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opentag:otlib [2012/01/24 04:46]
jpnorair [Cryptographic Interface]
opentag:otlib [2012/01/24 04:59] (current)
jpnorair [Session]
Line 64: Line 64:
  
 ===== Session ===== ===== Session =====
 +//​[[Session|Session main article]]// \\
 The Session Layer defines the session data type and stores the session stack. ​ The Session Data Type is kind of like glue that holds several other layers together. ​ It stores parameters that need to be passed, layer-to-layer,​ and it holds each set of these individually in a stack element. ​ The stack is ordered such that the newest sessions are on top (as stacks generally are), and if the stack gets too full, the oldest sessions are the ones that get the boot.  So, OpenTag (and DASH7 Mode 2, Chapter 8) favor new sessions over old.  This not only is more practical for DASH7 type networks, but it also is very compact and elegant to implement. The Session Layer defines the session data type and stores the session stack. ​ The Session Data Type is kind of like glue that holds several other layers together. ​ It stores parameters that need to be passed, layer-to-layer,​ and it holds each set of these individually in a stack element. ​ The stack is ordered such that the newest sessions are on top (as stacks generally are), and if the stack gets too full, the oldest sessions are the ones that get the boot.  So, OpenTag (and DASH7 Mode 2, Chapter 8) favor new sessions over old.  This not only is more practical for DASH7 type networks, but it also is very compact and elegant to implement.
  
-Each session takes up 8 bytes of SRAM.  A system with more than 8 sessions is kind of extreme.  ​Generally, a 1 session stack is adequate for many sorts of applications,​ a 2 session stack can do most (if not all) applications,​ and 4 to 8 session ​stacks are pretty much all you'll ever need.  The limit is a 255 session stack, which is pretty insane.  ​The implementation of the stack is such that going beyond 8 sessions will want to use a more efficient sort method for the stack (the base method is linear insertion sort with actual memory copying).+Each session takes up 8 bytes of SRAM.  A typical device has a session stack between 2 and 6 levels deep -- anything ​more than an 8-session stack would be special-purpose.  ​1-session stack is adequate for many sorts of applications,​ a 2-session stack can do most (if not all) applications,​ and the default configuration calls for a 4-session ​stack.  The limit is a 255-session stack.  ​If going beyond ​an 8-session stack, you may want to use a more efficient sort method for the stack (the basic method is linear insertion sort).
  
 ===== M2QP ===== ===== M2QP =====
opentag/otlib.txt ยท Last modified: 2012/01/24 04:59 by jpnorair