Description

On JUNOS routers, routing-instances are used to separate OSPF instances, and JUNOS follows RFC5838 to use ID's for different address families (AF's):

Instance ID # 0 - # 31 IPv6 unicast AF
Instance ID # 32 - # 63 IPv6 multicast AF
Instance ID # 64 - # 95 IPv4 unicast AF
Instance ID # 96 - # 127 IPv4 multicast AF
Instance ID # 128 - # 255 Unassigned

In this scenario, a Cisco router configures OSPF3 instance ID arbitrarily with 192 and talk to JUNOS Router for family IPv6, which causes OSPF neighborship fail.

Symptoms

JUNOS router configures ospf3 for IPv6 routes is having issue to build neighborship with Cisco IOS due to Cisco peer configures OSPF instance ID not following RFC5838.

When turning on JUNOS protocols ospf3 traceoptions flag all, we can see the trace log indicating the issue:

OSPF packet ignored: no matching interface from fe80::f64e:5ff:fe15:1940, IFL 328 realm id 192  <<<

Cisco router as our OSPF3 neighbor may configure like the following:

router ospfv3 3661
  router-id 137.189.192.249
...
interface Vlan192
  ospfv3 cost 3
  no ospfv3 passive-interface
  ospfv3 priority 60
  ospfv3 instance 192
  ipv6 router ospfv3 3661 area 0.0.0.0

Solution

JUNOS is working as per RFC5838 standard. A neighbor router to talk OSPF3 for IPv6 family needs to configure instance ID comply with RFC5838.

On the other hand, if a JUNOS router needs to talk with multiple OSPF instances, it has to separate them by routing-instances or logical-systems

Modification History

.

Related Information

RFC5838 - Support of Address Families in OSPFv3
https://www.rfc-editor.org/rfc/rfc5838.txt