IPv6 Routing

Question 1

IPv6 Routing Phases

Answer 1

• On-the-fly routing: use the routing table
• Proactive routing: build routing tables
  
  • Manual configuration
    
    • static routing
  • Distribute destination information thorughuot the network
    
    • routing protocols

Routers must support IPv4 as well as IPv6

Question 2

Enabling IPv6 Routing

Answer 2

Most routers support IPv6 forwarding (most likely disabled)

Sample config:

Router#configure terminal

Router(config)#ipv6 unicast-routing

• IPv6 addresses con be configured on interfaces
• IPv6 packets are forwarded

Question 3

IPv6 Routing table

Answer 3

Routing based on LPM (as per IPv4)

IPv6 and IPv4 are dealt with as two independent protocols (separate routing tables

Question 4

IPv6 Routing protocols types

Answer 4

• Integrated Routing:
  
  • A single protocol to advertise destination of both IP verions.
  • Pros
    
    • No need for duplicated mechanisms (advertisement and fault detection)
  • Cons
    
    • v4 or v6 will transport protocol messages? a new protocol might have bugs
    • v4 and v6 networks might have different topologies.
• Ships in the night
  
  • Each address family uses a distinct protocol (completely independent)
  • Pros
    
    • Different routing protocols can be used (tune choice to topology/scenario)
    • Smoother migration
    • Simpler troubleshooting
  • Cons
    
    • Duplicated mechanism

IS-IS and MP-BGP both offer integrated routing funcitonalities. MP-BGP also offers Ships in the night.

All the other routing protocols used the “Ships in the night approach”.