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

Jon Lewis jlewis at lewis.org
Tue Sep 20 12:01:46 UTC 2011

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.

  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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