Enabling IPv6 on Cisco Routers.
As you must know; IPv6 is the latest version of the Internet Protocol (IP), which is the system that assigns unique IP addresses to devices and networks on the Internet. IPv6 was created to replace IPv4, which has a limited number of addresses and cannot support the growing number of connected devices.
IPv6 uses 128-bit addresses, which can support up to 340 trillion trillion devices, compared to IPv4’s 32-bit addresses, which can support only 4.3 billion devices. IPv6 also offers other benefits, such as improved security, performance, and multicast capabilities.
By default, IPv6 traffic-forwarding is disabled on a Cisco router. It must be activated between interfaces by using the global configuration command – ipv6 unicast-routing. The global configuration command must be used in both Stateful (DHCPv6) and Stateless autoconfiguration.
There are two basic steps used to activate IPv6 on a Cisco router:
i. First, you must activate IPv6 traffic-forwarding on the router, and
ii. then you must configure each interface that requires IPv6.
Command syntax for enabling IPv6 on Cisco routers:
When a network router interface is configured with an ipv6 address, a link-local address will be configured automatically for the interface.
You must specify the entire 128-bit IPv6 address or specify to use the 64-bit prefix by using the eui-64 option.
IPv6 Address Configuration Example
From the above IPv6 address configuration example, router1 is shown connected to an IPv6 WAN to router2 with a subnet prefix address of 2001:db8:3c4d:2::/64.
We used the following commands:
R1(config)#ipv6 unicast-routing ( configure the router to activate IPv6 routing and configure the router fa0/1 interface).
The EUI-64 option is used to create the 64-bit MAC address.
Note.
The MAC address of the Ethernet Fa0/1 interface is 0260.3d47.1720.
Using the show ipv6 interface fa0/1 command, the MAC address is displayed as part of the IPv6 address with the Hex characters FFFE (16 bits) added in the middle, which expands the 48-bit MAC address to create the IPv6 64-bit link-local address.
R1#show ipv6 interface fa0/1
Fa0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::260:3dFF:FE47:1720
Global unicast addresses:
2001:DB8:C18:1:260:3EFF:FE47:1720, subnet is 2001:DB8:C18:1::/64
Joined group addresses:
FF02::1:FF47:1720
FF02::1
FF02::2
MTU is 1500 bytes
