The question arises as to
which packets generated by a source should carry nonzero IPv6 flow labels. For
some applications the answer is obvious. Small exchanges of data should have a
zero flow label because it is not worth creating a flow for a few packets.
Real-time flows should have a flow label; such flows are a primary reason flow
labels were created. A more difficult issue is what to do with peers sending
large amounts of best-effort traffic (e.g. TCP connections). Make a case for
assigning a unique flow label to each long-term TCP connection. Make a case for
not doing this.about 150 words with reference