3Com Switch 4210 9-Port, Configuration Manual

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IPv6 Overview 529
Where, FF02:0:0:0:0:1:FF is permanent and consists of 104 bits, and XX:XXXX is
the last 24 bits of an IPv6 address.
Interface identifier in IEEE EUI-64 format
Interface identifiers in IPv6 unicast addresses are used to identify interfaces on a
link and they are required to be unique on that link. Interface identifiers in IPv6
unicast addresses are currently required to be 64 bits long. An interface identifier is
derived from the link-layer address of that interface. Interface identifiers in IPv6
addresses are 64 bits long, while MAC addresses are 48 bits long. Therefore, the
hexadecimal number FFFE needs to be inserted in the middle of MAC addresses
(behind the 24 high-order bits).To ensure the interface identifier obtained from a
MAC address is unique, it is necessary to set the universal/local (U/L) bit (the
seventh high-order bit) to "1". Thus, an interface identifier in EUI-64 format is
obtained.
Figure 190 Convert a MAC address into an EUI-64 address
Introduction to IPv6
Neighbor Discovery
Protocol
The IPv6 neighbor discovery protocol (NDP) uses five types of ICMPv6 messages to
implement the following functions:
■
Address resolution
■
Neighbor unreachability detection
■
Duplicate address detection
■
Router/prefix discovery
■
Address autoconfiguration
■
Redirection
Table 385 lists the types and functions of ICMPv6 messages used by the NDP.
00000000 00010010 00110100 00000000 10101011 11001101
00000000 00010010 00110100 11111111 11111110 00000000 10101011 11001101
0012-3400-ABCD
00000010 00010010 00110100 11111111 11111110 00000000 10101011 11001101
0212:34FF:FE00:ABCD
MAC address:
Represented in binary:
Insert FFFE
Set U/L bit:
EUI-64 address:
Table 385 Types and functions of ICMPv6 messages
ICMPv6 message Function
Neighbor solicitation (NS)
message Used to acquire the link-layer address of a neighbor
Used to verify whether the neighbor is reachable
Used to perform a duplicate address detection