Re: Multiple upstreams

Phillip Heller ( (no email) )
Mon, 10 Aug 1998 13:40:45 -0400

Look into the following:

Cisco 2611 (comes with two 10 Base T interfaces)
WIC-1B-U (one port ISDN BRI with NT1)

and when you're ready to add your own T1:

WIC-1DSU-T1 (single T1 interface with integraded CSU/DSU)

You'll also probably want the IP+ version of CISCO IOS for the added memory

If you take customer routes from PSI via BGP, then PSI's border router which
is connected to your border router will tell your router via BGP of all the
routes that are directly connected to PSI's network. You would want to do
much the same thing with your friend that you're pulling the ethernet from.


ISP-A is connected directly to Verio in Los Angeles
ISP-B is connected to PSI out of Washington DC.

If you have taken customer routes and a packet originates from your network
with a destination of ISP-B, your router will know enough to send the packet
through the PSI connection because PSI's router has told your router that
ISP-B is directly connected to another router in it's AS.

Now of course, if one connection dies, your router will know enough to start
sending all the packets through the remaining active connection.

Customer routes doesn't guarantee the fastest routing for all packets, but
it certainly does improve perfomance.


PS - the NTISP list probably isn't the place to discuss routing and the
such.... if you have any more questions, please email me privately.

-----Original Message-----
From: Stuart Stevenson <>
To: <>
Date: Monday, August 10, 1998 11:20 AM
Subject: Re: Multiple upstreams

Thanks for the quick response!

Can you recommend which Cisco router should I be looking at? It sounds like
I'd need the following interfaces: BRI-U (for ISDN), 2 10-B-T (from the
neighbor and for my local net), and preferably a serial interface so I could
get my own T1 when the time comes. I guess I could also use an external NT1
into a serial interface too.

Also (ignorance exposed), what do you mean by "customer routes from PSI",
does that refer to them setting up their routers to route to a "customer
owned" address block (really a Verio block in my case)?

*********** REPLY SEPARATOR ***********

On 8/10/98, at 1:12 AM, Phillip Heller wrote:

>I would look into attaching that 128k ISDN line to the Cisco box and run
>BGP4. Of course 128k ISDN hardly offsets the speed of the T1, but if you
>took customer routes from PSI, you might improve efficiency a bit, and
>redundancy _quite_ a bit. Of course you'll need to get PSI and your new
>found friend to do BGP sessions with you.
>Good luck either way!
> Phil
>-----Original Message-----
>From: Stuart Stevenson <>
>To: <>
>Date: Sunday, August 09, 1998 11:20 PM
>Subject: Multiple upstreams
>We're currently doing a little web hosting via a 128k ISDN and an Ascend
>Pipe 50. We have a class C from PSI and have been humming along just fine.
>Now we're starting to feel the pressure to add bandwidth and have struck a
>deal with a neighbor to pull in a 10-Base-T cable from his 2 T1s.
>The plan is to use a Cisco router between our suite and theirs. We can get
>another Class C from these guys, but we would also like to keep the PSI
>connection as a backup.
>We've got a few questions on how to do all this:
>1) Is it possible (and reasonable) to have both connections active at the
>same time?
>2) If so, can we do it and keep the PSI address block with routing via the
>new upstream (which is connected to Verio) or get PSI route to our Verio
>3) If not, is it reasonable to setup two subnets (1 PSI block and 1 Verio
>block) with each virtual server assigned an address in each subnet? I am
>thinking if we do it this way, I could have our primary DNS on the Verio
>subnet, pointing to Verio addresses, with our "secondary" setup as a
>on the PSI subnet, with all it's A records pointing to the PSI block. I
>know it's twice the work, but (to me anyway) it makes sense and would
>provide complete connection redundancy.
>Any thoughts from some seasoned pros?
>Stuart Stevenson
>Tracent Technologies, Inc.