a couple of questions regarding tcp-sink.cc

[Miten Mehta <mmehta@cs.tamu.edu>]

Hi,

I have a couple of questions regarding tcp-sink.cc. 

1. 

class Acker::inline int Seqno() const { return (next_ - 1); }
(defined in tcp-sink.h)

TcpSink::ack() uses Acker::Seqno() to put seq no (ack no. in this case) in
ack as "ntcp->seqno() = acker_->Seqno();"
My question is why (next_ - 1) is put as ack no. and not next_ as in
normal TCP.

2. 
in Acker::update(int seq) (defi9ned in tcp-sink.cc), we have following:
    if (seq > maxseen_) {
        int i;
        for (i = maxseen_ + 1; i < seq; ++i)
            seen_[i & MWM] = 0;
        maxseen_ = seq;
        seen_[maxseen_ & MWM] = 1;
        seen_[(maxseen_ + 1) & MWM] = 0;
    }

Does seen[] talk in terms of packet no.? or bytes? If later then why
"seen_[maxseen_ & MWM] = 1;" and "seen_[(maxseen_ + 1) & MWM] = 0;" and
not "seen_[(maxseen_ + no_of_bytes_in_pkt) & MWM] = 0;" ??

even seqno_ seems to behave like packet no. and not as the first byteno. 
of the packet. Am I right?

Any pointers or suggestions? Documentation talks about only sending
agents, it does not have much detail of sink agents. 

Thanking you in advance.

Miten.

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Miten N. Mehta                                 	Graduate Research Assistant 
3902, Collegemain, #908				Computer Science
Bryan, 						Texas A & M University
Texas-77801.					College Station, TX-77843

Tel.#(409) 846 1451                            	(409) 845 5007 
			E-mail# miten@tamu.edu
            Home Page : http://www.cs.tamu.edu/people/mmehta

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