Routing

Hi All

I set a mpls enviroment with some routers. Looks like MPLS/LDP is established normallly.

But routes learning from iBGP are not pushed label.

Please refer to the sample configuration as the attachment.

Can give me some suggestion to troubleshoot it ?

Thanks 

Cloud

Attachment(s)

MPLS.rtf   2 KB 1 version

Are you running l3vpn (inet-vpn) or bgp LU?

Can you show your bgp config?

also, bgp assign labels to vpn routes when family "inet-vpn" is enabled. it doesn't assign the labels to internal routes

Hi Kingsman

Yes, I am running L3 VPN.

I think my problem is still on LDP on OSPF with FRR. It will cause adjaceny that can't push label , and indirect router will be fine.

Although I try to enable remote LFA to solve it, but it made my router's proccess crashing.

Now I need to figure out  another workaround.

Best regards,

Cloud  

Hello,

If routerA and routerB are directly connected, then by default the transport (LDP) label is 3 (implicit null).

If You want to see a label pushed, enable "protocols ldp explicit-null" - that would be label 0.

HTH

Thx

Alex

Hi 

Thanks for your relpy and I think  you got what I confused.

So, let say that direct connected router will display label 3 only by default ?

Thanks

Cloud 

Hi Cloud, 

the route which you are cheking is learned via BGP.

BGP doesn't advertise lable for internal routes unless you use BGP -LU family.

and yes, as Alex mentioned, Directly connected neighbor advertise (LDP) lable 3 (implicit nul) for local prefix ( loopback address) to each other 

Hello,

---

@Cloud wrote:

 

So, let say that direct connected router will display label 3 only by default ?

 

 

---

No, it will not "display" label 3. This label has a special meaning, it is never present in the packet and JUNOS does not show this label as being imposed/pushed.

By default, it will advertise via LDP:

1/ the FEC for own lo0.0 IP address(es) only

2/ the associated label 3 (implicit null") for the above

If You are not sure what FEC means please see RFC 5036 section 2

https://tools.ietf.org/html/rfc5036#page-8

HTH

Thx

Alex

Hi All

So, if two router is connecting directly, showing any bgp route from each other will not be shown label what push by LDP. 

Only bgp routes learnning from indirect adjaceny will be shown label.

Am I correct about this ?

Thanks

Cloud 

Hello,

You are correct - if

1/ You don't enable "protocol ldp explicit-null" knob

2/ don't use RSVP with "protocols mpls explicit-null" knob

HTH

Thx

Alex

Hi Folks,

Just thought of sharing this pointer on “How-To: Build a service provider network with a single Juniper Networks box--Part 1” to check control plane behavior in one box…

http://forums.juniper.net/t5/Routing/How-To-Build-a-service-provider-network-with-a-single-Juniper/ta-p/302237