[c-nsp] BFD w/ static routes

[Gert Doering]

Hi,

On Thu, Aug 04, 2005 at 05:08:00PM +0300, Pekka Savola wrote:
> The ISPs PE routers run iBGP or an IGP between each other.  The 
> customer is routed with static routing.  When the primary link goes 
> down, due to media converters or whatever, the PE and customer router 
> may still think the link is up.  The customer's prefix is still routed 
> towards the failed link (and the same for customer's default route 
> pointing to the ISP) and traffic is blackholed.

Full ACK.  Similar setup here - customers reachable via ethernet briding
devices that do not properly set link-down when there's something broken
in between.

> This problem is typically solved by running BGP or an IGP to detect 
> link failures and reroute.  We don't want to run an IGP across an 
> admin domain, and setting up and maintaining BGP is too complex for 
> the customer.

ACK again.

[..]
> Hope this clarifies.  If there are other ways to solve this problem 
> (apart from using routing protocols or BFD), pointers are welcome..

object tracking via "ping" works, but is ugly.  BFD is much more elegant
("designed for that job").

I wonder whether BFD is already available in entry-level boxes (2600,
831, etc.)?

gert
-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de