default route via OSPF depending on the ISP

[Ondrej Zajicek]

On Thu, Dec 03, 2015 at 03:12:10PM +0000, Rohrmann Sascha wrote:
> > Well, you could use static default-route and 'check link' option, but that will help you only in the third case, not in the second one. 
> > For the second case, you must have some other way to establish whether ISP is up or down, either by running some routing protocol between 
> > you and ISP, or running BFD session.
> 
> Just as you said, that will only help me in the third case. 
> In which way should BFD be able to accomplish my goal?
> In my understandings BFD only checks if the link is available. If this isn't given, BFD tells Bird this problem.

BFD checks whether specified/destination IP is available (but it also must run BFD).
Therefore both link and host must be up.


> Second problem is, not every ISP supports BFD yet because BFD is kinda new. 

That is true, and also BFD-controlled static routes are only in devel version of BIRD,
not in v1.5.0


> I was thinking about a simple ping which checks the availability of the opposite party. 
> Am I able to include a simple shell script in bird? 

No


> Do you have more information and/or tips for me, by chance? 

As others wrote, you could do periodic pinging by e.g. fping and enable/disable a static protocol
using birdc (birdc disable XXX). See the attached script, which does something like that and 
estimating packet loss.


> > I was thinking about the bfd protocol, but bfd is kinda new and you can't run more than one instance in bird.
> > Well, is there any reason why to run multiple BFD instances in BIRD?
> 
> Well... you could create one bfd instance for one single interface.
> Furthermore you could then check the availability for e.g. my problem instead of checking all BFD instances.

I don't understand here.


-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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