[c-nsp] forced path MPLS tunnel question

[Arie Vayner (avayner)]

Gert,

Maybe another approach could be to use the IP SLA LSP ping option...
Seems to be supported since SXH:
http://www.cisco.com/en/US/docs/ios-xml/ios/ipsla/command/sla_s2.html#GU
ID-91306735-FA32-4AF8-B8EF-61FD667CD15B


Arie

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Gert Doering
Sent: Tuesday, January 17, 2012 12:05
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] forced path MPLS tunnel question

Hi,

I'm currently considering options to better monitor the MPLS bits of our
network - specifically, make sure that MPLS *forwarding* works, without
having to rely on end systems noticing EoMPLS links going "black hole"
or L3 VRFs going down.

One of the reasons for MPLS forwarding to break could be "ethernet
circuit bought from $3rd_party, their equipment failing to properly
forward all different ethernet types -> IPv4 works, MPLS fails" -
happened to a colleague recently, which got me thinking...

The way I thought this could be done is to setup a MPLS tunnel with a
static path, crossing all "major" links (this is a small network, so the
tunnel just needs to go through 6 routers or so to visit all backbone
MPLS links), and then send ping probes down that tunnel.  MPLS
forwarding breaks -> ping breaks -> operator goes investigating.

Now, the documentation that I found ties this to 

  "tunnel mode mpls traffic-eng"

and *this* seems to require OSPF or ISIS being used as an IGP - which we
don't have, right now.

(Platform is 6500/Sup720, IOS 12.2SXH/SXI)


So, Question #1:

 - is there a way to setup a static MPLS tunnel/LSP "take *this* link
and
   then *that* link and then go *there*" without OSPF or ISIS?

Question #2:

 - what is happening "behind the scenes" to make static(!) paths require
   OSPF / ISIS?  I can understand that auto-te needs the necessary
metrics,
   but "basic MPLS" works fine with just BGP/LDP/EIGRP...

(And yes, I could move everything over to OSPF, it's just that I want to
understand the reasons for it)

thanks,

gert
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Gert Doering - Munich, Germany
gert at greenie.muc.de
fax: +49-89-35655025
gert at net.informatik.tu-muenchen.de