OSPF for IPv6
Carsten Strotmann
Created: 2025-01-30 Thu 09:49
Routing in IPv6
Routing
- Routing in IPv6 is very much like in IPv4
- The protocols use underlying IPv6 features such as extension headers and router alert
- But from the operator perspective IPv6 routing “feels” common
Common IPv6 routing protocols
- IGP (Interior Gateway Protocol)
- RIPng
- IS-IS for IPv6
- OSPFv3
- EIGRP for IPv6
- EGP (Exterior Gateway Protocol)
- BGP4+
OSPFv3
OSPFv3
- OSPFv3 is the IPv6 version of OSPFv2
- It usually runs on IPv6 only
- RFC 7949 defines "OSPFv3 over IPv4 for IPv6 Transition"
- OSPFv3 runs over each link, instead each subnet
- OSPFv3 relies on IPSec support in IPv6 for authentication (see RFC 4552 Authentication/Confidentiality for OSPFv3)
- It usually runs on IPv6 only
OSPFv3
- OSPFv3 multicast communication addresses:
- AllSPFRouters -
ff02::5 - AllDRouters (OSPF designated router and backup-designated router) -
ff02::6
- AllSPFRouters -
OSPFv3
- OSPFv3 message changes
- IPv6 addresses moved from header into payload
- OSPF router-id, area-id and link-state-id are still 32bit
- These values are displayed as dotted-decimal
- These values do not represent IPv4 addresses!
- They should be set explicit (not derived from IPv4 addresses)
OSPFv3
- RFC 5838 "Support of Address Families in OSPFv3" specifies how
address families other than IPv6 can be used in OSPFv3
- Requires IPv6 as the transport of the routing information between OSPFv3 router
OSPFv3 Updates
- RFC 6969 "OSPFv3 Instance ID Registry Update" defines half of the "Unassigned" number space in the IANA "OSPFv3 Instance ID Address Family Values" for private use
- RFC 8362 "OSPFv3 Link State Advertisement (LSA) Extensibility" extends the LSA format by encoding the existing OSPFv3 LSA information in Type-Length-Value (TLV) tuples and allowing advertisement of additional information with additional TLVs.
HomeNet
- OSPFv3 is one of the base protocols of the IETF HomeNet protocol family https://tools.ietf.org/wg/homenet/
- RFC 7503 "OSPFv3 Autoconfiguration" defines extensions to OSPFv3 that allow complete autoconfiguration ("plug-and-play network")
Questions?
