Functions and functions of IPv6 Neighbor Discovery

In IPv6, the characteristic performance is IPv6 Neighbor Discovery. Then we will introduce the specific meanings and structural functions in this article. One of the advantages of IPv6 is its flexible routing mechanism. Because the IPv4 network ID is assigned, a router located on the Internet hub is required to maintain a large route table. These routers must know all the routes to forward data packets that may be directed to any node on the Internet. Through its ability to aggregate addresses, IPv6 supports flexible addressing, greatly reducing the size of the route table. In this new addressing structure, the intermediate router must only track the local part of its network to properly forward messages.

IPv6 protocol Neighbor Discovery

Neighbor Discovery provides the following functions:

Vro discovery. This allows the host to identify the local router.

Address Resolution. This allows the node to parse the link layer address for the corresponding next hop address to replace the Address Resolution Protocol [ARP]).

Automatic address configuration. This allows the host to automatically configure the site-local address and global address.

IPv6 protocol Neighbor Discovery uses the Internet Control Message Protocol for IPv6 (ICMPv6) messages, including:

Router Advertisement. The router sends a request based on a pseudo-regular request or responds to the router request. An IPv6 router uses a router advertisement to publish its availability, address prefix, and other parameters.

Router request. A router that is sent by a host and used to send a router advertisement immediately on the request link.

Neighbor request. It is sent by the node for address resolution, duplicate address detection, or for confirming that the neighbor is still accessible.

Neighbor Advertisement. Sent by the node to respond to a neighbor request or notify the neighbor link layer address of a change.

Redirection. A vro sends a node to indicate a better next hop address pointing to a specific target.

What is the difference between the IPv6 Neighbor Discovery protocol and the IPv4 Address Resolution Protocol?

IPv6 no longer implements Address Resolution Protocol ARP) or Reverse Address Resolution Protocol RARP), instead of the corresponding functions in the Neighbor Discovery protocol, the main differences between the IPv6 Neighbor Discovery protocol and IPv4 Address Resolution Protocol are as follows:

In IPv4, The Address Resolution Protocol ARP is an independent protocol that converts IP addresses to link layer addresses and defines different ARP protocols for different link layer protocols. In IPv6, the Neighbor Discovery Protocol NDP includes the ARP function and runs on ICMPv6, which is more general, including more content and applicable to various link layer protocols;

ARP, ICMPv4 router discovery, and ICMPv4 redirection packets are broadcast-based, while NDP neighbor discovery packets are based on efficient multicast and unicast;

The purpose of the accessibility detection is to check whether the host or vro of the corresponding IP Address can send and receive packets. There is no unified solution for IPv4. The Accessibility detection process is defined in NDP to ensure that IP packets are not sent to the "black hole ".