T1

[gurkamal01]

Hi

i am sorry i am confused about the wan technologies mentioned in the ccna book i have

Is T1 a dedicated lease line or a packet switched or a circuit switched ISDN technology?

Is it used on a synchronous serial interface of a router?

please help

[scottmac]

A T1/DS1 is just a Layer one connection (operating in a TDM environment).

They can be point-to-point, using something like Cisco's flavor of HDLC, or it can be connected to a "cloud" (shared media) like Frame Relay (which can be a logical point-to-point or point-to-multipoint).

When used as a point-to-point with HDLC or PPP, it connects through a synchronous serial interface ... in some cases the CSU/DSU is built in, and the T1 connects directly into an RJ48 port of the router instead of through an external CSU/DSU (which then connects to the router via Sync Serial).

Even though a T1 and a North American ISDN Primary Rate Interface (PRI) share common parameters like line code and framing (B8ZS/ESF, for example), the "language" they each speak (above layer one) is completely different and NOT compatible.

Good Luck

Scott

[gurkamal01]

Hi

appreciate your response

i just read T1 is a PRI connection type

As i read PRI has 2 connection types

1.T1

2.E1

Thanks

[Rick Morris]

A PRI is a ISDN. It comes in the form of a T-1 but the common name is not T-1, although it appears the same, and is in essence a T-1 just how it is provisioned.

A T-1 can be set up several different ways, it all depends on the application on how it is built and set up.

[gurkamal01]

hi

thanks

so you mean T1 and T-1(ISDN) are 2 differnt things right?

[Rick Morris · Accepted solution]

It really is verbage/symantics.

A T-1 can be a point to point, dedicated, leased, frame relay, isdn.

It is an interchangable term. It is what the line is configured as by the LEC and what your application is.

For example:

A PBX to PBX line would be called a T-1 TIE line.

A T-1 running through a Frame Cloud would be a Frame Relay T-1

A PRI is a ISDN T-1

A BRI is a ISDN T-1

and so on.

Does that help?