Hi Jarno,

>The method by which the flow state is cleared from the IPv6 nodes is to be defined by 
>the flow state establishment method used to set up the state. This implies that IPv6 
>nodes SHOULD NOT establish any flow-specific state unless so instructed by a specific 
>flow state establishment method. 

I don't agree with the "SHOULD NOT" above...

There are some potential uses for flow identification that do not rely on
any sort of flow establishment mechanism or signalling, such as the use of
flow labels for load balancing.

To have a useful flow label for these mechanisms, an IPv6 node simply labels 
all of the packets in a given TCP/SCTP connection or UDP communication with 
the same flow label,making some basic effort not to re-use flows too often -- 
such as starting with a random number and monotonically increasing it for 
each new connection or communication.  

It would be fairly trivial to assign a flow label in this fashion -- not
much harder than setting it to zero.  So, you get a reasonable return for
very little work.

Of course, this type of non-unique flow labeling isn't consistent with using
flow labels to cache next-hop information, for example.  For those more
sophisticated needs, a real flow establishment (and maintenance) method may
be needed.  But, I don't think that we should require a more sophisticated
method to be present in order to use the flow label at all.

Margaret


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