WAN cabling and protocols

[a.azab]

Hi All,

I have been reading WAN technologies for the last month and got various questions, where I would deeply appreciate your help.

1- In leased lines technology, it can be used to connect into two sites or connect to the Internet. When connecting two sites, we use dedicated lines that are not used by anyone beside the two customers. 

             A) Is there any limitation what cable to use as a local loop (when connecting a customer to the ISP)? Fiber, T1, Radio?

             B) When using leased lines to connect to the Internet, the dedicated line only is the part between the customer and the ISP. When leaving the ISP to the Internet, it will be shared with other customers. Right?

2- Is there any limitations in which cabling to use when connecting to the ISP over Frame Relay (local loop cabling)? (are we limited to T lines or we can use fiber, radio connections...etc).

3- Is the reason that many books and sites mention T lines when connecting to the ISP is its availability by the service providers?

4- I read that DSL is a shared line between other customers? How is that possible where the phone line is dedicated to per user?

5- Are T lines phone lines? If so, how are they different from the DSL lines then?

6- When using MPLS, can we connect two sites together, where one site uses Frame Relay to connect to the ISP and the other uses leased fiber cable?

Thanks,

Ahmad

[Leo Laohoo · Accepted solution]

we use dedicated lines that are not used by anyone beside the two customers. 

Well, the lines might look point-to-point but when it hits the PE of the ISP it's not necessarily a "dedicated" line.  

Is there any limitation what cable to use as a local loop (when connecting a customer to the ISP)? Fiber, T1, Radio?

Cost and speed.  Heck, you can go to Telstra and Optus and ask them for a Frame Relay service or an SNA/SDLC, MATIP or x.25 line but it'll cost an arm-and-a-leg (to maintain and operate) and it'll be mighty slow. 

When using leased lines to connect to the Internet, the dedicated line only is the part between the customer and the ISP. When leaving the ISP to the Internet, it will be shared with other customers. Right?

From CE to PE it's a dedicated line.  Once inside the PE it's a different story.

3- Is the reason that many books and sites mention T lines when connecting to the ISP is its availability by the service providers?

Y'mean T1/T2?  Yeah, because the book is based on US standard.

4- I read that DSL is a shared line between other customers? How is that possible where the phone line is dedicated to per user?

Nope.

Are T lines phone lines? If so, how are they different from the DSL lines then?

Yes.  Look it up.  Google it. 

6- When using MPLS, can we connect two sites together, where one site uses Frame Relay to connect to the ISP and the other uses leased fiber cable?

Yes.  If site A is located in a big city (like Sydney CBD) and site B is located, for example, 200 kms west of Orange and the nearest exchange is a remote exchange unit. 

[a.azab]

Leo,

Thanks for the reply mate. 

Regarding question 4, many links refer to the broadbankd conenction as shared, ideas?:

https://www.linkedin.com/pulse/what-differences-between-broadband-leased-line-jonny-rae

https://www.concertnetworks.co.uk/blog/3-differences-between-broadband-and-leased-lines

[Leo Laohoo]

I misread #4. 

Yes, it's a shared line.  Point-to-multi-point connection.