Flow Label Specification
A packet is classified to a certain flow by the <Flow Label, Source Address, Destination Address> triplet
- Allows the same Flow Label value to be used with different destinations
- Enables definition of Flow Label based Session object in RSVP
- Flow state establishment methods may wildcard either of the addresses
- Enables the RSVP Wildcard-Filter reservation style to e.g. multicast destinations with multiple (wildcarded) senders
- The Flow Label value is meaningless out of the context of the addresses
- Non-zero Flow Label value for labeled flows, no other requirements
The IPv6 node assigning a Flow Label value MUST keep track of all the <Flow Label, Source Address, Destination Address> triplets in use
- To prevent mixing separate flows together
- Programming interface needed, but out of scope
- Three abstract functions defined in the draft
The Flow Label value MUST be delivered unchanged to the destination