This document outlines few comparisons of OSPFv3 and OSPFv2 Routing Protocol. OSPFv3 has few similarities with that of IPv4 version i.e. OSPFv2 in some ways, like Packet Type, Interface Type, Neighbor Discovery Pattern, LSA flooding & aging.
OSPFv3 and v2 Differences:
>Protocol processing per-link, not per-subnet
>Removal of addressing semantics
>Addition of Flooding scope
>Explicit support for multiple instances per link
>Use of IPv6 link-local addresses
>Authentication method changes
>Packet format, LSA’s header format changes
>Handling of unknown LSA types
Protocol processing per-link, not per-subnet:
IPv6 uses the term "link" instead of "subnet" or "network" to define a medium used to communicate between nodes at the link layer. Multiple IP subnets can be assigned to a single link, and two nodes can communicate with each other even if they do not share a common IP subnet.
OSPfv3 Packet/Interface Type
OSPFv3 Packet TypeOSPFv3 Interface Type
Type 1 - Hello
Type 2 - Database Description
Type 3 - Link State Request
Type 4 - Link State Update
Type 5 - Link State Acknowledgement
OSPFv3 Header Comparison
Router & Area ID
Interface Specific and Entire Area
Note: In OSPFv3, Instance ID is a new field that is used to have multiple OSPF process’ instance per link. By default it is 0 and for any additional instance it is increased, instance ID has local link significance only. OSPFv3 routers will only become neighbors if the instanceIDs match. It is thus possible to have multiple routers on a broadcast domain and all run Ospfv3 but not all of them becoming neighbours.
OSPFv3 Hello Packet and Functioning
Note: Interface ID is a 32-bit number uniquely identify an interface, virtual link gets its own interface ID.
As compared, OSPFv3 does not require a Network mask to form an adjacency formation. Adjacency is formed on the link local as v6 runs on per link instead of per subnet.
OSPFv3 Option field is 24-bit as that of V2 8-bits
Dead intervals field reduced to 16 bits from 32.
OSPFv3 LSA Types
LSA Type or the function code matches the same LSA type as in OSPFv2
Type 3 is now called inter-area-prefix-LSA
Type 4 is now called inter-area-router-LSA
Two new LSA type have been added (Link LSA and Intra-Area Prefix LSA)
Note:Intra-Area Prefix LSA is a new LSA in OSPFv3 and used in order to advertise one or more IPv6 prefixes. In OSPFv2 the intera-area prefix information was carried in the router and network LSA's (Type 1 & 2).
Support for Multiple Instances Per Link:
Instance ID is a new field that is used to have multiple OSPF process instance per link. In order for 2 instances talk to each other they need to have the same instance ID. By default it is 0 and for any additionalinstance it is increased, Instance ID has local link significance only.
Authentication method changes:
OSPFv2 authentication is achieved by implementing a shared secret and MD5 HMAC supported as part of the OSPFv2 protocol. OSPFv3 does away its own support for authentication entirely, instead relying on the more flexible IPsec framework offered by IPv6.
1)May I know the difference of ISIS metric-type internal and external while redistributing ? 2)I have configured metric-type external alone without metric keyword while redistributing but it is not effecting. May I know the reason why does not I...
Hi Team,I have Configured NAT64 on an ASR. It appears everything is working as required until the outgoing DNS64 Addressed IPv6 packets 'hit the NAT64 server (ASR)' on Int GE0/0/0. Int GE0/0/3.31211 is connected to the IPv6 only host. Keen to hear what th...
For the corp network, we have a velocloud router as the edge device connects to a branch office's velocloud router. Velocloud devices are managed by a 3rd part company which provided our internet connectivity. They work with ATT or Spectrum to provide us ...
Hi everyone, I am very new to Cisco Routing, so please don't mind if this is a trivial question: On my router, the interface gig0/0/1 is the WAN interface and gets an IP address via DHCP from my ISP. I have created a DHCP pool (192.168.1.0/24 wi...
Hi all, I have a new Cisco FirePower 1010 that I have configured for a small remote office. I have most of what I need working including the S2S VPN Tunnel to an ASA 5515.Now, I'm trying to get Cisco APs to lite up over the tunnel and I need to configure ...