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Visitor
Judy
Posts: 3
Registered: ‎04-13-2012
0

LDP looping protection

Hi,

 

We have LDP looping in network. Can somebody help me to understand how Juniper implemented LDP looping prevention and detection of MX Routers? What configuration I need?

 

Thanks,

 

Judy

Contributor
abhilash.rajappan
Posts: 31
Registered: ‎10-14-2010
0

Re: LDP looping protection

 

Hope the attached PDF helps:

 

Regards,

Abhilash

Contributor
krenjt
Posts: 78
Registered: ‎11-12-2010
0

Re: LDP looping protection

Hi

 

  What i know is that LDP itself does not have a loop prevention mechanism, it sets up a LSP based on IGP shortest path, so it depends on IGP to provide loop prevention mechanism.

 

Hope that will help you.

 

 

ThankS!

Visitor
Judy
Posts: 3
Registered: ‎04-13-2012
0

Re: LDP looping protection

Thanks for your replay!

 

I have enabled LFA(IP FRR) in our network.  That is why we have two best routes but LDP and IGP have different routes.

 

I expected IGP route is selected instead of LDP route. 

 

x.x.x.x./32    *[LDP/9] 00:29:38, metric 681

                    > to x.x.x.101 via ae2.0, Push 700000 ------------->Do not know why LDP pick up ae2. 0

                    [OSPF/10] 18:41:04, metric 681

                    > to x.x.x.121 via ae1.0 --------------------> this one should be selected

                      to x.x.x.101 via ae2.0

 

 

Judy

Contributor
jackycheung
Posts: 52
Registered: ‎02-02-2010
0

Re: LDP looping protection

Visitor
Judy
Posts: 3
Registered: ‎04-13-2012
0

Re: LDP looping protection

You are right that LDP has high preference. In our case, LFA is enabled. If LDP and OSPF does not sync correctly, it casues a loop. That is what is happening here. Any clue?

 

Regular Visitor
jasonlai
Posts: 7
Registered: ‎08-09-2010
0

Re: LDP looping protection

Hi,

 

Have you configure LDP synchronization ?

 

user@host# show protocols ospf 
area 0.0.0.0 {
            interface so-1/0/3.0 {
                ldp-synchronization {
                      hold-time 10;
                }
            } 
}

 

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