I did it without questioning. If I could subdivide my MCI circuit and use it for the conferencing, it could potentially save me some money. How does one go about subdividing? Some sort of splitter before the PBX or do the video conferencing lines come out of the PBX?
mike
ENRIGHTDJ, are you suggeseting that a T1 can be subdivided? Part of the T-1 can be used for ISDN and the residual can be use to support the PBX? If so, that would make a lot of sense and could save some money.
At my site, I have two T-1 connections. One for the LEC for in/out bound traffice and the second T1 goes to MCI for outbound long distance traffic. I suspect it is over-kill. We just inherited some video conferencing equipment. I was told that I'd need three dedicated ISDN lines to support the conference equipment. I did it without questioning. If I could subdivide my MCI circuit and use it for the conferencing, it could potentially save me some money. How does one go about subdividing? Some sort of splitter before the PBX or do the video conferencing lines come out of the PBX?
mike
enrightdj
Technical User
- Sep 7, 2003
- 73
Yes, you can split the T-1. Just remember, when doing a channelized T-1 vs ISDN the codec has to be setup properly when doing a video call. Channelized T-1's can only do 56k per channel where ISDN supports 64k per channel per call.
ISDN- 6 channels= 384Kbs
Channelized- 6 channels= 336Kbs
I have used Telco Systems products in the past to map the DS0's of a T-1 to multiple circuits. Adtran should have a product out there to support this as well.
ISDN- 6 channels= 384Kbs
Channelized- 6 channels= 336Kbs
I have used Telco Systems products in the past to map the DS0's of a T-1 to multiple circuits. Adtran should have a product out there to support this as well.
Why do we like BRI ISDN so much?
Because it's basically a phone call, except it's digital instead analog. ISDN BRI is way cool, it has 2 channels called B channels, they actually carry the data. And there is this other channel, it's the D channel, it carries signaling for call setup and teardown, that's why ISDN calls connect so quickly.
There's more to ISDN than setting up the call. You have to know the "ISDN Switch Type", the guy at the phone company tells you that. It could be an AT&T 5ESS or a DMS 100 or they have others too.
Some switches require you to configure SPIDs. On a BRI interface, you would need to configure a SPID for each B channel, but the phone guy will tell you if you need SPIDs. You also have to configure other stuff too, like a "dialer list" and don't forget you need an IP address too!
How would you go about configuring ISDN?
I'd configure the ISDN switch type first. You can do that globally or at the interface, it doesn't matter.
If you do it globally, it will be applied to all ISDN interfaces on the router, and if you configure the switch type at the interface, it applies only to that specific interface.
What is the command to configure the switch type?
That's easy, its "isdn switch-type" followed by the actual switch type, you can enter a question mark if you need help.
How would you configure SPIDs?
You have to go to the BRI interface, Always enter interface bri 0/0 and hit enter. Then you are at the BRI interface, it has these little parentheses and inside they say "config-if", anyway you have to configure 2 spids, but only if the telco switch requires it, you go isdn spid1 and enter the SPID number then go isdn spid2 and enter the other SPID number. It's pretty simple.
What's next?
Now would be a good time for an IP address, you would enter ip address 172..16.1.1 255.255.0.0 and push down on the enter key again. Here is where you enter the encapsulation, go encapsulation ppp and hit enter. ppp encapsulation lets you do authentication. Next enter ppp authentiction chap
Authentication? What for?
ISDN is essentially just a telephone call. Do you want every gnarly surfer dude from the valley calling your router? No waa-aay! Next thing to configure is a dialer list to define interesting traffic.
Interesting traffic?
ISDN is expensive, you pay by the minute and it can really add up. Your ISDN interface will establish a connection every time it receives traffic destined for whatever networks are at the other end of the link. Lets say a network at a very remote office runs IPX and IP, but you only want IP traffic to bring up the link, so you must define IP as being interesting, get it? You do it with a "dialer list" it works kinda like an access list. In global mode you would enter the following:
dialer-list 1 protocol ip permit
Then you go back to the interface mode and apply it like you do an access list:
dialer-group 1
But that seems kinda broad, permitting the entire IP suite, is there a way to be more granular about what constitutes interesting traffic?
Definitely! You can make a sub routine call to an extended ip access list:
dialer-list 1 protocol ip list 101 Pretty cool, huh? You can't get much more granular than an extended access list!
What do you configure next?
You need to map the layer 3 IP address of the next hop router to the layer 2 address of the ISDN phone numbers that you want the router to dial to reach that IP address. Pretend that the dialer string you want is 55512121010 and the interface at he other end of the link has an IP address of 172.16.1.2 Also pretend the the router at the other side of the link is called "denver". This uses the dialer map command, here's how to do it:
dialer map ip 172.16.1.2 name denver 55512121010
Do you mind showing us a ISDN config?
