Network Topology

I need the expert advice from all of you in this issue since my experience
is insignificant compared to some of the members of this list. In your
experience what is better in terms of connectivity to the Internet. My boss
wants me to order 4 T1's (maybe 6) to different providers to be
'completely' sure that our NOC will 'always' be up & running. I've already
got 2 T's right now, I really don't know how' 'wise' it is to add another
4 or 6 from 'different' providers. Would it be better for us to get them
from the same 2 upstreams we've already got? Would it be better to get a
Fractional T3? I need some convincing arguments for him to understand, can
anyone help?


my biggest concerns would be the following:

  1) Fiber Cuts that take out your t1's
  2) Power Outages
  3) Router Failures

  Getting a few t1's from different providers will help,
yes, as it will provide you the ability to manage your network
such that if one provider has a failure, you can
use the others, assuming they are bgp4+ speakers and you can
do proper automatic failover.

  Do you have LEC fiber on premise? is it properly protected?
Do you have proper generators, batteries, etc.. to keep
this alive? Do all your t1's come in on that, or on a similar lightspan unit?

  If you have (for example) MFS + (insert other LEC here) on premise
and bring your t1's in on seperate carriers to providers who are on those
carriers, (ie: saying on MFS/LEC fiber to other provider), you'll
be in good shape barring a bomb threat, fire, or chemical spill.

  - Jared

On Wed, Mar 24, 1999 at 11:08:39AM -0500, Jared Mauch babbled:

  my biggest concerns would be the following:

  1) Fiber Cuts that take out your t1's
  2) Power Outages
  3) Router Failures

even simpler than that. you need to make sure your ds1 is coming from
differnt physical entry points of the facility from different CO's.
one drunk running into the telephone pole outside your place, or a
flood in the utilities under the streets can wipe you out if there
aren't multiple paths.

an absolute fallback would then be a uhf/microwave link to another
facility which now a days can do 10Mb/s for not too much $$.


I think you have the wrong idea on this T-1 thing. If a fiber cut is
taking out your T-1's, as Mr. Mauch was saying. Then you would have a SONET
entrance facility from the LEC into your building. Having the LEC build
the entrance as a bidirectional ring with diverse physical entry points
into the building is the way to go. The only way a T-1 can be dropped due
to a fiber cut is if the build is Linear or the transport provider built a
single physical entry point (which is shady to say the least!).

Jody Craft