Ethernet Technology

A host uses an Ethernet card for communication within a LAN

1. How does the Ethernet card knows that it must resend a packet ?

2. Can the host send directly a packet to another host that does not belong to the same physical network

1. review the OSI model. It will explain what causes a resend and how that is handled.

2. yes if there is a router between the local subnet and the remote one.

Thanks for the help...
but the only problem is that after reviewing it only i couldnt figure it out thats y i posted this here..

if anyone has the knowdledge abt it.. plz let me know thanks

A google search yielded one aspect below:

http://www.intel.com/support/expres...0fast/22447.htm

This is resend at the physical layer. Each layer has a mechanism to ask for a resend if there is incomplete recieve.

There are a number of sources of this information. Internet searches and networking books will give you more detail.

Best of luck!

For ethernet please read on cisco web site and research CSMA/CD, ( also depends on protocol UDP will not know it was lost and TCP will unless monitored by layer4). Not sure what you are asking on the second question as internaly (same network) it will resolve and send VIA MAC address (layer 2) if not it will be answered by the router with its MAC address and be routed via IP (layer 3). ( please to read on ARP, Proxy ARP, IP routing)