In article <slrnbhul8b.91n.BitTwister@[EMAIL PROTECTED]
>,
Bit Twister <BitTwister@[EMAIL PROTECTED]
> wrote:
:On 24 Jul 2003 03:31:16 GMT, Walter Roberson wrote:
:> I suspect that what you really should be looking at is arranging
:> for ISP2 to -route- a single IP address when the link to ISP1 goes
:> down.
:I was wondering when we would get down to this point.
:When I enter the OP's url, my ISP (ISP0) would have to get an ip addy
:resolved to which ip address (isp1 or isp2)?
:When that isp is down, I still would hit 401.
In the BGP scenario, there would only -be- a single IP address, but
it would be an IP address which was not permanently assigned to
either ISP1 or ISP2 -- a "****table" address. ISP1 would -route-
the IP address to the OP over top of a carrier /29 or /30 that -is-
in ISP1's address space. ISP2 would also -route- the same IP
address to the OP overtop of a /29 or /30 part of ISP2's address space.
However, the routing priorities would be set up so that ISP2 would
surpress advertising the route to the outside world as long as
the ISP1 link was up.
Within a short time after the ISP1 link went down, ISP2 would
be notified to start advertising the route to the OP's public
IP address. The routing change would then propogate out to the
other networks, until eventually a router somewhere
downstream from your ISP0 that used to make the path decision
noticed the change and started using the new path.
I might have the details of which system does the advertising wrong.
I've never configured BGP, just read enough about it to know its
approximate function.
--
Oh, yeah, an African swallow maybe, but not a European swallow.
That's my point.
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