MPLS LDP Filter

[gmachado11]

Hello,

I have a little bit odd situation.

I am planning on connecting two devices using MPLS over my backbone. One is a CISCO7600 and the other is a CAT6500 both are running IOS.

C7600 is running: c7600s72033-advipservicesk9-mz.122-33.SRD4.bin /  WS-SUP720 MSFC3

C6500 is running: s72033-advipservicesk9-mz.151-2.SY1.bin / SUP720-10GE with MSFC3

The configuration for filtering the prefixes to exchange LDP is below:

!
mpls ldp label
 allocate global prefix-list LOOPBACKS
!

!
ip prefix-list LOOPBACKS seq 5 permit 10.11.255.0/24 ge 32
ip prefix-list LOOPBACKS seq 10 permit 10.12.255.0/24 ge 32
!

Why it works on C7600 but not on the C6500? Should I use the command: "allocate global host-routes" ?

Thank you.

Gil

[Vasilii Mikhailovskii]

Hello.

Could you please provide more information (per box and on first LDP neighbors):

 - loopback's IP-addresses per box;
 - show mpls ldp bin <remote loopback>
 - show mpls ldp bin <unexpected prefix>
 - show mpls for <unexpected prefix>

PS: did you try to restart your MPLS LDP as a part of troubleshooting?

[gmachado11]

Hello

Here it is a sample config used in the LAB that actually worked for the combination IOS 15.1(2)SY1 (advanced IP services) and the Switch 6509.

1) Configure the ACL with the IPs you want to have allowed for communication using LDP.

ip access-list standard PE_LOOPBACKS
 permit 10.10.20.40
 permit 10.10.20.41
 permit 10.12.20.12
 permit 10.12.20.13
!

2) Configure the normal MPLS

mpls label protocol ldp

3) Make sure you remove the advertised labels

mpls label protocol ldp

4) make sure you advertise labels only to the IPs you have in the ACL.

 mpls ldp advertise-labels for PE_LOOPBACKS

5) Make sure you force the loopback to advertise the labels:

 mpls ldp router-id loopback 0 force

6) Use the trace command to validate the Labels are assigned properly.

That is it. Please let me know your results.

Thanks

[bhnegi]

Unfortunately local label allocation filtering is not supported on the 6500, there is no available way to filter the local label allocation on the 65K as on 7600.

http://www.cisco.com/c/en/us/td/docs/ios/mpls/command/reference/mp_m2.html#wp1029906

12.2(33)SRC

This command was introduced.

12.2(33)SB

This command was integrated into Cisco IOS Release 12.2(33)SB.

Best Regards,

Bheem