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CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 10:28 AM

Hej

I am experiencing ""CSPF failed: no route toward"" error in my RSVP lab. I have 8 routers connected in a Ring fashion R1-2-3-4-5-6-7-8-1. Running version 17.4R2.4 on MX104 with 8 logical systems.

 

I am running ISIS for IGP with all routers in Level 1

 

When I do not configure a specific path from R8-R3, then LSP establishes and goes from R8-R5-R4-R3 and shows up as UP.

Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 16777234)
172.30.0.37 S 172.30.0.29 S 172.30.0.21 S
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
172.30.0.37(Label=419) 172.30.0.29(Label=432) 172.30.0.21(Label=0)


However, when I configure a strict path for R8-R1-R2-R3, I get ""CSPF failed: no route toward"" error message. But in the routing table I can see R3 Loopback can indeed be reached from R1 onwards.

 

Even if I configure no-cspf under the LSP, the LSP appears with __show rsvp session__ but stays in down state. Without no-cspf the LSP doesn't even appear with __>show rsvp session__ command.

{master}[edit protocols mpls]
odj@test3pe1dkSmiley Surprisedscar-Lab-R8# run show mpls lsp name I extensive
Ingress LSP: 2 sessions

172.30.5.3
From: 0.0.0.0, State: Dn, ActiveRoute: 0, LSPname: I
ActivePath: (none)
LSPtype: Static Configured, Penultimate hop popping
LoadBalance: Random
Encoding type: Packet, Switching type: Packet, GPID: IPv4
LSP Self-ping Status : Enabled
Primary I-primary State: Dn
Priorities: 7 0
SmartOptimizeTimer: 180
Flap Count: 1
MBB Count: 0
Will be enqueued for recomputation in 18 second(s).
18 Nov 3 18:55:02.642 CSPF failed: no route toward 172.30.5.1[19 times]
17 Nov 3 18:27:18.064 Deselected as active
16 Nov 3 18:27:18.051 CSPF failed: no route toward 172.30.5.1
15 Nov 3 18:27:18.041 Clear Call
14 Nov 3 18:21:54.392 Self-ping ended successfully
13 Nov 3 18:21:53.437 Selected as active path

7 REPLIES 7
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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 10:31 AM

Here are the CSPF traceoptions

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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 11:37 AM

Hi Oscar,

 

can you can confirm the R8-R1 links are enabled under the protocols MPLS/RSVP stanza? 

The "link is one-way" in the traceoptions output would suggest one of the sides is not enabled under RSVP/MPLS.

 

Nov  3 19:21:44.005632       Link 172.30.0.10->172.30.0.9(test3pe1dk-Oscar-Lab-R1.00/172.30.5.1, Link IDs 541->381) metric 10 color 0x00000002 bw 333Mbps
Nov  3 19:21:44.005666  Reverse Link for 172.30.0.10(172.30.5.8:541)->172.30.0.9(172.30.5.1:381) not found
Nov  3 19:21:44.005746  link is one-way

Cheers,

Radek

 

 

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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 01:55 PM

If the LSP does not come up even with no-cspf, and with the routing protocol working along the path as you indicate, there is probably an interface that is not configured with RSVP or MPLS.  

 

Regards,

Yasmin Lara - Juniper Ambassador #QuadE - JNCIE-SP, JNCIE-ENT, JNCIE-DC, JNCIE-SEC
JNCIS-CLOUD, JNCDS-DC, JNCIA-DevOps
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Re: CSPF failed: no route toward -- RSVP session error.

[ Edited ]
‎11-03-2019 02:25 PM

Hej

The interfaces are configured for RSVP and MPLS. I actually do have a seperate RSVP LSP between R1 and R8 which is up and running. There are also individual LSPs between R1-R2 and R2-R3 as well.

Currently on the path I configured all routers are configured as Strict. If I change R1 to loose, then the CSPF error starts to say Next-hop-unreachable 172.30.5.2 which is the R2. 

 

Regards

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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 02:40 PM

Can you share the config? 

Yasmin Lara - Juniper Ambassador #QuadE - JNCIE-SP, JNCIE-ENT, JNCIE-DC, JNCIE-SEC
JNCIS-CLOUD, JNCDS-DC, JNCIA-DevOps
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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 02:57 PM

Hej

After your suggestions I got a bit more paranoid and checked all the config and interfaces. There was actually a problem with physical link between R1-R8.
The LSP between R1-R8 was not single hop as it should have been, but was 3 hops insteads. I guess I shouldn't have taken the existence of LSP as granted.
Once the physical link was fixed, the LSP with strict routes constraints came up properly.

 

Thanks for the advices, kudos given
Oscar

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Re: CSPF failed: no route toward -- RSVP session error.

‎11-03-2019 03:35 PM

I am glad! Smiley Happy

I was wondering if you were poiting to a loopback and that was why loose worked but not strict. 

Yasmin Lara - Juniper Ambassador #QuadE - JNCIE-SP, JNCIE-ENT, JNCIE-DC, JNCIE-SEC
JNCIS-CLOUD, JNCDS-DC, JNCIA-DevOps