[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[ns] Vegas Retransmission mechanism



To start with, I am using ns-2.1b7.

1) Does Vegas decrease its cwnd after receiving the 1st non-duplicate
ACK to
 3/4 of its value before the 1st loss was detected??

2) Is the original Vegas (even in ns-2.1b7) have a problem where the
packet transmissions during recovery decreases until no packets could be
transmitted?? At this point, since no ACKs can be received, a timeout
has to occur.

From what I understand, Vegas can only recover 2 more packets beyond the

1st one lost during one RTT?? If that's the case I wanna make changes to
vegas to ensure that it recovers all packets in cwnd that were sent
prior to the invocation of fast retransmit mechanism.
I just need to change vegas to make sure that vegas keeps transmitting
packets at the 3/4th rate continously, but not sure where exactly in the
code this could be done.

I want to keep track of the last segment sent before duplicate ACKs were
received.
Until an ack for this latter segment is received, I want to make a
modification to vegas code to ensure recovery is not terminated. I'm
finding trouble in knowing where exactly in the code is recovery
terminated. Can anyone help me with this? Does vegas already do what I'm
thinking of doing?

Can anyone please pin point to me where can I find these issues in the
code. I really appreciate any help or comments.

yours
Mohammed