Re: Frame Relay Connections...

[Richard Lohman <rjlohman@xxxxxxxxx>]

Hi Brian.
    We have a WAN here at work based on Frame Relay, so I'll give you
what I know. First of all, FR is a shared service. That is, you will
be sharing space on the FR switch (located at your Telco) with other
organizations who also have FR circuits. You will NOT be sharing data,
packets, etc., just bandwidth. FR is also a variable-bandwidth
service. In other words, When you purchase a 128K circuit, you are
usually *guaranteed*, at a minimum 64K. 128K is your maximum
bandwidth, when no one else is using the shared circuit. There's a
report you can request from you r service provider called a Committed
Information Report (CIR) that tells what your actual throughput is.
This basically translates into a cheaper connectivity option (much
cheaper than running a dedicated fractional T-1). On the plus side,
there is one distinct advantage to FR that I really like. In other
internetworking schemes, when a packet must travel from points A to B,
to C, then to D, each node relaying the packet performs error checking
with the receiving node. Hence, A transmits the packet to B, and
before B can transmit to C, it does error checking with A to insure
the packet's integrity. In FR, The packet is forwarded through the
system to D, then D does error checking with A. In a system with few
physical errors in the circuits, this is a dramatic decrease in traffic.
    As far as interfacing, FR is independent of the operating system
and computer architecture. Access to FR is achieved with a CSU/DSU and
a router. The parameters for the FR circuit are configured in the
router. Hence, if you want to run Token Ring, Ethernet, TCP/IP,
NetWare, or whatever, it all goes over FR.

For more technical information, there's a very nice document at Cisco:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/55149.htm

Hope this helps.
:Rich


---"Brian D. Cook" <sales@greertoyota.com> wrote:
>
> We are going to be getting one at work.  I was wondering what anyone
knows about this type of connection.  Is it a pci/isa card that goes
into the box?  Is it a standalone device?  Is it  a router or csu?  My
isp is going to be also getting me this information, but I was
wondering what (if any) experience anyone had with this type of
connection and linux?  if it's an internal device I have read the
net-3 howto and seen that the kernel would have to be reconfigured. 
But would it have to be if it's a external device?  Any "real world"
information about it would be most useful.
> 
> Thanks in advance
> 
> Brian
>
==
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| Richard J. Lohman        | If you always do what you've |
| Network Engineer         | always done, you'll always   |
| Data Processing Dept.    | get what you've always       |
| Porter County, IN        | got.                         |
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