MPLS freezes Winbox Access

RouterOS Forwarding Protocols
1

Hi,

I’m trying to deploy MPLS in a lab to study VPLS and TE Tunnels.

This is my scenario (R1 to R7 are RB493AH):

My notebook is connected to R1, and the server to R4.
All routers are in 6.37.5 version. Also, all of them have loopback configured (10.0.0.1 to 10.0.0.7)
OSPF is running perfectly. All paths have cost = 10.

The problem is: when I enable MPLS in all routers, some routers became freezed (R3, R4, R6 and R7) when I try to access them from the notebook.
Example: R3 with MPLS enabled:

I’ve enabled LDP settings, configured LSR ID and transport address equal to IP of loopback.
All routers have default MTU = 1508.

What I am doing wrong?
Any suggestions?

2

Hello

first upgrade to version 6.38.5
than filter ldp and only announce loopback address
ensure that MPLS is active in ospf instance

a+
Thierry

3

It is an MTU issue, tunnels in your setup cannot pass 1500byte packets.

4

At the moment, I only have OSPF and MPLS enabled.

From the notebook, winbox have full access to R1, R2 and R5.

Routers R3, R4, R6 and R7 reply ping perfectly, but show blank boxes inside Winbox.

Which MPLS MTU do you suggest to use?

I’ll try to upgrade to 6.38.5, like Thierry said, to try solve this issue.

:slight_smile:

5

Updating:

I’ve done the following steps in all the RB493AH:

  • updated to 6.38.5;
  • resetted to default, with no-default=yes;
  • reconfigured OSPF with loopbacks;
  • enabled MPLS (LDP-settings = enabled | interfaces ether2 and ether3 added to LDP interfaces).

But… still same issue: R1, R2 and R5 are available through winbox.
Other routers (R3, R4, R6 and R7) shows blank boxes inside winbox.

As soon as I disable MPLS, all routers became fully available. :frowning:

Then, I’ve created a VPLS tunnel between R1 and R4:

  • Notebook and Server were able to communicate;
  • R4 became available through the MAC address of VPLS tunnel;
  • R4 still shows blank boxes through MPLS cloud (winbox access to 10.0.0.4).
6

Hi all
I have the same problem.
what mtu must I use?
thank you

7

I’ve changed all routers to RB2011.

I’ve tried MPLS MTU = 1598 in all routers

I’ve removed R5, R6 and R7 from scenario, but the issue still persists: R3 and R4 show blank boxes inside winbox.

Is this a normal behavior from a PC connected in a interface that doesn’t speak MPLS?

Which is the correct way to manage this MPLS cloud?

:confused:

8

It seems that is working now. I added R5, R6 and R7 again.

I’ve changed all seven routers of lab to MPLS MTU = 1522.

Now winbox is loading, before creating TE tunnels.
And traffic is going through the TE tunnels, after create them in R1 and R4.

I don’t know why it didn’t work with 1508 bytes of MPLS MTU.
1504 bytes must be enough to carry 1500 bytes of L3 + 4 bytes of one label :confused:

The questions are:

  • Does the MPLS use one or two labels to make the MPLS cloud? :confused:
  • If I want to create VPLS, will MPLS MTU of 1522 be enough —> 14 + 4 + 4 + 1500 (14 bytes of L2 + 4 bytes of VPLS label + 4 bytes of MPLS + 1500 bytes of L3)? :confused: