1. If the initial sequence number of a SYN packet is x, the ACK
   sequence number should be x+1 for this SYN.

2. The emulator may freeze after sometime.  It seems that this is 
   a problem of Fishnet, and the simulator does not have this problem.  
   You can leave this aside as long as your code works for simulator.

3. Your design document should describe your transport layer design.
   In particular, you should document your transport service
   interface.  You should also include in the design document
   important high level implementation decisions you have made.  For
   example, whether you choose to use a linear array or a hash table
   for the socket space.  If you make design decisions that are not
   typical (as we have covered in class), please make efforts to
   justify your choices.  However, don't over-elaborate.

4. Your code should contain appropriate comments.  Try to be succinct,
   don't comment on the obvious, but on important implementation
   decisions, such as the algorithm used to search in the socket space
   for the purpose of demultiplexing.

5. You should use your designed transport service interface to build a
   test case 'application' to convince the TA that your
   implementation works.  For example, you could build the 'transfer'
   application suggested on the assignment description page, choose a
   reasonable data pattern, and verify the received data at the
   server(receiver) side application.