[c-nsp] Multihoming

[Tim Huffman]

>Another option might be to get a small amount of space from each provider, 
>and VPN into something more stable/better connected.

Something I've been considering is to have the customer build a GRE tunnel (its Internet traffic anyway) back to our router over their other ISP's connection. We could then route their public IP space over either connection.

It doesn't give all the same benefits of BGP (for example, if something happens to my AS or router, the customer is screwed), but it should make for cheap and easy multihoming.

Anybody have any thoughts on this?

Tim Huffman
Director of Engineering
BOB - Business Only Broadband, LLC
O (630) 590-6012
C (630) 340-1925
tim at bobbroadband.com
www.bobbroadband.com



-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Jon Lewis
Sent: Wednesday, September 15, 2010 10:15 AM
To: Walter Keen
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Multihoming

On Wed, 15 Sep 2010, Walter Keen wrote:

> Not many options for you I'm afraid.  Some people filter out routes smaller 
> than a /24.  Even if you had a /24 from ISP1, you would then have to get 
> their permission to have ISP2 advertise it.  Most aren't willing to do this.

Huh?  Get a /24 from one of the ISPs.  Get an ASN from ARIN or whoever is 
the appropriate registry for your area.  Advertise (BGP) that /24 to both 
ISPs.  I've never heard of an ISP not allowing this (except that most 
probably won't do BGP with you if you're on a "low end" connection like 
DSL/cable.  If you have some sort of leased line or ethernet connectivity 
to each provider, it shouldn't be an issue.

> Is a micro (/24) allocation from ARIN (if in the US) a possibility?  If so, 
> you could then run BGP to multiple providers and make this a very simple 
> configuration.  If not, you'll likely have to rely on application-layer 
> redundancy.  You can prioritize MX records if you are hosting your mail 
> on-site through ISP1's ip addressing (what you stated seemed a bit unclear), 
> and you could probably do some round-robin DNS entries for web hosting, but 
> it won't be perfect.

Another option might be to get a small amount of space from each provider, 
and VPN into something more stable/better connected.

----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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