Each unicast or anycast address corresponds to a single solicited-node multicast address, which is often used in neighbor discovery and duplicate The node, and the node joins the multicast group that corresponds to its IPv6 unicast or anycast address. When a node has an IPv6 unicast or anycast address, a solicited-node multicast address is generated for To communicate without any configuration, making link-local addresses widely used in neighbor discovery and stateless address configuration.ĭevices do not forward IPv6 packets with the link-local address as a source or destination address toįigure 11-3 shows the link-local address format.įigure 11-5 IPv6 multicast address formatĪ solicited-node multicast address is generated using an IPv6 unicast or anycast address of a node. This mechanism enables two IPv6 nodes on the same link When IPv6 runs on a node, a link-local address that consists of a fixed prefix and an interface ID in EUI-64 format is automatically assigned to each interface of the node. A link-local address uses a link-local prefix of FE80::/10 as the first 10 bits (1111111010 in binary) and an interface ID as Link-local addresses are used only in communication between nodes on the same local link. Similar to an IPv4 subnet number, there are a maximum of 64 bits for both the global routing prefix and subnet ID. Subnet ID: is used by organizations to construct a local network (site). Currently, the first 3 bits of every assigned global routing A global routing prefix is comprised of at least 48 bits. Global routing prefix: is assigned by a service provider to an organization. These components are described as follows: IPv6 global unicast addresses support route prefix summarization, helping limit the numberįigure 11-2 shows a global unicast address consisting of a global routing prefix, subnet ID, and interface ID.įigure 11-2 Global unicast address format The loopback address cannot be used as the source or destination IP address of packets needing to be forwarded.Īn IPv6 global unicast address is an IPv6 address with a global unicast prefix, which is similar to an IPv4 public address. Is usually used as the IP address of a virtual interface, such as a loopback interface. Similar to the IPv4 loopback address 127.0.0.1, the IPv6 loopback address is used when a node needs to send IPv6 packets to itself. Devices do not forward packets with an unspecified address as the source IP address. (NS) messages, in duplicate address detection. It can be used as the source IP address of some packets, such as Neighbor Solicitation The IPv6 unspecified address is 0:0:0:0:0:0:0:0/128 or ::/128, indicating that an interface or a node does not have an IP address. IPv6 defines multiple types of unicast addresses, including the unspecified address, loopback address, global unicast address, link-local address, and unique local Packets sent toĪn IPv6 unicast address are delivered to the interface identified by that address. Since each interface belongs to a node, the IPv6 unicast address of any interface can identify the relevant node. IPv6 Unicast AddressĪn IPv6 unicast address identifies an interface. Instead, a multicast addressĬan be used as a broadcast address. Unlike IPv4, there is no broadcast IPv6 address. I can ping the loopback IPs locally on each respective router.IPv6 addresses can be classified as unicast, multicast, or a new class called anycast. I can ping the link local ips from each respective router to the other but I cannot ping the loopback interface IPs from the either router to the other. Sh ipv6 int brief outputs: FE80::21D:71FF:FE53:6C00 for Vlan10 interface IP Sh ipv6 int brief outputs: FE80::219:7FF:FEFE:FC00 for Vlan10 interface IP Is this not supported? Am I doing something wrong? I was hoping that I would be able to use the link local IPv6 addresses of the port channel between the routers to route the loopback address information, however, this does not seem to be working in Cisco IOS. The issue I am having now is attempting to get the loopback addresses to route between routers. In the end I essentially decided to use /128 on loopback interfaces using globally unique IPv6 space out of a /64 reserved for loopback numbering across our entire network. I have been doing some reading on IPv6 and have read a few different best practices guides and all of them seem to have conflicting information on the best way to assign loopback addresses.
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