[UDT] Errors in app/cc.h

[Harald s. <sc...@rr...>]

Hi,
there are some errors in the implementation of BIC and Scalable
in app/cc.h.

 o when receiving an DUPACK, m_issthresh is not reduced.
   (m_dCWndSize is set to m_issthresh after the first non duplicate
    ACK arrives. So m_dCWndSize is not reduced at all.)
 o It is necessary to  distinguish between SlowStart and BICSlowStart.
 o If BIC is in BICSlowStart and an DUPACK arrives, BICSlowStart
   must be aborted.

I changed some Parameters Medienberichten in TCP-BIC to achieve an
similar behaviour than Linux-BIC. (BIC is the default Congestion Control
algorithm since Kernel 2.6.13). This can of course easily be revoked....



diff app/cc.h app/cc.h_org
42d41
<       m_bBICSlowStart = false;
113,114c112
<    bool m_bBICSlowStart;
<
---
>
137d134
<           {
139,141d135
<             if (m_dCWndSize >= m_issthresh)
<               m_bSlowStart = false;
<            }
143d136
<           {
145d137
<           }
154d145
<       m_bSlowStart = false;
156,164c147,150
<         {
<          m_issthresh *= 0.5;
<          m_dCWndSize = m_issthresh;
<         }
<       else
<         {
<          m_issthresh=getPerfInfo()->pktFlightSize*0.875;
<          m_dCWndSize=m_issthresh;
<         }
---
>          m_dCWndSize *= 0.5;
>       else
>          m_dCWndSize *= 0.875;
>
243c229
<       if (!m_bBICSlowStart)
---
>       if (!m_bSlowStart)
245,246c231,232
<          if ((m_dTargetWin - m_dCWndSize) < m_iSMax)
<              m_dCWndSize += (m_iSMax/36)/m_dCWndSize;
---
>          if (m_dTargetWin - m_dCWndSize < m_iSMax)
>             m_dCWndSize += (m_dTargetWin - m_dCWndSize)/m_dCWndSize;
248a235
>
256c243
<             m_bBICSlowStart = true;
---
>             m_bSlowStart = true;
271c258
<             m_bBICSlowStart = false;
---
>             m_bSlowStart = false;
283,284c270
<          m_issthresh=(getPerfInfo()->pktFlightSize)*0.7;
<          m_dCWndSize = m_issthresh;
---
>          m_dCWndSize *= 0.875;
287a274
>          {
290c277
<
---
>          }
292d278
<       m_bBICSlowStart = false;
296,299c282,285
<    static const int m_iLowWindow = 16;
<    static const float m_iSMax = 16;
<    static const float m_iSMin = 0.1;
<    static const int m_iDefaultMaxWin = 100000;
---
>    static const int m_iLowWindow = 38;
>    static const int m_iSMax = 32;
>    static const int m_iSMin = 1;
>    static const int m_iDefaultMaxWin = 1 << 29;



Bye,
Harald