This is all easy, it was on the CCNA test, there is lots more to configuring ISDN, but here's a general config:
!
isdn switch-type basic-5ess
!
interface bri 0/0
ip address 172.16.1.1 255.255.0.0
encapsulation ppp
dialer map ip 172.16.1.2 name denver 55512121010
dialer-group 1
ppp authentication chap
!
dialer-list 1 protocol ip permit
Because it's basically a phone call, except it's digital instead analog. ISDN BRI is way cool, it has 2 channels called B channels, they actually carry the data. And there is this other channel, it's the D channel, it carries signaling for call setup and teardown, that's why ISDN calls connect so quickly.
There's more to ISDN than setting up the call. You have to know the "ISDN Switch Type", the guy at the phone company tells you that. It could be an AT&T 5ESS or a DMS 100 or they have others too.
Some switches require you to configure SPIDs. On a BRI interface, you would need to configure a SPID for each B channel, but the phone guy will tell you if you need SPIDs. You also have to configure other stuff too, like a "dialer list" and don't forget you need an IP address too!
How would you go about configuring ISDN?
I'd configure the ISDN switch type first. You can do that globally or at the interface, it doesn't matter.
If you do it globally, it will be applied to all ISDN interfaces on the router, and if you configure the switch type at the interface, it applies only to that specific interface.
What is the command to configure the switch type?
That's easy, its "isdn switch-type" followed by the actual switch type, you can enter a question mark if you need help.
How would you configure SPIDs?
You have to go to the BRI interface, Always enter interface bri 0/0 and hit enter. Then you are at the BRI interface, it has these little parentheses and inside they say "config-if", anyway you have to configure 2 spids, but only if the telco switch requires it, you go isdn spid1 and enter the SPID number then go isdn spid2 and enter the other SPID number. It's pretty simple.
What's next?
Now would be a good time for an IP address, you would enter ip address 172..16.1.1 255.255.0.0 and push down on the enter key again. Here is where you enter the encapsulation, go encapsulation ppp and hit enter. ppp encapsulation lets you do authentication. Next enter ppp authentiction chap
Authentication? What for?
ISDN is essentially just a telephone call. Do you want every gnarly surfer dude from the valley calling your router? No waa-aay! Next thing to configure is a dialer list to define interesting traffic.
Interesting traffic?
ISDN is expensive, you pay by the minute and it can really add up. Your ISDN interface will establish a connection every time it receives traffic destined for whatever networks are at the other end of the link. Lets say a network at a very remote office runs IPX and IP, but you only want IP traffic to bring up the link, so you must define IP as being interesting, get it? You do it with a "dialer list" it works kinda like an access list. In global mode you would enter the following:
dialer-list 1 protocol ip permit
Then you go back to the interface mode and apply it like you do an access list:
dialer-group 1
But that seems kinda broad, permitting the entire IP suite, is there a way to be more granular about what constitutes interesting traffic?
Definitely! You can make a sub routine call to an extended ip access list:
dialer-list 1 protocol ip list 101 Pretty cool, huh? You can't get much more granular than an extended access list!
What do you configure next?
You need to map the layer 3 IP address of the next hop router to the layer 2 address of the ISDN phone numbers that you want the router to dial to reach that IP address. Pretend that the dialer string you want is 55512121010 and the interface at he other end of the link has an IP address of 172.16.1.2 Also pretend the the router at the other side of the link is called "denver". This uses the dialer map command, here's how to do it:
dialer map ip 172.16.1.2 name denver 55512121010
Do you mind showing us a ISDN config?
This is all easy, it was on the CCNA test, there is lots more to configuring ISDN, but here's a general config:
!
isdn switch-type basic-5ess
!
interface bri 0/0
ip address 172.16.1.1 255.255.0.0
encapsulation ppp
dialer map ip 172.16.1.2 name denver 55512121010
dialer-group 1
ppp authentication chap
!
dialer-list 1 protocol ip permit
t-
The first place to start is with the video conference manufacturer. Ask them to go over the connectivity requirements for the equipment in full detail. Next, determine if you have any PRI circuits on your PBX. If you do, you can get a BRI-U or BRI-T interface card (depending on the requirements of the video conf equip) for the PBX and create your own BRI lines. If you don't have a PRI, you'll use the information provided by the video conf manufacturer to order BRI lines from Verizon.
The first place to start is with the video conference manufacturer. Ask them to go over the connectivity requirements for the equipment in full detail. Next, determine if you have any PRI circuits on your PBX. If you do, you can get a BRI-U or BRI-T interface card (depending on the requirements of the video conf equip) for the PBX and create your own BRI lines. If you don't have a PRI, you'll use the information provided by the video conf manufacturer to order BRI lines from Verizon.
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