Monday, 9 March 2020

OSPFv2 VS OSPFv3

OSPFv3 which is covered in RFC 5340 is a IPv6 link-state interior routing protocol which originates from OSPFv2. OSPFv3 is not backward compatible with OSPFv2 which supports only IPv4 addressing.

General information
OSPFv2 - protocol number 89, all routers multicast 224.0.0.5, DRs multicast on 224.0.06

OSPFv3 - next header value 89, all routers multicast FF02::5, DRs multicast on FF02::6

Here are few things in common:
- both utilise Shortest Path First algorithm  
- five messages types: Hello, Database Description, LSDR, LSDU, LSAck
- link-state advertisement 
- flooding
- DR election
- areas
- timers and metrics are also the same

Differences between OSPFv2 and OSPFv3:
- changes in LSAs
- OSPFv3 utilise per link processing (per subnet), OSPFv2 per interface processing
- in OSPFv3 all neighbours are identified by Router ID whereas in OSPFv2 on Broadcast networks    and NBMA links neighbours are identified by interface ID.
- OSPFv3 adds link-local flooding scope
- OSPFv3 use link-local addresses as a source and destination.

Plumbing... QoS

Rule no 1. QoS does not help in situations where there is no enough bandwidth but helps optimize performance by prioritization of the traffi...