Error on page 76?

[Roy]

For Window it reads: The window size the sender is willing to accept, in octets. Should sender be changed to receiver?

[vanarnum]

The SENDER is telling the reciever at the opposite end how much memory he has to buffer information from that receiver. This is part of the flow control mechanism so that the sender data doesn't over run the receiver's buffer causing retransmission of the excess data.

[Roy]

The SENDER is telling the reciever at the opposite end how much memory he has to buffer information from that receiver. This is part of the flow control mechanism so that the sender data doesn't over run the receiver's buffer causing retransmission of the excess data.

I guess I'm confused because in chapter one in the review answers it says, "a receiving host can control the transmitter by using flow control. By decreasing the window size, the receiving host can slow down the transmitting host so the receiving host does not overflow its buffers."

Wouldn't the receiver be the one telling the sender, hey I don't have enough room for that window size, please lower it next time you send?

[Roy]

The SENDER is telling the reciever at the opposite end how much memory he has to buffer information from that receiver. This is part of the flow control mechanism so that the sender data doesn't over run the receiver's buffer causing retransmission of the excess data.

I guess I'm confused because in chapter one in the review answers it says, "a receiving host can control the transmitter by using flow control. By decreasing the window size, the receiving host can slow down the transmitting host so the receiving host does not overflow its buffers."

Wouldn't the receiver be the one telling the sender, hey I don't have enough room for that window size, please lower it next time you send? It's the receivers buffer that we are worrying about overflowing not the senders.

Isn't the receiver the one who should decide what window size he's accepting? The sender isn't accepting a certain window size, he's only getting told what to send.

[vanarnum]

Refer to page 20 in Todd Lammle's CCNA book, 6th edition. This explains the flow control mechanism called windowing. The window field in the response packet sent to the transmitter contains the receiver's buffer size. The transmitter will not send more information then the window size specifies. This mechanism works in both directions. Kook at the traces on pages 81 and 82 to see the window field. The number in that field specifies the receive buffer size.

[xx JPRacer xx]

Roy, you are right. It should read receiver. Here's a quote from Upgrading and Repairing Networks 4th Ed. page 384.


Window -- This 16-bit field is used to specify how many blocks of data the receiving computer is able to accept at this time.


And like you said it is correctly stated in chapter one.

[lammle]

Yes, you are correct.

Windowing allows the receiver to control the amount of data that can be transmitted by the sender so the receivers buffer does not overflow...

Thanks!
Todd Lammle

[Roy]

Thanks, that's what I thought.

I wanted to make sure I just wasn't misinterpreting the wording. Again, thank you!