Re: [mpls-linux-general] Mpls installation problems with the new version.

[Oliver H. <ho...@tm...>]

Am Mit, 2002-07-31 um 18.21 schrieb James R. Leu:
> On Wed, Jul 31, 2002 at 05:07:04PM +0200, Oliver Horvath wrote:
> > Am Mit, 2002-07-31 um 17.53 schrieb James R. Leu:
> > > http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/mpls-linux/mpls-linux/NOTE?rev=1.5.2.2&only_with_tag=mpls-linux_1_152&content-type=text/vnd.viewcvs-markup
> > ok. That means, that MPLS is working well? Nice! :]
> > But why I am not able to let a traceroute running?
> > Ping works well, but traceroute has not output? (see mailing below)
> 
> Handling of packets with TTL <= 1 is broken right now.  The result is that the
> packet gets dropped.  I think I know how I'm going to handle it:
> 
> Check if this is the botton of the stack, if not drop the packet.
> Check the protocol associated with the ILM, if it is not IP, drop it.
> If it is IP, generate an ICMP message, and forward it along the LSP, the
> egress can deal with the ICMP message.
> 
> There is probably a special case where it is the egress of the LSP that
> finds a TTL <= 1 that needs to be handled differntly.  Besides that,
> does this sound like the right behavior?

Sounds good for me.

I tested ethereal in the middle of a lsp (no edge router) and there it
works well.
Do you have a idea, if there is a chance to monitor the edge routers
correctly too?
I defined a wrong outgoing lable on a edge router, and I saw two things:
a) Ping is still working, but why? If mpls didn't know the incoming
label, it pops the label off and tries to find a working label in the
outgoing labels? Or is the label poped off and forwarded by normal ip?
b) Tracerout stops at the middle of the lsp (3 PCs). Why it is not
forwarded like the pings?

Oliver