Configuring multi-home failover

I am wanting to configure a secondary ISP to be used as fail over only for
our primary. At this point both ISP's come into the same 7500 router and I
have an established BGP session with our primary provider.

Can those of you doing this already tell me the optimum way to set this up?
Is this best done on my end or by having my secondary discover our
disappearance and begin announcing?

New territory for me so BGP configuration examples are welcome.

Regards,

Mike Stubbers
Network Analyst Supervisor, SCP
Information Technology Services
University of Idaho
mikest@uidaho.edu

Two very good guides for this:
http://www.nanog.org/mtg-0110/ppt/smith.pdf
and
http://www.cisco.com/public/cons/isp/documents/Multihoming_Draft_2_0.PDF
and basically all the documents in
http://www.cisco.com/public/cons/isp/documents
are worth the read.

Enjoy.

I am wanting to configure a secondary ISP to be used as fail over only for
our primary.

Most people who have two links use them also for load-sharing. A link to an
ISP is expensive enough so you don't want to keep it unused "just in case".

Is it because the second ISP charges a lot according to the volume actually
transfered?

At this point both ISP's come into the same 7500 router

So much for the redundancy.

have an established BGP session with our primary provider.

Do you have a private AS number or already a public one?

Can those of you doing this already tell me the optimum way to set this up?
Is this best done on my end or by having my secondary discover our
disappearance and begin announcing?

I would say that it is better done on your end because it will allow you to change your policy (see above my remarks). Also, it is "the normal way" of operation for BGP.

Stephane Bortzmeyer
To: Mike Stubbers

> I am wanting to configure a secondary ISP to be used as fail
over only for our primary.
Most people who have two links use them also for load-sharing. A
link to an ISP is expensive enough so you don't want to keep it unused

"just

in case". Is it because the second ISP charges a lot according to the
volume actually transfered?

Given our rural location, the high cost is in the circuit not the service.
We have contracted with a local ISP to utilize their bandwidth, but they do
not have continued capacity to support load balancing effectively. When our
primary fails we understand our secondary will become saturated as well
upstream. Not a pretty solution, but affordable for the moment. So yes, we
need to use this as backup only. The pricing model has this built in.
We'll pay very little to have the reserve in place, but face penalties when
utilized.

> At this point both ISP's come into the same 7500 router. So much for

the redundancy.

Agreed, see affordable note above. Historically most of our outages have
come from a local farmer during spring work, or a redneck with a shotgun. I
can repurpose equipment as needed in an emergency.

> have an established BGP session with our primary provider.
Do you have a private AS number or already a public one?

We have a public AS in place already.

> Can those of you doing this already tell me the optimum way to
> set this up? Is this best done on my end or by having my secondary

discover our

> disappearance and begin announcing?

I would say that it is better done on your end because it will
allow you to change your policy (see above my remarks). Also, it
is "the normal way" of operation for BGP.

Thanks for your input.

Hows it going, Travis?

A much more worthwhile read for a beginner, not that I mind slogging
through CCO, is Avi Freedman's intro to BGP at:
http://www.netaxs.com/~freedman/bgp/bgp.html

matto