What is the ICMPv6 type for Neighbor Advertisement (NA) messages?

Neighbor Advertisement (NA) messages are an essential part of the Neighbor Discovery Protocol in IPv6, which is used for various purposes, including discovering other nodes on the network and determining their link-layer addresses. The specific ICMPv6 type for Neighbor Advertisement messages is defined as 136. This type of message is sent in response to a Neighbor Solicitation message, which carries requests for the link-layer address of a particular IPv6 address.

The Neighbor Advertisement message serves to inform other nodes of the sender's existence and can also be used to convey additional information, such as the sender's link-layer address. This mechanism is crucial for maintaining an efficient and dynamic local link environment in an IPv6 network, enabling automatic address resolution and facilitating the connection between devices. Understanding the specific types associated with ICMPv6 messages helps network professionals manage and troubleshoot IPv6 networks more effectively.