Zte ZXR10 T1200, Руководство пользователя

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ZXR10 T600/T1200 User Manual (IPv6 Volume)
indicating this is the aggregatable global unicast ad-
dress.
– TLA ID field
This is the top-level aggregation identifier, including the
routing information about the addresses at the highest
level. Here, it refers tothe 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.
– RES field
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.
– NLA ID field
This is the next-level aggregation identifier with 24-bit.
This identifier are used by some institutions (including
large-size ISPs and other institutions that provide public
network access) to control the top-level aggregation for
address space arrangement.
Such institutions can divide this 24-bit field for use in ac-
cordance with their own addressing hierarchical structures.
In this way, an entity can divide two bits of address space
into four internal top-level routes, and allocate the other
22 bits of address space to other entities (for example, a
small local ISP).
When these entities obtain enough address space, they can
subdivide the obtained space in the same way as mentioned
above.
– SLA ID field
This is the site aggregation identifier and is used by
some institutions to arrange their internal network
structures. Each institution can create its own internal
hierarchical network structure in the same way as that
of IPv4.
When the 16-bit field is dedicated to the plane address
space, there are at most 65,535 different subnets avail-
able. If the first eight bits are used for the internal ad-
vanced routing of this institution, then there will be 255
advanced subnets available, and each advanced subnet
can have up to 255 sub-subnets.
– Interface identifier field
This is a 64-bit field, containing 64-bit values of the
IEEE EUI-64 interface identifier.
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Special Address & Reserved Address
In the first 1/256 IPv6 address space, the first 8 bits 0000
0000 of all the addresses are reserved. Most of the vacant
address spaces are used for special addresses, including:
– Undesignated address
This is an all-zero address and is used if no valid address
is available. For example, if a host does not obtain an
IPv6 address upon its initial startup from the network,
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