ZXR10 5900E Series Configuration Guide (IPv6)
Table 1-5 Multicast Address Format
8
4
4
112
1111111
Flags
Scope
Group identifier
The first byte of the address format is set to full-one, identifying it as a multicast
address. The multicast address occupies the entire 1/256 of the IPv6 address space.
The other parts except the first byte of the multicast address format contain the
following three fields:
l
Flags field
This field consists of four single bit flags. Currently, only the bit-4 is designated to
indicate that whether this address is a well-known multicast address designated
by the Internet numbering institution, or a temporary multicast address used in a
specific occasion.
If this flag bit is set to zero, it indicates that this address is a well-known address.
If this flag bit is set to one, it indicates that this address is a temporary address.
The other three flag bits are reserved for future use. The initialization value is 0.
l
Scope field
This is a 4-bit field and is used to indicate the range of multicast. That is, whether
a multicast group only includes nodes within the same local network, the same
site or the same institution, or includes nodes that resides anywhere in the IPv6
global address space. The possible 4-bits value ranges from 0 to 15. For the
corresponding ranges, refer to
Table 1-6 Multicast Scope Value
Hex
Decimal
Value
0
0
Reserved
1
1
Node-local range
2
2
Link-local range
3
3
Unallocated
4
4
Unallocated
5
5
Site-local range
6
6
Unallocated
7
7
Unallocated
8
8
Institution-local range
9
9
Unallocated
10
A
Unallocated
11
B
Unallocated
12
C
Unallocated
1-8
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