سلام به همگی
راستش توی این درس زیاد مشکل دارم، الانم هر چی این متن رو میخونم نمی تونم درک کنم که چی میخواد بگه، امیدوارم دوستان راهنمایی کنن...

در مبحث Packet Switching، موضوعی عنوان میشه با نام Store-and-forward packet switching، متاسفانه در این موضوع مطلبی در مورد فرمول time to transmit the packet is L/R seconds نوشته شده که در فایل پیوست مشخص کردم. که نمیتونم بفهمم که چرا در مثال متن کتاب به هنگام انتقال داده از روتر به مقصد end-to-end delay رو ۴L/R بدست آورده ...

متنی که در فایل پیوست کامل تر نوشته شده :

Now let’s calculate the amount of time that elapses from when the source
begins to send the first packet until the destination has received all three packets.
As before, at time L/R, the router begins to forward the first packet. But also at time
L/R the source will begin to send the second packet, since it has just finished sending
the entire first packet. Thus, at time 2L/R, the destination has received the first
packet and the router has received the second packet. Similarly, at time 3L/R, the
destination has received the first two packets and the router has received the third
packet. Finally, at time 4L/R the destination has received all three packets!

ممنون