Message ID: A 16-byte string uniquely identifying the message
on the network.

Servants SHOULD store all 1's (0xff) in byte 8 of the
GUID. (Bytes are numbered 0-15, inclusive.) This
serves to tag the GUID as being from a modern servant.

Servants SHOULD initially store all 0's in byte 15 of
the GUID. This is reserved for future use.

The other bytes SHOULD have random values.


Don't mess it up with the Servant identifier in Query Hit and Push messages.

Servant Identifier. A 16-byte string uniquely identifying the responding servant on the network. This SHOULD be constant for all Query Hit messages emitted by a servant and is typically some function of the servant's network address. The servant Identifier is mainly used for routing the Push Message