configurable for BFD tied to LDP? (IOS-XR 7.3.2)

[Ktry]

Hi,

I have NCS, version 7.3.2.

I would like to configure an interface BFD tied to LDP. Currently, OSPF is used as the IGP, but I want to inform LDP before OSPF, so I'm looking to configure an interface BFD tied to LDP.

However, it seems that I can't. Is there hardly any chance to implement it?

RP/0/RP0/CPU0:183(config-ldp)#interface bundle-ether 790 address-family ipv4 ?
discovery Configure discovery parameters
igp Configure igp parameters
mldp Configure mLDP parameters
<cr>


And client is ospf (maybe that's default. I assume tieing with LDP is not doable..)

RP/0/RP0/CPU0:183(config-ldp)#do sh bfd ipv4 session interface bundle-ether 790 detail
Thu Jun 6 22:48:43.181 JST
I/f: Bundle-Ether790, Location: 0/RP0/CPU0
Dest: 10.9.201.238
Src: 10.9.201.237
State: DOWN for 0d:1h:11m:33s, number of times UP: 0
(snip)
Session owner information:
Desired Adjusted
Client Interval Multiplier Interval Multiplier
-------------------- --------------------- ---------------------
ospf-100 150 ms 3 150 ms 3

Regards,

[MHM Cisco World]

BGP tied to LDP ?

I dont full understand your request 
but 

there is IGP - LDP Sync that make IGP delay until LDP is form 
you can tune this Sync if you face some drop in packet due of missing label

MHM

[Ktry]

Hi,

No, I meant BFD tied to LDP, not BGP. Essentially, in scenarios like a link failure or protocol error, I want LDP to be informed more quickly than IGP. Therefore, I'm specifically looking to implement BFD tied to LDP intentionally.
Regards, 

[Reza Sharifi]

Hi,

I'm not sure if that is an option, as BFD works with the routing protocol. Have a look at this post.

https://community.cisco.com/t5/mpls/bfd-with-ldp/td-p/2264164

HTH

[Ktry]

Thanks, yeah, BFD can be tied to routing protocols.
In this case, I'd like to tie it to LDP... The reason of it arises from LDP wants to be informed quicker than IGP when errorneous situation occurs.
Regards,

[Ktry]

> LDP is not supported as a client of BFD, its the routing protocols that become clients.
I read it, I see...
If this applied to this box, I will think another idea.

[Reza Sharifi]

Usually, you deploy BFD for BGP, as BGP converges very slowly compared to other protocols like OSPF.

Once you deploy BFD, the failover time goes from minutes to a few seconds, which is very fast. We use it for BGP failover, and it works really well.

HTH 

[Harold Ritter · Accepted solution]

Hi @Ktry ,

The path the traffic takes through your network is determined by the IGP. LDP only provides label mapping to the next hop. BFD is tied to the IGP, not to LDP. If you want to make sure the IGP and LDP are in sync, you can use the LDP IGP synchronization feature.

Regards,

[Ktry]

Thank you very much, Harold. Yes, I understand your suggestion. However, I might not be seeking the typical functionality of LDP-IGP synchronization in this scenario.
Currently, BFD has been implemented with BoB (RFC 7130), and it is not configured under IGP. When an erroneous situation occurs, BoB notifies the upper layers, such as OSPF/LDP. Although BoB is also configured on the 3rd vendor box , there appears to be a slight delay in the notification speed from the bundle-ether level to the upper layer protocols across different devices, which might be contributing to the issue I'm facing. To address this, I am considering enabling BFD at the OSPF level to mitigate the timing discrepancies. Regards,

[MHM Cisco World]

I dont forget your case 

I see other vendors use bfd with ldp but for cisco I need two more days to check

MHM

[Ktry]

Thanks, MHM. Really appreciated. I'm using NCS 7.3.2 but seems I can't configure BFD under LDP.
Anyway, I wait for that.