Community discussions

MikroTik App
 
Robinco
just joined
Topic Author
Posts: 12
Joined: Tue Apr 22, 2014 11:00 pm

MPLS/LDP neighbors blinking in/out

Sat May 10, 2014 8:19 pm

Is it normal for MPLS/LDP neighbors to be listed but blinking on an and off every few seconds?

5 2011 routers v6.2 ospf, seems to be working ok. loopbacks are configed as 10.0.0.1 - 10.0.0.5, and these are entered as LDP LSR ID and transport ID on each respective router. MPSL MPU on each router are set to 1560. Nothing comes up when I print local or remote bindings.

The entries of ldp neighbors on a couple of units blink in and out every 5 seconds so so. Is this normal since they are dynamic or should this be stable when neighbors are established?
 
User avatar
tomaskir
Trainer
Trainer
Posts: 1122
Joined: Sat Sep 24, 2011 2:32 pm
Location: Slovakia

Re: MPLS/LDP neighbors blinking in/out

Sat May 10, 2014 8:49 pm

Not normal, it seems like an LDP neighborship is trying to establish but is failing / timing out.
Unimus - configuration management, automation and backup solution
Mass Config Push, network-wide RouterOS upgrades, and more!
 
Robinco
just joined
Topic Author
Posts: 12
Joined: Tue Apr 22, 2014 11:00 pm

Re: MPLS/LDP neighbors blinking in/out

Sat May 10, 2014 9:59 pm

Thanks you.
Do I need to set any router interface MTU to 1560 or just the MPLS MTU.?

Also under OSPF do I change Redistribute default route & connected routes & static routes to "as type 1" on all of the routers or just one main one?

Thanks very much again.
 
User avatar
tomaskir
Trainer
Trainer
Posts: 1122
Joined: Sat Sep 24, 2011 2:32 pm
Location: Slovakia

Re: MPLS/LDP neighbors blinking in/out

Sun May 11, 2014 12:19 am

Thanks you.
Do I need to set any router interface MTU to 1560 or just the MPLS MTU.?

Also under OSPF do I change Redistribute default route & connected routes & static routes to "as type 1" on all of the routers or just one main one?

Thanks very much again.
You need to configure all the L3, L2 MTUs, MPLS MTUs, etc.
See this vid for MPLS overview: http://tiktube.com/video/KHhE3aEKdDoDEJ ... sDlIoFqoq=

As for OSPF, set redistribution on all routers.
Unimus - configuration management, automation and backup solution
Mass Config Push, network-wide RouterOS upgrades, and more!
 
Robinco
just joined
Topic Author
Posts: 12
Joined: Tue Apr 22, 2014 11:00 pm

Re: MPLS/LDP neighbors blinking in/out

Sun May 11, 2014 1:11 am

Yes I have watched that video a couple of times and just didn't understand some of these details.

Thank you
 
Robinco
just joined
Topic Author
Posts: 12
Joined: Tue Apr 22, 2014 11:00 pm

Re: MPLS/LDP neighbors blinking in/out

Sun May 11, 2014 7:53 pm

Figured it out. Hopefully this will help some others.

In all the video's and reading of examples I had done, a few things were not clear to me.

1) How to set up the loopback properly. I had the loopback on each router set to /24 and they need to be set as /32 with the network set as the same IP/32. For instance, my routers have loopback addresses of 10.0.0.1 - 10.0.0.18. I had each loopback address set as 10.0.0.x/24 with the network set as 10.0.0.0. I needed simply set the loopback address as 10.0.0.x/32 and the network also set the same at 10.0.0.x.

2) I need a larger MTU of 1560 for MPLS, but in most of the examples I viewed/read, they only showed changing the MPLS interface to 1560. I'm not sure if it is needed but I changed every physical interface to MTU of 1560 also. Note: On some of the routers, the L2 MTU's were 1520 and it wouldn't let me change the MTU to 1560 (couldn't be larger than L2MTU). On the other routers, the L2MTU was defaulted at 1598.) I changed all of the routers with L2MTU of 1520 to 1598 and I could then change the MTU to 1560.

3) One router in the mix was a 450GL. Didn't realize that it won't support an MTU of more than 1520? Replaced it with a 750GL and made the correct L2MTU and MTU settings.

4) I didn't have the loopback addresses included in OSPF. I finally caught this on a slide show I found (it was barely mentioned). On each of the routers I added the loopback IP address of 10.0.0.x to OSPF. After I did this, the local & remote bindings came up, the LDP neighbors stopped blinking and MPLS started working.

I'm not positive I needed to change every physical interface on all routers to MTU of 1560 but it seems to be working.

Most of this is probably obvious to the experienced people but it is first time setting up OSPF and MPLS for me. If anything in the list needs to be corrected, please say so and I will correct. Otherwise, I hope it can help somebody.

rk
 
adairw
Frequent Visitor
Frequent Visitor
Posts: 60
Joined: Sun Jan 29, 2012 6:32 pm

Re: MPLS/LDP neighbors blinking in/out

Sun May 11, 2014 8:21 pm

Hi Robert, responded to your email but it sounds like you've got this worked out for now.

Just got the benefit of the forum. To use mpls with vpls you have to use a router that has an l2mtu of greater than 1526. So the 450g is out. Mikrotik has a page shower the various mtu's of all the models of routers.

Who is online

Users browsing this forum: No registered users and 7 guests