On Tue, Sep 20, 2011 at 5:19 PM, Brett Frankenberger <rbf+nanog@panix.com>wrote:
On Tue, Sep 20, 2011 at 04:13:57PM -0400, Dorn Hetzel wrote:
"full time connection to two or more providers" should be satisfied when
network involved has (or has contracted for and will have) two or more connections that are diverse from each other at ANY point in their path between the end network location or locations and the far end BGP peers, whether or not the two or more connections are exposed to one or more common points of failure, as long as their are any failure modes for which one connection can provide protection against that failure mode somewhere in
the the
other connection.
The GRE tunnel configuration being discussed in this thread passes this test. Consider the following: ISP #1 has transit connections to upstream A and B. ISP #2 has transit connections to upstream C and D ISP 1 and ISP 2 peer.
Customer gets a connection to ISP #1 and runs BGP, and, over that connection, establishes a GRE tunnel to ISP #2, and runs BGP over that also.
I assume your last clause requires that each connection provide protection against a failure more in the other connection (not just that one of the two provide protection against a failure mode on the other). This is satisfied. In my example:
ISP #1 provides protection against ISP #2 having a complete meltdown.
ISP #2 provides protection against ISP #1 losing both its upstream connections.
-- Brett
Yes, that is what I was trying to say, that there are at least k providers, k>=2, and that at least 2 of those k providers offer at least some redundancy for some possible failure modes in the other provider. Your example is especially plausible if it happens that the router from which ISP #1 provides me service is the same router, or at least close in the same POP, to the router from which they peer with ISP#2. ISP#1 might then have a complete backbone meltdown, but retain their local peering session with ISP#2, which would allow me to still reach my tunnel endpoint in ISP#2 and the BGP session resulting. -Dorn