2 Comments on “Which option is a valid IPv6 multicast address?”
koraasays:
This is confusing. As all of the choices except C are not closely related to a multicast address, we can say C is the answer [A and B don’t have the first 8 bits of 1’s, and D is a wrong IPv6 address as there is no such thing as ‘g’ in hex].
But lets look at C. An IPv6 multicast address has the first 16 bits of format
[8bits of 1’s][4 bits for flags][4 bits for scope ID]
But in C, the scope ID is 3, which is not one of the currently defined scope ID values (defined decimal values are 0,1,2,5,8,14,15).
This is confusing. As all of the choices except C are not closely related to a multicast address, we can say C is the answer [A and B don’t have the first 8 bits of 1’s, and D is a wrong IPv6 address as there is no such thing as ‘g’ in hex].
But lets look at C. An IPv6 multicast address has the first 16 bits of format
[8bits of 1’s][4 bits for flags][4 bits for scope ID]
But in C, the scope ID is 3, which is not one of the currently defined scope ID values (defined decimal values are 0,1,2,5,8,14,15).
Any thoughts?
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https://www.ietf.org/rfc/rfc7346.txt
+——+————————–+————————-+
| scop | NAME | REFERENCE |
+——+————————–+————————-+
| 0 | Reserved | [RFC4291], RFC 7346 |
| 1 | Interface-Local scope | [RFC4291], RFC 7346 |
| 2 | Link-Local scope | [RFC4291], RFC 7346 |
| 3 | Realm-Local scope | [RFC4291], RFC 7346 |
| 4 | Admin-Local scope | [RFC4291], RFC 7346 |
| 5 | Site-Local scope | [RFC4291], RFC 7346 |
| 6 | Unassigned | |
| 7 | Unassigned | |
| 8 | Organization-Local scope | [RFC4291], RFC 7346 |
| 9 | Unassigned | |
| A | Unassigned | |
| B | Unassigned | |
| C | Unassigned | |
| D | Unassigned | |
| E | Global scope | [RFC4291], RFC 7346 |
| F | Reserved | [RFC4291], RFC 7346 |
+——+————————–+————————-+
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