How frames are transfered with OSI or TCP/IP levels

Question

boiz and girlz

I`ve been learning networking for a couple of days, namely about TCP/ip and OSI levels. And i have a question: When a frame arives in my LAN from the Internet, it will be decapsulated, so that a router can understand whom he should deliver it to, but doesnt it mean that that frame will no longer contain a Physical level, which wont let it get to its destination? (I can suppose, that after decapsulation that frame will be once again incapsulated on a router, so that it can arrive the destination with Physical level)

As far as i understand, Physical level is a way to transfer frames.

One more thing: "Why does everyone use the 'Packet Loss', when there should be 'Frame Loss(NOT RELATED TO FPS)'?"

//Just want to find out what i`ve missed and missunderstood.

Thanks in advance.

Answer 1

It's called packet loss because it's experienced at the network level (i.e. IP level). What hosts see is just an IP packet disappearing somewhere on the path.

There are actually two way a packet can be lost:

• The frame can be lost in transmission at the data link level (for instance, the frame couldn't be transmitted on WiFi successfully because of interference).
• The packet could be dropped at the network level (for instance, an IP router is experiencing congestion because the downstream link has insufficient bandwidth).