Updated the text for step 5 of the example as follows (changes in the second
part of the paragraph):

   5.  The message is intercepted at GN2.  The GIST layer identifies the
       message as relevant to a local signalling application, and passes
       the NSLP payload and flow description upwards to it.  This
       signalling application in GN2 indicates to GIST that it will peer
       with GN1 and so GIST should proceed to set up any routing state.
       In addition, the signalling application continues to process the
       message as in GN1 (compare step 1), passing the message back down
       to GIST so that it is sent further downstream, and this will
       eventually result in the message reaching the flow receiver.
       GIST itself operates hop-by-hop, and the signalling application
       joins these hops together to manage the end-to-end signalling
       operations.

The example in section 3.7 can leave the impression that the forwarding
responsibility to join multiple signalling sessions together lies in the GIST
layer, whereas in fact it lies in the NSLP layer. GIST only carries out the
forwarding when the NSLP is bypassed.