Well, it's not necessarily true that a T1 circuit is a frame circuit. A T1
is simply the layer 1 technology. In other words, just a piece of wire more
or less. Frame relay on the other hand is a layer 2 technology. It will
typically run on T1 layer 1 technology but not always. There is a 56k
flavor of frame available and this is not run on a T-carrier circuit.
What layer 2 encapsulation does a "standard" T1 use if not frame relay you
ask? Usually HDLC. In fact, when setting up a serial interface on a Cisco
router in preparation for a T1, full or fractional, the default layer 2
encapsulation is HDLC and not frame relay. You can run PPP on a T1. This
is typically used when your upstream router is a non-Cisco router as Cisco's
HDLC is proprietary and not compatible with another vendor such as Nortel.
When somebody says "I have a T1 to the Internet", they are usually bragging
about the size of their "pipe", which is roughly 1.5Mbs for a full T1. The
fact that it's a circuit providing access to the Internet has nothing to do
with the layer 2 encapsulation as it could be FR, HDLC, or PPP. That was
not always the case as the frame relay "cloud" was just recently introduced
to the Internet "cloud", so now many ISPs will provide access via their
private frame relay network.
Good luck!
Rik
-----Original Message-----
From: Sam [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 28, 2001 7:06 PM
To:
Subject: Re: T1 concept? [7:10300]
There really is no difference between a T1 to your ISP or a T1 to a branch
office (in the scenario you outlined).
Of course the one obvious difference is that the T1 to your HQ is part of
your corporate "frame relay cloud" and the T1 to the internet is part of
your ISPs frame relay cloud.
T1 are usually frame relay connections, therefore they use frame-relay
encapsulation.
""RJ"" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Hello,
>
> What is the difference between a frame connection to a branch office (I
have
> configured this) and T1 to the internet (I don't know how this is
> configured).
> I have heard that our company has a T1 from a (HQ)Atlanta to
> (backoffice)Tampa.
> Also they have a T1 to the internet.
> They also have numerous frame connections to small offices through out the
> country.
>
> When somebody says that they have a T1 to the internet what exactly does
> this mean? What protocols (encapsulation) are they running? Is it PPP or
is
> it a frame connection? How does one connect to the ISP?
>
> I am sure these questions have simple answers. Can somebody please explain
> this concept?
>
> Thanks in advance.
>
> Regards,
>
> RJ.
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=10366&t=10300
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