[nsp] Routing Problem: I am not sure where to begin.

[Jim Devane]

Jack,

1st and foremost, thank you very much for taking the time to reply.
2nd I will try your suggestion in a Thurs. night maintenance window.

I was wondering if you would indulge me a few more minutes of your time to
look the scenario over as it is a little different from what you outlined.

Actually, I have a little bit different of a setup. It is as below....(
stealing your ASCII diag) 

12012 (1.1.1.1/30) --W---  	       | ---W---\ (1.1.1.2/30)
		             |  SONET    |         7206
12012 (1.1.1.1/30) --P--		 | ---P---/ (1.1.1.2/30)

This is fine since the protect is "up/down" When the protect becomes active
it is using the same IP. 

CEF seems cool with it and the routing seems cool with it. 

WHY, oh why would I do this?

I don't want to tie the BGP session to just one router and I don't want more
than 1 BGP session.

Meaning, if I run BGP to the interface IP then BGP *should* never go down
when the interface changes. ( no BGP timer will go off and the new router
will send a open in time ) ((at least that is what I am hoping))

Ultimately, I want to be able to swap the customer between the routers
without taking a traffic hit ( upgrades or upstream trouble on one of the
GSR's I can switch over to other providers quickly )

Thanks again,

Jim


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
Jack.W.Parks at alltel.com
Sent: Monday, December 15, 2003 11:51 AM
To: cisco-nsp at puck.nether.net
Subject: RE: [nsp] Routing Problem: I am not sure where to begin.

If you are using /30 on the working and /30 on the protect then you have
two IP subnets that don't match when you have a fail over, because each
side fails independently.  Trying using a /29

For example:

Properly functioning APS setup (W) working and (P) protect. The /30's
match working-to-working (1.1.1.0/30) and one for protect-to-protect
(2.2.2.0/30)

           			 /-----------\
12012 (1.1.1.1/30) --W---  	       | ---W---\ (1.1.1.2/30)
		             |  SONET    |         7206
12012 (2.2.2.1/30) --P--		 | ---P---/ (2.2.2.2/30)
          			 \-----------/

In a failure, the scenario looks like:

           			 /-----------\
12012 (1.1.1.1/30) --W---  	       | ---P---\ (1.1.1.2/30)
		             |  SONET    |         7206
12012 (2.2.2.1/30) --P--		 | ---W---/ (2.2.2.2/30)
          			 \-----------/

Now the 1.1.1.1/30 connects to 2.2.2.2/30.  Use a /29 and the interfaces
(both working and protect) will share the same subnet and your routing
should work fine.

I hope this helps...

Jack


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Jim Devane
Sent: Monday, December 15, 2003 12:29 PM
To: cisco-nsp at puck.nether.net
Subject: [nsp] Routing Problem: I am not sure where to begin.


All,

 

I am having a routing problem that I don't know how to attack.

 

I have 2 12012's connect together by OC-48

Each 12012 in turn in connected by OC-3 to a Lucent DMX ADM. One OC-3 is
"working" and one is "protect"

Each of the OC-3's is connected downstream (through a SONET cloud) to a
customer and plugs into a 7206 VXR.

APS is configured on all the routers.

 

When I shut the "working" interface on one of the 12012's. The Protect
interface does go "up/up"  and a "sh controllers" show the correct SONET
info for the 7206. The 7206 does not see it's interface change and a "sh
controller" shows the new 12012 as being the downstream. 

 

I believe that APS/SONET is working correctly.

 

However, when this situation happens I am not able to pass L3 traffic.
No pings, no BGP, NUTHIN'.

 

I check the cef adjacency and the routes. The adj is correct and the
routes are not learned since BGP goes down.

Worse, I am not able to ping the directly connected far end interfaces.
Meaning, I shut the working on GSR 02, APS switches over to GSR 01 and
the protect becomes active.

 

If I do a sh ip route for the 7206 ip ( a /30 on the GSR) it will say it
is directly connected out the correct interface.

If I so a sh ip route for the 7206 on the former active GSR it says to
go to GSR 01.

 

Everything *looks* Ok, but traffic is not being passed.

 

Any ideas at all? I am not sure where to start?

 

TIA,

Jim

 

 

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