3com 4210 PWR 9-Port 3CR17341-91-ME User Manual
Product codes
3CR17341-91-ME
IPv6 Overview
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Leading zeros in each group can be removed. For example, the
above-mentioned address can be represented in shorter format as
2001:0:130F:0:0:9C0:876A:130B.
above-mentioned address can be represented in shorter format as
2001:0:130F:0:0:9C0:876A:130B.
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If an IPv6 address contains two or more consecutive groups of zeros, they can
be replaced by the double-colon :: option. For example, the above-mentioned
address can be represented in the shortest format as
2001:0:130F::9C0:876A:130B.
be replaced by the double-colon :: option. For example, the above-mentioned
address can be represented in the shortest format as
2001:0:130F::9C0:876A:130B.
c
CAUTION: The double-colon :: can be used only once in an IPv6 address.
Otherwise, the device is unable to determine how many zeros the double-colon
represents when converting it to zeros to restore the IPv6 address to a 128-bit
address.
Otherwise, the device is unable to determine how many zeros the double-colon
represents when converting it to zeros to restore the IPv6 address to a 128-bit
address.
An IPv6 address consists of two parts: address prefix and interface ID. The address
prefix and the interface ID are respectively equivalent to the network ID and the
host ID in an IPv4 address.
prefix and the interface ID are respectively equivalent to the network ID and the
host ID in an IPv4 address.
An IPv6 address prefix is written in IPv6-address/prefix-length notation, where
IPv6-address is an IPv6 address in any of the notations and prefix-length is a
decimal number indicating how many bits from the left of an IPv6 address are the
address prefix.
IPv6-address is an IPv6 address in any of the notations and prefix-length is a
decimal number indicating how many bits from the left of an IPv6 address are the
address prefix.
IPv6 address classification
IPv6 addresses mainly fall into three types: unicast address, multicast address and
anycast address.
anycast address.
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Unicast address: An identifier for a single interface, similar to an IPv4 unicast
address .A packet sent to a unicast address is delivered to the interface
identified by that address.
address .A packet sent to a unicast address is delivered to the interface
identified by that address.
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Multicast address: An identifier for a set of interfaces (typically belonging to
different nodes), similar to an IPv4 multicast address. A packet sent to a
multicast address is delivered to all interfaces identified by that address.
different nodes), similar to an IPv4 multicast address. A packet sent to a
multicast address is delivered to all interfaces identified by that address.
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Anycast address: An identifier for a set of interfaces (typically belonging to
different nodes).A packet sent to an anycast address is delivered to one of the
interfaces identified by that address (the nearest one, according to the routing
protocols’ measure of distance).
different nodes).A packet sent to an anycast address is delivered to one of the
interfaces identified by that address (the nearest one, according to the routing
protocols’ measure of distance).
n
There are no broadcast addresses in IPv6. Their function is superseded by multicast
addresses.
addresses.
The type of an IPv6 address is designated by the format prefix. Table 383 lists the
mapping between major address types and format prefixes.
mapping between major address types and format prefixes.
Table 383 Mapping between address types and format prefixes
Type
Format prefix (binary)
IPv6 prefix ID
Unicast
address
address
Unassigned address
00...0 (128 bits)
::/128
Loopback address
00...1 (128 bits)
::1/128
Link-local address
1111111010
FE80::/10
Site-local address
1111111011
FEC0::/10
Global unicast address other forms
-
Multicast address
11111111
FF00::/8