Information Technology

IPv6 Routing Configurations (Static & Dynamic Routing)

25 Aug 2023
Networking

Note: Fundamental Routing Concepts - Routing (Concepts, Protocols and Configurations), EIGRP (Enhanced Interior Gateway Routing Protocol) and OSPF (Open Shortest Path First)

Enable IPv6 Routing on Router

Router(config)# ipv6 unicast-routing

IPv6 Static Routing

  • ipv6-prefix : Destination network address of the remote network to be added to the routing table.
  • prefix-length : Prefix length of the remote network to be added to the routing table.
  • ipv6-address : The next-hop router’s IPv6 address.
  • exit-interface : The outgoing interface (one of the router’s own interfaces that is directly connected to the next-hop router) to forward packets to the destination network.
Router-1(config)# ipv6 route <ipv6-prefix>/prefix-length [<ipv6-address> or <exit-interface>]

Recursive Static Route :

Router-1(config)# ipv6 route 2001:DB8:ACAD:2::/64 2001:DB8:ACAD:4::2

Directly Attached Static Route :

Router-1(config)# ipv6 route 2001:DB8:ACAD:2::/64 Serial0/0/0

Fully Specified Static Route :

Router-1(config)# ipv6 route 2001:DB8:ACAD:2::/64 Serial0/0/0 2001:DB8:ACAD:4::2

Default Static IPv6 Route :

  • ::/0 : Matches any IPv6 prefix regardless of prefix length.
  • ipv6-address : The next-hop router’s IPv6 address.
  • exit-interface : The outgoing interface (one of the router’s own interfaces that is directly connected to the next-hop router) to forward packets to the destination network.
Router-1(config)# ipv6 route ::/0 [<ipv6-address> or <exit-interface>]

IPv6 Floating Static Route :

Router-1(config)# ipv6 route ::/0 2001:DB8:ACAD:4::2 5

Verify IPv6 Static Routes

This command shows the IPv6 routing table :

Router# show ipv6 route static

EIGRP for IPv6

1) Initialize the EIGRP routing process and enter the EIGRP router configuration mode :

  • AS number functions as a process ID. The AS number used for EIGRP configuration is only significant to the EIGRP routing domain.
  • AS number configured in a router must be the same as the neighbor’s AS number.
Router(config)# ipv6 router eigrp <AS-number>

2) Set the EIGRP Router-ID for a router :

  • Router-ID is used to uniquely identify each router in the EIGRP routing domain.
  • Router-ID is in IP address format, which is four decimal numbers separated by dots. For example, 2.2.2.2
Router(config-router)# eigrp router-id 2.2.2.2

3) By default, the EIGRP for IPv6 process is in a shutdown state and the command below is required to activate the EIGRP for IPv6 process :

Router(config-router)# no shutdown

4) Unlike EIGRP for IPv4 which uses the network command, EIGRP for IPv6 is configured directly on the interface using the ipv6 eigrp <AS-number> interface configuration command :

Router(config)# int GigabitEthernet 0/0
Router(config-if)# ipv6 eigrp 2

5) Suppress routing updates on an interface :

  • Passive interfaces prevent EIGRP routing updates over a specified router interface.
Router(config-router)# passive-interface <interface-id>

6) EIGRP for IPv6 (Default Route Propagation)

Router(config-router)# redistribute static

7) EIGRP for IPv6 (Hello and Hold Timers) :

Router(config-if)# ipv6 hello-interval eigrp <AS-number> <seconds>
Router(config-if)# ipv6 hold-time eigrp <AS-number> <seconds>

OSPFv3

1) Initialize OSPF routing process and enter the OSPF router configuration mode :

  • The process ID value represents a number between 1 and 65,535 and is selected by the network administrator. The process ID value is locally significant.
  • It is considered best practice to use the same process ID on all OSPF routers.
Router(config)# ipv6 router ospf <process-id>

2) Explicitly configure Router-ID for a router :

  • Router-ID is in IP address format, which is four decimal numbers separated by dots. For example, 1.1.2.2
Router(config-router)# router-id 1.1.2.2

3) Unlike OSPFv2 which uses the network command, OSPFv3 is configured directly on the interface using the ipv6 ospf <process-id> area <area-id> interface configuration command :

Router(config)# int GigabitEthernet 0/0
Router(config-if)# ipv6 ospf 10 area 1

4) Suppress OSPFv3 routing on an interface :

  • Passive interfaces prevent the transmission of routing messages through an interface, but still allow that network to be advertised to other routers.
Router(config-router)# passive-interface <interface-id>

5) OSPFv3 Tuning (Default Route Propagation) :

  • This command instructs the router to be the source of the default route information and propagate the default static route in OSPF updates.
Router(config-router)# default-information originate

6) OSPFv3 Tuning (Modify OSPF Intervals) :

  • To restore the default interval, use the “no” form in this command.
Router(config-if)# ipv6 ospf hello-interval <seconds>
Router(config-if)# ipv6 ospf dead-interval <seconds>

References