[spring] Question on draft-ietf-spring-srv6-network-programming-12

[Christian Hopps <[e-mail]>]

In sections 4.13, (implicitly in 4.14) and 4.15 a set of steps is indicated. As far as I can tell the processing of the IPv6 header chain in all cases is terminated. e.g.,

"
   When N receives a packet whose IPv6 DA is S and S is a local End.BM
   SID, does:

  S01. When an SRH is processed {
  S02.   If (Segments Left == 0) {
...
               Interrupt packet processing and discard the packet.
  S04.   }
  S05.   If (IPv6 Hop Limit <= 1) {
...
               Interrupt packet processing and discard the packet.
  S07.   }
  S09.   If ((Last Entry > max_LE) or (Segments Left > (Last Entry+1)) {
...
               Interrupt packet processing and discard the packet.
  S11.   }
...
  S15.   Submit the packet to the MPLS engine for transmission to the
            topmost label.
  S16. }
"

The text then says:

   When processing the Upper-layer header of a packet matching a FIB
   entry locally instantiated as an SRv6 End.BM SID, process the packet
   as per Section 4.1.1.

Why would I ever be processing the upper-layer header at this point?

Thanks,
Chris.