BGP config WAS RE: [c-nsp] internet redundancy [7:99340]

[David Barak]

in-line

--- "Kern, Tom" <tkern at CHARMER.COM> wrote:

> 
> Ok, i'm still trying to set up an internet
> redundancy solution. 
> I unsucessfully attempted this only using eigrp and
> tunneling it through my firewall and redistributing
> static routes,etc. But that never worked.
> A while back someone mentioned bgp and to get over
> the FUD surrounding it and just try it.
> 
> Ok, so now i'm gonna try it.
> 
> My senario is probably well known(too well known,
> everyone on this list would say).
> I have 3 sites with 3 isps. The 3 sites connect to
> each other via point o point T1's(not the same
> routers as the internet facing one's).
> 
> I want to set up outgoing and incoming
> redudancy(disregard any resoultion issues and ddns
> soultions for now).
> 
> I'm going to use bgp.
> My question are as follows-
> 1.I need to use the ASN of each respective isp,
> correct? Do they charge for this normally?

you need to KNOW the ASN of all of your ISPs.  You
will need to get a public ASN from Arin (or whoever
your RIR is) - www.arin.net  Arin does charge an
annual fee for each ASN.


> 
> 2. Internally, do I need to run ibgp or should i
> redistribute ebgp into eigrp?

run iBGP - there are very, very few cases where
redistribution of ebgp into eigrp is good.  

> 
> 3. If i run ibgp, do i need a "real" ASN or can I
> use a private one?

You need a public ASN, but not because you're running
iBGP.

> 
> 4. Aside from setting up an AS-Path filter is there
> anything else i need to do to prevent filling up my
> routing table with isp routes?

Have your providers each advertise to you their own
routes and their customer's routes.  In addition, have
each provider send you a default route.  That way,
traffic to a given ISP (or that ISP's customers) will
take that ISPs links, but traffic to some other ISP
will take the closest path out.

> 
> 5. Am i missing anything else?
> 

Pick a consistent advertisement policy: originate only
aggregate routes of your largest aggregate.  Register
your ASN and your routes in the RADB (or another
registry)  (www.radb.net).  When running iBGP, don't
forget that you need a full mesh of all iBGP speaking
routers.  Use loopback addresses as BGP peering
addresses, and use the "next-hop-self" command.  Use
EIGRP under iBGP to carry the loopback addresses to
all of the BGP routers. 

Good luck!



David Barak
Need Geek Rock?  Try The Franchise: 
http://www.listentothefranchise.com

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