----------------------------------------------------------------------
                              FORWARD PATH
----------------------------------------------------------------------

Interest +---------+  +-----+ (path label) +--------+ (match) Interest
-------->| Content |->| PIT | ------------>| Label  |---------------->
         |  Store  |  +-----+              | Lookup |
         +---------+   | \ (no path label) +--------+
          |            |  \                    |\(path label mismatch)
Data      |            |   \                   | \
<---------+            v    \                  |  \
                  aggregate  \                 |   \
                              \                |    \
                               \               |     +-----+  Interest
                                +--------------|---->| FIB | -------->
                                               |     +-----+
InterestReturn (NACK)                          v        | (no route)
<----------------------------------------------+<-------+


----------------------------------------------------------------------
                              REVERSE PATH
----------------------------------------------------------------------

InterestReturn(NACK)  +-----+(update path label)  InterestReturn(NACK)
<---------------------|     |<----------------------------------------
                      |     |
Data   +---------+    | PIT |  (update path label)                Data
<------| Content |<---|     |<----------------------------------------
       |  Store  |    |     |
       +---------+    +-----+
                         |
                         | (no match)
                         v