Lab 3 - LDP not coming up

HI everybody, 

ia m redoing Lab 3 but i found a strange issue at point 4.6 . So, just to say, everything works absolutely fine up to 4.5 and BGP is well happy to communicate with anybody. The task 4.6 is asking essentially to implement label-switching for CSC purposes. Between XR2 and R6  this is the config:

IOS XR

router ospf 1

 area 0

  mpls ldp auto-config

  interface Loopback0

   passive enable

  !

  interface GigabitEthernet0/4/0/0.620

  !

mpls ldp

 router-id 0.0.0.20

!

 

R6:

R6#sh run | sec ospf|mpls

router ospf 1

 log-adjacency-changes

 passive-interface Loopback0

 network 10.0.0.6 0.0.0.0 area 0

 network 10.6.20.0 0.0.0.255 area 0

 mpls ldp autoconfig

mpls ldp router-id Loopback0

 

 

and this is the neibourship  they do have:

R6#sh ip ospf nei

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

10.0.0.20         1   FULL/DR         00:00:37    10.6.20.20      FastEthernet0/0.620

 

The problem here is that no LDP session between R6 and XR2 will come up. At the beginning i was thinking that was a Layer 2 issue so i did change the config in order to have:

SW1#sh spanning-tree vlan 620

 

VLAN0620

  Spanning tree enabled protocol rstp

  Root ID    Priority    33388

             Address     0023.5d91.f100

             This bridge is the root

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

 

  Bridge ID  Priority    33388  (priority 32768 sys-id-ext 620)

             Address     0023.5d91.f100

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

             Aging Time  300 sec

 

Interface           Role Sts Cost      Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi0/2               Desg FWD 4         128.2    P2p (XR2)

Fa0/6               Desg FWD 19        128.8    P2p (R6)



and by the way i can ping each other interfaces. So  has anybody idea why the LDP session is not coming up? Forgetting, no authentication involved..



Just adding this:



RP/0/3/CPU0:XR2#sh mpls interfaces 

Sat Apr 29 02:40:45.954 UTC

Interface                  LDP      Tunnel   Enabled 

-------------------------- -------- -------- --------

GigabitEthernet0/4/0/0.620 Yes      No       Yes

GigabitEthernet0/4/0/0.820 No       No       Yes



and this:



R6#sh mpls interfaces 

Interface              IP            Tunnel   BGP Static Operational

FastEthernet0/0.620    Yes (ldp)     No       No  No     Yes        





thanks

Alessio

Comments

  • Give debug MPLS LDP transport events a blast

  • Indeed. You got it. I fixed but it was a crazy error:

     

    R6#

    ldp: Ignore Hello rcvd on FastEthernet0/0.620 with martian transport address, 0.0.0.20

    R6#

    ldp: Send ldp hello; FastEthernet0/0.620, src/dst 10.6.20.6/224.0.0.2, inst_id 0

    ldp: Ignore Hello rcvd on FastEthernet0/0.620 with martian transport address, 0.0.0.20

    R6#

    ldp: Ignore Hello rcvd on FastEthernet0/0.620 with martian transport address, 0.0.0.20

    ldp: Send ldp hello; FastEthernet0/0.620, src/dst 10.6.20.6/224.0.0.2, inst_id 0

     

    and to fix it  i had to delete the IOS XR2 loopback 0 interface and to rewrite it again. Did not work yet but after re-typing the 

    mpls ldp router-id 10.0.0.20 

     

    this is what i have got (debugging mpls ldp transport):

    ldp: Rcvd ldp hello; FastEthernet0/0.620, from 10.6.20.20 (10.0.0.20:0), intf_id 0, opt 0xC

    ldp: ldp Hello from 10.6.20.20 (10.0.0.20:0) to 224.0.0.2, opt 0xC

    ldp: New adj 0x656A41B0 for 10.0.0.20:0, FastEthernet0/0.620

    ldp:    adj_addr/xport_addr 10.6.20.20/10.0.0.20

    ldp: Request adj send hello back on FastEthernet0/0.620 to (xport addr 10.0.0.20) in 1 msec

    ldp: local idb = FastEthernet0/0.620, holdtime = 15000, peer 10.6.20.20 holdtime = 15000

    ldp: Link intvl min cnt 2, intvl 5000, idb FastEthernet0/0.620

    ldp: Opening listen port 646 for 10.0.0.20, 10.6.20.20

    ldp: No MD5 password protection for peer 10.0.0.20:0

    ldp: Registered TCB with LDP TCB database tcb 0x66724520 [key 9358], total 1

    ldp: Open LDP listen TCB 0x66724520; lport = 646; fhost = 10.0.0.20; with normal priority

    ldp: Add listen TCB to list; tcb 0x66724520 [key 9358]; addr 10.0.0.20

    ldp: Send ldp hello; FastEthernet0/0.620, src/dst 10.6.20.6/224.0.0.2, inst_id 0

    ldp: Registered TCB with LDP TCB database tcb 0x66725738 [key 9358], total 2

    ldp: Incoming ldp conn 10.0.0.6:646 <-> 10.0.0.20:50257; with normal priority

    ldp: Found adj 0x656A41B0 for 10.0.0.20 (Hello xport addr opt)

    ldp: New temporary adj 0x658BA514 from 10.0.0.20

    ldp: Real adj 0x656A41B0 bound to 10.0.0.20:0, replacing temp adj 0x658BA514

    ldp: Adj 0x658BA514; state set to closed

    %LDP-5-NBRCHG: LDP Neighbor 10.0.0.20:0 (1) is UP

     

    The rest of the config was fine so the lab was up and working at once. I just lost 3 h on this "martian" thing [:@] !!

    Thanks for your help Keith.

     

    Alessio

  • Because the ospf rid is not an IP address the x.x.x.x you use doesn't matter but the LDP rid needs to be routable. There is an rfc on what is classed as Martian, don't recall the number. 

     

    Aha it's nice to be back on the forum again :)

  • Because the ospf rid is not an IP address the x.x.x.x you use doesn't matter but the LDP rid needs to be routable. There is an rfc on what is classed as Martian, don't recall the number. 

     

    Aha it's nice to be back on the forum again :)

    I guess it is this one? :

     

    http://www.ietf.org/rfc/rfc3704.txt

     

    Alessio

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