TAILIEUCHUNG - Understanding Linux Network Internals 2005 phần 7

NUD_PROBE trạng thái chuyển tiếp, họ sẽ được giải quyết khi các máy chủ địa phương xác định xem hàng xóm có thể truy cập. Xem "Xác nhận reachability." Các tập tiếp theo của giá trị đại diện cho một nhóm của các quốc gia đặc biệt thường không bao giờ thay đổi một khi được giao | This document was created by an unregistered ChmMagic please go to http to register it. Thanks NUD_INCOMPLETE A solicitation has been sent but no reply has been received yet. In this state there is no hardware address to use not even an old one as there is with nud_stale . NUD_REACHABLE The address of the neighbor is cached and the latter is known to be reachable there has been a proof of reachability . NUD_FAILED Marks a neighbor as unreachable because of a failed solicitation request either the one generated when the entry was created or the one triggered by the NUD_PROBE state. NUD_STALE NUD_DELAY NUD_PROBE Transitional states they will be resolved when the local host determines whether the neighbor is reachable. See the section Reachability Confirmation. The next set of values represents a group of special states that usually never change once assigned NUD_NOARP This state is used to mark neighbors that do not need any protocol to resolve the L3-to-L2 mapping see the section Special Cases . The section Start of the arp constructor Function in Chapter 28 shows how and why this state is set in IPv4 ARP. But even though the name of this state suggests that it applies only to ARP it can actually be used by any neighboring protocol. NUD_PERMANENT The L2 address of the neighbor has been statically configured . with user-space commands and therefore there is no need to use any neighboring protocol to take care of it. See the section System Administration of Neighbors in Chapter 29. . Derived states In addition to the basic states listed in the previous section the following derived values are defined just to make the code clearer when there is a need to refer to multiple states with something in common NUD_VALID An entry is considered to be in the NUD_VALID state if its state is any one of the following which represent neighbors believed to have an available address Simpo PDF Merge 9Ud Split Uuregistered ẠergiQU - Pttp This

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