Internet Control Message Protocol Version 6 (ICMPv6) provides the same diagnostic services as Internet Control Message Protocol Version 4 (ICMPv4), and it extends the functionality for some specific IPv6 functions that did not exist in IPv4.
第 6 版網際網路控制訊息協定（ICMPv6）提供與第 4 版網際網路控制訊息協定（ICMPv4）相同的診斷服務，並擴充了一些 IPv4 沒有的特定 IPv6 功能。
ICMPv6 enables nodes to perform diagnostic tests and report problems. Like ICMPv4, ICMPv6 implements two kinds of messages—error messages (such as Destination Unreachable, Packet Too Big, or Time Exceeded) and informational messages (such as Echo Request and Echo Reply).
ICMPv6 讓節點能執行診斷測試並回報問題。與 ICMPv4 一樣，ICMPv6 實作兩種訊息，錯誤訊息（例如目的地無法到達、封包過大或存活時間逾時）以及資訊性訊息（例如 Echo 請求與 Echo 回覆）。
ICMPv6 Type Field Descriptions
ICMPv6 類型欄位說明
ICMPv6 Type Field ICMPv6 類型欄位 | Description 說明 |
1 1 | Destination Unreachable 目的地無法到達 |
128 128 | Echo Request Echo 請求 |
129 129 | Echo Reply Echo 回覆 |
133 133 | Router Solicitation 路由器邀請 |
134 134 | Router Advertisement 路由器通告 |
135 135 | Neighbor Solicitation 鄰居邀請 |
136 136 | Neighbor Advertisement 鄰居通告 |
The ICMPv6 packet is identified as 58 in the Next Header field. Inside the ICMPv6 packet, the Type field identifies the type of ICMP message. The Code field further details the specifics of this type of message. The Data field contains information that is sent to the receiver for diagnostics or information purposes.
ICMPv6 封包在下一個標頭（Next Header）欄位中以 58 表示。在 ICMPv6 封包內，類型（Type）欄位辨識 ICMP 訊息的種類，代碼（Code）欄位則進一步說明此類訊息的細節，資料（Data）欄位包含傳送給接收端用於診斷或提供資訊的內容。
ICMPv6 is used on-link for router solicitation and advertisement, for neighbor solicitation and advertisement, and for the redirection of nodes to the best gateway.
ICMPv6 用於鏈路上的路由器邀請與通告、鄰居邀請與通告，以及將節點重新導向至最佳閘道。
Neighbor solicitation messages are sent on the local link when a node wants to determine the data link layer address of another node on the same local link. After receiving the neighbor solicitation message, the destination node replies by sending a neighbor advertisement message. This message includes the data link layer address of the node sending the neighbor advertisement message. Hosts send router Solicitation messages to locate the routers on the local link, and routers respond with router advertisements that enable autoconfiguration of the hosts.
當一個節點想要判斷同一本地鏈路上另一個節點的資料鏈結層位址時，會在本地鏈路上傳送鄰居邀請訊息。目的節點收到鄰居邀請訊息後，會回覆一則鄰居通告訊息，其中包含傳送該鄰居通告訊息之節點的資料鏈結層位址。主機會傳送路由器邀請訊息以尋找本地鏈路上的路由器，路由器則以路由器通告回應，讓主機得以進行自動設定。