3com S7906E Manuel De Montage

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An IPv6 address prefix is written in IPv6-address/prefix-length notation, where the IPv6-address is in 
any of the notations above mentioned, and prefix-length is a decimal number indicating how many bits 
from the left-most of an IPv6 address is the address prefix. 
IPv6 address classification 
IPv6 addresses fall into three types: unicast address, multicast address, and anycast address. 
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. 
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. 
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 target interface is nearest to the source, according to a routing protocol’s measure of 
distance). 
 
 
There are no broadcast addresses in IPv6. Their function is replaced by multicast addresses. 
 
The type of an IPv6 address is designated by the first several bits called format prefix. 
 lists the 
mappings between address types and format prefixes. 
Table 1-1 Mappings between address types and format prefixes 
Type 
Format prefix (binary) 
IPv6 prefix ID 
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 
Unicast 
address 
Global unicast 
address 
other forms 
— 
Multicast address 
11111111 FF00::/8 
Anycast address 
Anycast addresses are taken from unicast address space and 
are not syntactically distinguishable from unicast addresses. 
 
Unicast address 
There are several types of unicast addresses, including aggregatable global unicast address, link-local 
address, and site-local address. 
The aggregatable global unicast addresses, equivalent to public IPv4 addresses, are provided for 
network service providers. This type of address allows efficient prefix aggregation to restrict the 
number of global routing entries.