nanog mailing list archives

Re: wet-behind-the-ears whippersnapper seeking advice on building a nationwide network


From: Jon Lewis <jlewis () lewis org>
Date: Tue, 20 Sep 2011 08:01:46 -0400 (EDT)

On Mon, 19 Sep 2011, Matthew Kaufman wrote:

On 9/19/2011 6:02 PM, Jon Lewis wrote:
On Sun, 18 Sep 2011, Frank Bulk wrote:

I should have made myself more clear -- the policy amendment would make
clear that multihoming requires only one facilities-based connection and
that the other connections could be fulfilled via tunnels.  This may be
heresy for some.

That's not multihoming.

Really? Lets try these and see how you do:

The ARIN NRPM actually defines it:

 2.7. Multihomed

 An organization is multihomed if it receives full-time connectivity from
 more than one ISP and has one or more routing prefixes announced by at
 least two of its upstream ISPs.

IMO, "full-time connectivity" would mean a leased line, ethernet, or even wireless connection, but not a GRE or other tunnel (which is entirely dependent on other connectivity).

i.e. if you have a leased line connection to ISP-A, and a tunnel over that connection to ISP-B, and either A or your leased line fail, then you're down. That's not multihoming.

Some of the scenarios you suggested are pretty unusual and would have to be considered on a case by case basis. i.e. a shared T1 to some common point over which you peer with 2 providers? I'd argue in that case, whoever provides or terminates the T1 in that case is your one transit provider, and again, you're really not multihomed...unless its your T1 and your router at the remote side, and that router has ethernet to the two providers...then that router is multihomed, and though most of your network is not, I'd argue that you have satisfied the requirement for being multihomed.

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 Jon Lewis, MCP :)           |  I route
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