Pointers please - OSPFv3 vs Cisco IOS XR

[Elmar K. Bins]

Hi everybody,

I am very certain somebody has experienced similar issues and solved them; I
did not find any pointers - please throw them at me. If this is new or unsolved,
please help me forward, I can get more output, naturally.

Thank you for your interest already!

Elmar.



The setup:
  - Pair of Cisco ASR9K running IOS XR  trunked to a Juniper EX.
  - FreeBSD 12.1-RELEASE-p3 with bird 2.07, on an access port of that switch.
  - Straightforward OSPF setup on the XR, simple BIRD setup on the BSD.


The issue:
  - BIRD connects nicely on OSPFv2 (for IPv4), all's good.
  - BIRD stays "alone" on OSPFv3 (for IPv6), the Cisco box stays in state EXSTART/DROTHER


The awkwardness:
  - OSPF for IPv4 works just fine. XR config is identical.
  - Quagga ospf3d does the job just fine.


The XR config:

router ospfv3 <instance>
 router-id <router-1>
 default-information originate
 area 0
  interface TenGigE0/1/0/23.4


The BIRD config (snippets):

=== v4 config ===

protocol ospf v2 {
  area 0 {
    interface "lo0" { stub; };
    interface "*"   {       };
  };

  ipv4 {
    import filter ospf_v4_in;
    export filter ospf_v4_out;
  };
}

=== v6 config ===

protocol ospf v3 {
  area 0 {
    interface "lo0" { stub; };
    interface "*"   {       };
  };

  ipv6 {
    import filter ospf_v6_in;
    export filter ospf_v6_out;
  };
}


The BIRD outputs:

ospf1      OSPF       master4    up     2020-05-27    Running
ospf2      OSPF       master6    up     2020-05-27    Alone

Name       Proto      Table      State  Since         Info
ospf2      OSPF       master6    up     2020-05-27    Alone
  Channel ipv6
    State:          UP
    Table:          master6
    Preference:     150
    Input filter:   ospf_v6_in
    Output filter:  ospf_v6_out
    Routes:         0 imported, 0 exported, 0 preferred
    Route change stats:     received   rejected   filtered    ignored   accepted
      Import updates:              1          0          1          0          0
      Import withdraws:            0          0        ---          1          0
      Export updates:              0          0          0        ---          0
      Export withdraws:            0        ---        ---        ---          0


The relevant *ahem* BIRD debug log output (yes, I googled)

2020-05-31 13:08:15.080 <RMT> ospf2: Bad DBDES packet from nbr <router-1> on igb0 - I-bit mismatch (7)


The Cisco side of things (debug ipv6 ospf <instance> adj)

 May 31 13:09:16.278 UTC: ospfv3[1021]: ADJ: Send DBD to <server> on TenGigE0/1/0/23.4 seq 0x8ce5d69 opt R/E/V6 flag I/M/MS len 28 mtu 1500
 May 31 13:09:16.278 UTC: ospfv3[1021]: ADJ: Retransmitting DBD to <server> on TenGigE0/1/0/23.4 [1]
 May 31 13:09:16.278 UTC: ospfv3[1021]: ADJ: Recv DBD fr <server> on TenGigE0/1/0/23.4 seq 0x8ce5d69 opt R/E/V6 flag NONE len 108 mtu 1500 state EXSTART
 May 31 13:09:16.278 UTC: ospfv3[1021]: ADJ: Build DBD summary list for <server>
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ: Built DBD summary list in 0 ms for <server>, 65 entries
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   new: type 2001 lsid 0x0 adv <server> seq 0x800000af age 612
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   new: type 2009 lsid 0x0 adv <server> seq 0x800000af age 612
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   new: type 0008 lsid 0x1 adv <server> seq 0x800000af age 612
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ: Send DBD to <server> on TenGigE0/1/0/23.4 seq 0x8ce5d6a opt R/E/V6 flag M/MS len 1228 mtu 1500
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ: Build REQ packet for <server>
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   type 2001 lsid 0x0 adv <server>
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   type 2009 lsid 0x0 adv <server>
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ:   type 0008 lsid 0x1 adv <server>
 May 31 13:09:16.279 UTC: ospfv3[1021]: ADJ: Send REQ packet to <server>, length 36
 May 31 13:09:16.280 UTC: ospfv3[1021]: ADJ: Recv DBD fr <server> on TenGigE0/1/0/23.4 seq 0x8ce5d6a opt R/E/V6 flag NONE len 28 mtu 1500 state EXCHANGE
 May 31 13:09:16.280 UTC: ospfv3[1021]: ADJ: Send DBD to <server> on TenGigE0/1/0/23.4 seq 0x8ce5d6b opt R/E/V6 flag I/M/MS len 28 mtu 1500
 May 31 13:09:16.281 UTC: ospfv3[1021]: ADJ: Recv DBD fr <server> on TenGigE0/1/0/23.4 seq 0x8ce5d6b opt R/E/V6 flag I/M/MS len 28 mtu 1500 state EXSTART