I run lab and it work
change the subnet between B and C and check again
the OSPF and MPLS not accept subnet 17216.0.0/31 <<- this need to be 30 and dont use .0 this network ID not host IP
Hi Harold,
Router A is an ASR9k running 7.3.2, Router P is a NCS 5508 running 7.3.2 as well. Router B is another 9k running 7.9.21.
The CEF output shows that something might not be right. I configured both static routes towards router C, one with next hop 172.16.0.235, the other with 172.16.0.50. Router A installs both in its routing table:
S 3.3.3.3/32 [1/0] via 172.16.0.235, 00:22:15
[1/0] via 172.16.55.50, 00:22:15
Looking at the cef however:
show cef 30.235.9.117/32 detail
Sat Feb 17 09:22:36.058 CET
30.235.9.117/32, version 493326, internal 0x1000001 0x30 (ptr 0x7904f380) [1], 0x0 (0x7900aef8), 0xa00 (0x8970c0a8)
Updated Feb 17 09:03:43.819
Prefix Len 32, traffic index 0, precedence n/a, priority 3
gateway array (0x78e75408) reference count 2, flags 0x8078, source lsd (5), 1 backups
[3 type 4 flags 0x108441 (0x794f9e40) ext 0x0 (0x0)]
LW-LDI[type=1, refc=1, ptr=0x7900aef8, sh-ldi=0x794f9e40]
gateway array update type-time 1 Feb 17 09:03:43.820
LDI Update time Feb 17 09:03:43.826
LW-LDI-TS Feb 17 09:03:43.826
via 172.16.0.235/32, 3 dependencies, recursive [flags 0x0]
path-idx 0 NHID 0x0 [0x7904ee08 0x0]
next hop 172.16.0.235/32 via 172.16.0.235/32
local label 24002
next hop 172.16.6.24/32 Hu0/0/0/1 labels imposed {28115 None}
via 172.16.55.50/32, 3 dependencies, recursive [flags 0x0]
path-idx 1 NHID 0x0 [0x7904e188 0x0]
next hop 172.16.55.50/32 via 172.16.55.50/31
local label 24002
next hop 172.16.6.24/32 Hu0/0/0/1 labels imposed {None} <<< no label when next hop is 172.16.55.50
Load distribution: 0 1 (refcount 3)
Hash OK Interface Address
0 Y recursive 172.16.0.235
1 Y recursive 172.16.55.50
It looks like A is not receiving a label to forward traffic to 172.16.55.50.
Router P has no entry for 3.3.3.3 in its cef but looking at the ldp bindings:
RP/0/RP0/CPU0:NCS-01#show mpls ldp binding 3.3.3.3/32
Sat Feb 17 09:36:08.775 CET
3.3.3.3/32, rev 0
No local binding
Remote bindings: (2 peers)
Peer Label
----------------- ---------
172.16.0.48:0 24002
172.16.0.235:0 24024
RP/0/RP0/CPU0:NCS-01#show mpls ldp binding 172.16.55.50/32
Sat Feb 17 09:36:23.919 CET
RP/0/RP0/CPU0:NCS-01#show mpls ldp binding 172.16.0.235/32
Sat Feb 17 09:36:32.767 CET
172.16.0.235/32, rev 256
Local binding: label: 28115
Remote bindings: (7 peers)
Peer Label
----------------- ---------
172.16.128.5:0 24004
172.16.0.43:0 65
172.16.0.47:0 133
172.16.0.48:0 24123
192.168.0.140:0 54
192.168.0.141:0 24119
172.16.0.235:0 ImpNull
It looks that Router B is not passing to P a label for 172.16.55.50/31.
So if I am getting these outputs right: There's no LSP from A to 172.16.55.50.
Ping towards 172.16.55.50 from A works solely because since the network is known in OSPF to P it can route the packet using the ip header infos even if the LSP is broken. However since no mpls encapsulation is happening when trying to ping 3.3.3.3 router P not having this network in its routing table and not being able to use the mpls header for routing since there's none, drops the packet.
Is this correct?
I've made a topology of the scenario to better help understand the outputs:
I dont like use /31 but since you need to use it I run lab again and also it work
in router 3 I add 120.0.0.0 0.0.0.1 area 0 under the ospf, this make R3 advertise the prefix with it label to both R2 and R1
R1 will use ip route 4.4.4.4/32 120.0.0.0
R1 know the prefix 120.0.0.0 and it label
so first step in your case is check
are router R1 (R-A) use static route toward R3 IP not R4 IP ?
are R1 know this subnet between R3-R4 via OSPF and add it to MPLS table ?
