Unicast Address - Zte ZXR10 5900E Series User Manual

ZXR10 5900E Series User Manual (IPv6 Volume)
Global Unicast
Address
Site-Local Unicast
Address
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Allocation
Multicast

Unicast Address

IPv6 unicast address is an interface identifier of single node in
network. Packets that use unicast address as destination address
are sent to interface with this identifier. There are four types of
unicast addresses, as described in follows:
Global unicast address uses strict aggregation of route prefixes.
This reduces entries in routing table. Its format is shown in
3.
T 3 GLOBAL UNICAST ADDRESS FORMAT
ABLE
3 bits
Format prefix Global route
Fields in Figure 31 are described as follows:
1. Format prefix: format prefix of global unicast address, 3 bits.
Currently it is 001.
2. Global route prefix: 45 bits.
3. Site-level aggregation ID: it is used to divide subnets by single
organization in its own address space. IPv6 subnets have the
similar function as that of IPv4. It is up to 65,535 subnets in
IPv6.
4. Interface ID: it is used to identify the interface on a link. In-
terface ID must be unique on a link even in a much larger
scale. In many situations, it is the same with the interface link
layer address, or it is based on the interface link layer address.
Identifiers of global unicast address and other kind of address
types must be 64 bits, in modified EUI-64 format.
For all IEEE 802 interface types (including Ethernet interface and
FDDI interface), the first three bytes (24 bits) of interface ID are
obtained from Organization Unique Identifier (OUI) MAC address.
The fourth and fifth bytes are fixed hexadecimal number FFFE. The
last three bytes (24 bits) are obtained from the last three bytes
of MAC address. Before interface ID is finished, it is necessary to
set the seventh bit in the first byte. If the value of this bit is 0, it
means it is a local management interface ID. If it is 1, it means it
is a global unique interface ID.
For other interface types, such as serial interface,
reply, the method to form an interface ID is the same as that of
IEEE 802 interface types. As these types of interfaces do not have
MAC addresses, the MAC address is the first MAC address in device
MAC address pool.
Site-local unicast address consists of prefix FEC0::/10 (1111 1110
11), subnet ID and interface ID. It is allocated to a site to use
and does not occupy a global unicast address. Site-local unicast
Prefix
1111 1111
45 bits 16 bits
Site-level
prefix aggregation ID
Occupation Rate of
Address Space
1/256
Table
64bits
Interface ID
ATM and frame