Connectivity Guide

As an alternative to stateless autoconfiguration, you can enable a network host to obtain IPv6 addresses using a DHCP server
via stateful autoconfiguration using the ipv6 address dhcp command. A DHCPv6 server uses a prefix pool to configure a
network address on an interface. The interface ID automatically generates.
Manally configured addresses
An interface can have multiple IPv6 addresses. To configure an IPv6 address in addition to the link-local address, use the ipv6
address ipv6-address/mask command. Enter the full 128-bit IPv6 address, including the network prefix and a 64-bit
interface ID.
You can also manually configure an IPv6 address by assigning:
● A network prefix with the EUI-64 parameter using the ipv6 address ipv6-prefix eui64 command. A 64-bit
interface ID automatically generates based on the MAC address.
● A link-local address to use instead of the link-local address that automatically configures when you enable IPv6 using the
ipv6 address link-local command.
Configure IPv6 address
OS10(config)# interface ethernet 1/1/8
OS10(conf-if-eth1/1/8)# ipv6 address 2001:dddd:0eee::4/64
Configure network prefix
OS10(config)# interface ethernet 1/1/8
OS10(conf-if-eth1/1/8)# ipv6 address 2001:FF21:1:1::/64 eui64
Configure link-local address
OS10(config)# interface ethernet 1/1/8
OS10(conf-if-eth1/1/8)# ipv6 address FE80::1/64 link-local
Stateless autoconfiguration
When an interface comes up, OS10 uses stateless autoconfiguration to generate a unique link-local IPv6 address with a
FE80::/64 prefix and an interface ID generated from the MAC address. To use stateless autoconfiguration to assign a globally
unique address using a prefix received in router advertisements, use the ipv6 address autoconfig command.
Stateless autoconfiguration sets an interface in Host mode, and allows the interface connected to an IPv6 network to
autoconfigure IPv6 addresses and communicate with other IPv6 devices on local links. A DHCP server is not required for
automatic IPv6 interface configuration. IPv6 devices on a local link send router advertisement (RA) messages in response to
solicitation messages received at startup.
Perform stateless autoconfiguration of IPv6 addresses using:
Prefix
advertisement
Routers use router advertisement messages to advertise the network prefix. Hosts append their
interface-identifier MAC address to generate a valid IPv6 address.
Duplicate
address
detection
An IPv6 host node checks whether that address is used anywhere on the network using this mechanism
before configuring its IPv6 address.
Prefix
renumbering
Transparent renumbering of hosts in the network when an organization changes its service provider.
IPv6 provides the flexibility to add prefixes on RAs in response to a router solicitation (RS). By default, RA response messages
are sent when an RS message is received. The system manipulation of IPv6 stateless autoconfiguration supports the router
side only. Neighbor Discovery (ND) messages advertise so the neighbor can use the information to auto-configure its address.
Received ND messages are not used to create an IPv6 address.
Inconsistencies in RA values between routers are logged. The values checked for consistency include:
● Current hop limit
● M and O flags
● Reachable time
● Retransmission timer
● MTU options
● Preferred and valid lifetime values for the same prefix
Layer 3
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