[nsp] Is default failover in dual-homed DSL possible?

[Mike Smith]

www.mexland.com has a very nice solution that would fit your scenario. They
have a dual port wan firewall that will load balance across the two WAN
ports, in addition you can connect a external dial-up modem to the serial
port on this device in the event both DSL connections fail it will
seamlessly pick up the phone line and connect to a ISP. Once DSL service has
been restored it will detect that as well and drop the dial-up connection.


----- Original Message -----
From: "Furnish, Trever G" <TGFurnish@herff-jones.com>
To: <booloo@ucsc.edu>; <cisco-nsp@puck.nether.net>
Sent: Friday, December 20, 2002 10:07 AM
Subject: RE: [nsp] Is default failover in dual-homed DSL possible?


> Can you configure the DSL modems to drop the router side of the connection
> when the ISP side drops?
>
> Are the "modems" themselves capable of running a routing protocol with
your
> router?  Some of them are - but most aren't. :-)
>
> > -----Original Message-----
> > From: Mark Boolootian [mailto:booloo@ucsc.edu]
> > Sent: Monday, December 16, 2002 7:24 PM
> > To: cisco-nsp@puck.nether.net
> > Subject: [nsp] Is default failover in dual-homed DSL possible?
> >
> >
> >
> > Folks,
> >
> > I'm looking for a solution for home/business DSL users who
> > want dual-homed
> > DSL connections to protect against outages.  The basic
> > picture looks like
> > this:
> >
> >
> >        ----------         -----------
> >        |  ISP 1 |         |  ISP 2  |
> >        ----------         -----------
> >            |                    |
> >            |                    |
> >            |                    |
> >           -----               -----
> >           |   |               |   |  <- DSL modems
> >           -----               -----
> >              \               /
> >              ----------------
> >              |   router     |
> >              ----------------
> >                     |
> >                     |
> >             --------------------
> >
> > The router is doing NAT, and there is no dynamic routing
> > protocol running
> > between the router and the ISPs (i.e. typical home DSL
> > setup).  The question
> > is, are there any products/mechanisms for allowing a static
> > default pointing
> > at one ISP to failover to the other ISP in the event of a
> > network outage
> > at the first ISP?
> >
> > In the above diagram, a failure with DSL would take down the
> > PPP connection,
> > so presumably if the DSL modem were built-in to the router,
> > the router would
> > notice that the PPP connection was down, and perhaps the
> > right thing could be
> > made to happen.  Unfortunately, I don't know of a small
> > router that would
> > accommodate this solution.  I suppose if one were to
> > terminate each DSL
> > connection in an individual router, and then feed both those
> > connections into
> > a third router, one might be able to manufacture something
> > that would work,
> > but I don't think I'd want to put that on my resume (much
> > less mention it on
> > this list).
> >
> > In order to accomodate failures beyond a dead DSL link, I've
> > got a rather
> > messy idea in my head of a box sitting on the LAN pinging
> > nameservers in each
> > of the ISP's networks, and making routing changes on the
> > router accordingly.
> >
> > Has anyone on this list set up anything to deal with such a situation?
> >
> > Thanks very much,
> > mb
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