TP-Link TL-SG2424 User Manual page 101

0XFF at the start of the address identifies the address as being a multicast address.

Flags have 4 bits:

The high-order flag is reserved, and must be initialized to 0.
(1)
R: Set to 0 to indicate this IPv6 multicast address does not contain an embedded RP
(2)
address; set to 1 to indicate this IPv6 multicast address contains an embedded RP address.
When this bit is set to 1, the P and T bits must also be set to 1.
P: Set to 0 to indicate this IPv6 multicast address is not based on a unicast prefix; set to 1 to
(3)
indicate this IPv6 multicast address is based on a unicast prefix. When this bit is set to 1,
the T bit must also be set to 1.
T: Set to 0 to indicate that this address is an IPv6 multicast address permanently assigned
(4)
by the Internet Assigned Numbers Authority (IANA); set to 1 to indicate that this address is
a transient, or dynamically assigned IPv6 multicast address.
Scope is a 4-bit value used to limit the scope of the multicast group. The values are as follows:

Value
0、3、F
1
2
4
5
6、7、9～D
8
E
Group ID: 112 bits, IPv6 multicast group identifier that uniquely identifies an IPv6 multicast

group in the scope defined by the Scope field.
Indication
reserved
Interface-Local scope
Link-Local scope
Admin-Local scope
Site-Local scope
unassigned
Organization-local scope
Global scope
Table 8-2 Indications of the Scope
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