Re: Routing -- this will work, won't it??

Dave Siegel (dsiegel@rtd.com)
Mon, 20 Nov 1995 20:17:56 -0700 (MST)

> ISP currently using one Internet T-1 with managed (rented) Cisco 2501 router
> and ADC Kentronix DSU/CSU.
>
> Going to get a redundant T-1 from a competing big guy telco. However, they
> don't "do" managed routers and DSU/CSU's.
>
> The company that we're talking to for the redundant T-1 recommends a Cisco
> 4000 w/32M RAM for "border gateway routing" -- smart routing that will route
> telco A's customers off on telco A's existing T-1 and telco B's customers
> off on the
> new telco B T-1. Bottom line price tag for Cisco and DSU/CSU is about $12K.

Baloney...you don't need that kind of hardware. Try Popping a 16MB SIMM into
your 2501 (be careful which brand...cheaper models don't work).

> I've got this idea that will save the boss some bucks if it will work (and I
> don't see
> why it won't).
>
> I've got 12 PM2E's that use the existing 2501 router for default gateway.
> Why can't
> I buy another 2501 and a simple Motorola FT-100S DSU/CSU for the new T-1,
> route half
> my PM2E's thru the existing router and the other half thru the new router??
> Prudent use of default gateway in the PM2E's would/could balance the load
> between
> the routers.

For outbound traffic, yes, but you'd have to have different networks routed
in through each gateway to get the same balancing on the way back in.

You also don't gain the benefit of having the two links, only that you have
twice as much bandwidth. If one goes down, half your customers are down,
and if the other goes down, the other half goes down. Furthermore, since
they are logically seperate networks, and the T1's aren't connected, you
can't get the closest route to the destination for the whole network combined.

This may be inconvenient, or it may not be a big deal at all.

Regardless, it's not difficult to dual-home out of a Cisco 2501 w/16MB.

btw, this isn't really a livingston question at all.

> This scenario will cost $4K max. It's not "intelligent" routing like BGP4,
> but the
> $8K difference would mean a lot to the boss.

How about another $1500 instead of $4k or $14k?

If you'd like setup details, I have a tutorial written specifically for
dual-homing with a Cisco.

Dave

-- 
Dave Siegel		     President, RTD Systems & Networking, Inc.
(520)623-9663		     Network Engineer -- Regional/National NSPs (Cisco)
dsiegel@rtd.com		     User Tracking & Acctg -- "Written by an ISP, 
http://www.rtd.com/~dsiegel/					for an ISP."