[ns] ns-2.1b7 release announcement

[Ya Xu <yaxu@ISI.EDU>]

Ns-2.1b7 has been released.  Instructions for getting and building ns are
at <http://www.isi.edu/nsnam/ns/ns-build.html>. The previous
release is 2.0b6. 

What's New in ns-2.1b7
 
- new models: 
 
  - wireless: 
    - additional wireless propagation models: shadowing, Friis
        free-space (previously in two-ray-ground model, now also
        stand-alone),
    - added simple mini-frame-based TDMA, a new MAC protocol
    - simple energy model for wireless nodes (including idle time energy
        consumption) 
    - adaptive fidelity algorithms for ad hoc routing (BECA, AFECA) 
        from Ya Xu
    - directed diffusion, flooding, and omnicient multicast modules
      including codes, test suits, scenarios, and examples from Chalermek
Intanagonwiwat              
  - wired: 
    - link-state routing protocols (added but not yet documented) 
    - MPLS added based on contributed code from Gaeil Ahn
        (added but not documented) 
    - RED enhancements (first_rest_, queue-in-bytes_) from Floyd
 
  - general: 
    - Real Audio traffic model (alpha quality) 
    - PLM code (a congestion control approach) contributed from
        Arnaud Legout at Eurecom
    - added TCP rate-halving code contributed from Mathis, Semke, Mahdavi,
      and Lahey
    - added RIO code ontributed from Yun Wang, Wenjia Fang, and J. Scott
    - several extentions to one-way TCP (noFastRetransmit,
        RFC2581_immediate_ack_etc.) 
 
  - support and bug fixes: 
    - additional validations (test-all-links) 
    - generic debug_ flag in ns-object to enable debugging
    - wireless nodes now emit trace records to allow nam visualziation
    - better support for header disabling to save memory
    - node creation code restructured to allow easier composition of
        components (new classifiers can be put "in front" of nodes
        with a standard API) 
    - wireless nodes an now have multiple interfaces (radios) 
    - support for tcltk-8.3
    - real-time scheduler fixes
    - some code now requires STL; this is autoconf detected    
    - fixes to make Linux run with IEEE standard float point on x86
    - delay_parse now replaced by time_parse (in tcl/lib/ns-lib.tcl) 
    - many bug fixes (in one-way TCP, ECN, full TCP, SACK, TFRC, etc.) 

USC/ISI