Zte ZXR10 5900E Series, Configuration Manual

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ZXR10 5900E Series Configuration Guide (IPv6)
Figure 1-3 Structure of an IPv6 unicast address
The IPv6 unicast address can be classified into the following categories:
l
Aggregatable Global Unicast Address
This is another kind of aggregation, which is independent of Internet Service
Provider ( ISP ). The provider aggregatable addresses must be changed as a
provider changes, while the exchange-based addresses are directly located by
an IPv6 switching entity. The exchange provides address blocks, and users and
providers conclude contracts for the network access.
Such network access is either directly provided by a provider, or indirectly provided
by an exchange. However, the routing is through the exchange. In this way, a user
needs not to address again when it changes a provider. At the same time, users
are allowed to use multiple ISPs to process single-block network address.
Aggregatable global unicast addresses include all the addresses whose three
starting bits are 001, which can be used as prefixes for other unallocated
unicast. Table 1-2 lists the aggregatable global unicast address fields.
Table 1-2 Aggregatable Global Unicast Address Fields
3 13 8 24 16 64
FP TLA ID RES NLA ID SLA ID Interface identifier
The table includes the following fields.
à
FP
This is the 3-bit format prefix in an IPv6 address, indicating to which address
category in the IPv6 address space this address belongs. Currently, the field
is 001, indicating this is the aggregatable global unicast address.
à
TLA ID
This is the top-level aggregation identifier, including the routing information
about the addresses at the highest level. Here, it refers to the routing
information with the most hosts in network interconnection. Currently, this
field is 13-bit and can obtain at most 8,192 different top level routes.
à
RES
This is an 8-bit field and reserved for future use. It is likely to be used for
extending the top- or next-level aggregation identifier field.
à
NLA ID
This is the next-level aggregation identifier with 24-bit. This identifier is
used by some institutions (including large-size ISPs and other institutions
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