T1 (cas), rj48c

cerberos

Hello everybody, recently a friend of mine shared me with a weird story that happened between him and his ISP... The story started when he told me that they are going to suscribe for a T1 CAS Connection to connect his small company for their Central Office... He asked me for a spare WIC-1T, and I told him why do you need to go with this old card, why not buy a WIC-1DSU-T1, too cheap on eBay right now, and won't need CSU/DSU because it has an integrated CSU/DSU already, density and low cost... Finally, he got convinced and bought the card...

Just 2 days later, a tech, who calls himself a tech, came and delivered a CSU/DSU... My friend asked so what is this? The tech said, don't worry this is a CSU/DSU needed for the DS1, clocking and bla bla bla, so my friend answered saying we don't need it since and we have a card that has it integrated... The tech said don't worry, this is already included on the price's backage, so my friend answered it's fine but I only need the RJ48C cable... To make the story shorter, after alot of calls and b9llshit, the tech and all network engineer at the ISP said we are sorry, we don't provide an RJ48C cable, if you are going with Cisco then we recommend going with the old DB60 card and get urself a DB60 to V.35 cable so you can make your CAS connection to work... Is there anything in the whole universe like this? Someone please explain to me, maybe I'm wrong or over reacting, or maybe even I studied wrong! I Know that there is alot of standards that will connect a router to the CSU/DSU in case of the absence of a Card that has an integrated CSU/DSU... So here is the topology, to my knowledge :

With WIC-1T :

Router(WIC-1T)---->(V.35 PLUG)CSU/DSU(RJ48C)---->RJ48C Wall Jack.

With WIC-1DSU-T1 :

Router(With WIC-1DSU-T1)---->RJ48C Wall Jack.

Isn't it a standard or what we are studying in books is different from the real world?! Thanks in advance brothers.

Kaminsky

Demarc !

Your ISP will deliver a circuit to their own NTU how they see fit. You typically have a small set of presentation options as to how you want connect to that ntu which you must specify when ordering the circuit from them. Typically, a T1 will be DB15 which the customer then connects to with their own db15 to db60/Smart Serial cable into their router. The demarc (their responsibility with any future problems) will be the presentation port they have activated. From the cable onwards, it is the curstomer's problem. Don't underestimate the importance of this.

There is a lot of money in WAN communications and who's fault it is when the circuit fails needs to be clearly defined and cannot be messed about with. You can't just come up with something else on the spot when the engineer turns up ( no matter how obvious your idea of the technology may see it ) or that line will get muddied and cause later arguments which a carrier will not even consider getting into. They deliver these circuits these ways and it's up to you to connect to it in one of those ways.

Also, don't overestimate the networking knowledge of the carrier engineer that turns up to commission the circuit. He has a very clear job which is not open to on the spot negotiations. They are there to install the wiring from the exchange, fit the NTU and then make sure the port works within tollerances. That's all. If you wanted a presentation dissimilar with what they usually provide, that should have been specified when ordering the circuit. It would undoubtedly cost you more for doing this.

And for the love of god, don't buy a business's WAN router interface card off ebay. Buy a new one that you have a manufacturer's warranty on. Ebay interfaces are good for labs.. yes.. Businesses, your friend would be laughed out of the building. The carrier finds out you did this, any future problems with that circuit would immediately be blamed on that interface first and you would have to go to hell and back proving your ebay interface was not the problem before you could get a carrier engineer out to look at the problem.


EDIT: I didn't intend this post to sound negative and I do understand what you meant by

cerberos wrote: »

Isn't it a standard or what we are studying in books is different from the real world?! Thanks in advance brothers.

where the CSU can be omitted if the customer's devices (interfaces) are already T1 ready. In reality, the carrier will present their circuit a certain way with a physical NTU and it's CSU and that's the end of it.

tiersten

What Kaminsky said.

Also you can't just blindly buy a WIC-1DSU-T1. If it is a newer router then it will need a WIC-1DSU-T1-V2.

cerberos

Kaminsky wrote: »

Demarc !

Your ISP will deliver a circuit to their own NTU how they see fit. You typically have a small set of presentation options as to how you want connect to that ntu which you must specify when ordering the circuit from them. Typically, a T1 will be DB15 which the customer then connects to with their own db15 to db60/Smart Serial cable into their router. The demarc (their responsibility with any future problems) will be the presentation port they have activated. From the cable onwards, it is the curstomer's problem. Don't underestimate the importance of this.

There is a lot of money in WAN communications and who's fault it is when the circuit fails needs to be clearly defined and cannot be messed about with. You can't just come up with something else on the spot when the engineer turns up ( no matter how obvious your idea of the technology may see it ) or that line will get muddied and cause later arguments which a carrier will not even consider getting into. They deliver these circuits these ways and it's up to you to connect to it in one of those ways.

Also, don't overestimate the networking knowledge of the carrier engineer that turns up to commission the circuit. He has a very clear job which is not open to on the spot negotiations. They are there to install the wiring from the exchange, fit the NTU and then make sure the port works within tollerances. That's all. If you wanted a presentation dissimilar with what they usually provide, that should have been specified when ordering the circuit. It would undoubtedly cost you more for doing this.

And for the love of god, don't buy a business's WAN router interface card off ebay. Buy a new one that you have a manufacturer's warranty on. Ebay interfaces are good for labs.. yes.. Businesses, your friend would be laughed out of the building. The carrier finds out you did this, any future problems with that circuit would immediately be blamed on that interface first and you would have to go to hell and back proving your ebay interface was not the problem before you could get a carrier engineer out to look at the problem.


EDIT: I didn't intend this post to sound negative and I do understand what you meant by

where the CSU can be omitted if the customer's devices (interfaces) are already T1 ready. In reality, the carrier will present their circuit a certain way with a physical NTU and it's CSU and that's the end of it.

First of all Kaminsly, let me thank for your post... I know how frustrating this topic is, the demarcation point... That's a very long debat that will never end, still on hot debat and will be till God wills for it to end...

Sounds funny when both engineers, on both side (ISP&Client) will blidnly start to close their mind, and trying their best only to prove that his network is in good hands, he is intact and for sure the problem is on the other side, without invastigation or even have a look on the problem sometimes... And I don't blame them sometimes, however one of them is always the reason and to prove it is not an easy matter... The problem is always a lost credibility due to bad experience with some clients or some ISPs on both sides... At least you can chose your ISP, but poor ISP, he can't chose but any client, or he will lose business.

Thanks alot Kaminsky, tiersten appreciated alot your input guys, well versed post kaminsky...