Cell Relay Archive

["Kevin Fleming" <no@spamming.now>]

Fahad A Hoymany wrote in message <6p1v8n$348$3@usenet01.srv.cis.pitt.edu>...
>Hi,
>
>        Our network provider says they cannot provide us with an optical
>interface to their network.  They can only give us an E3 electrical
>interface.

It looks like they have only E3 ports available to you, the user, or there
are some regulatory/commercial reasons why they don't want to offer STM-1,
or they have to carry you over a transmission system to you local Point of
Presence (which my not be as close as you think...)
The E3 is carried over fibre, to be sure, to you local exchange - but it
sounds like it is then carried over SDH to the ATM switch.

> We want an STM-1 interface (155Mbps) but it seems that Cisco
>does not have electrical interfaces for that speedit only has optical
>interfaces for STM-1.  The questions are:
>

Do you need 155Mbps of bandwidth...?

>1. Does it matter if you use electrical or optical STM-1 interface?

Electrical STM-1 operates to a couple hundred metres (or even less, not too
sure) over coaxial cable.  It is a common interface on SDH line systems
which are intended for intra-office use (office=exchange)

>2. If they give us an electrical interface to their network, does that mean
>the actual signal over the fiber link (into their network) is electrical?
>Is it even possible that an electrical signal be carried over a fiber line?
>

I refer you to James Carlson's responses to these questions .

>Thanks in advance
>Fahad
>

Hope this helps,
Kevin.