How ARP functions in FTP process.

[minkumar]

 

An  Example:

Whever we type the following command:

%FTP bsdi

Following steps happen:

The FTP client, convert the hostname (bsdi) into its 32-bit IP address. This function is called a resolver in the DNS (Domain Name System), This conversion is done using the DNS.

1. The FTP client asks its TCP to establish a connection with that IP address.
2. TCP sends a connection request  to the remote host by sending a packet to its IP address.
3. If the destination host is on a locally attached network, the frame can be sent directly to that host. If the destination host is on a remote network, the IP routing function determines the Internet address of a locally attached next-hop router to send the packet  to. In either case the data is sent to a host or router on a locally attached network.
4. Assuming an Ethernet, the sending host must convert the 32-bit IP address into a 48-bit Ethernet address. A translation is required from the ip to mac l. This is the function of ARP.

   ARP is intended for broadcast networks where many hosts or routers are connected to a single network.

5. ARP sends an Ethernet frame called an ARP request to every host on the network. This is called a broadcast. . The ARP request contains the IP address of the destination host (whose name is bsdi) and is the request if you are owner of the request , respond to me with your hardware address.
6. The destination host's ARP layer receives this broadcast, recognizes that the sender is asking for its hardware address, and replies with an ARP reply.This reply contains the IP address and the corresponding hardware address.
7. The ARP reply is received and the packet that forced the ARP request-reply to be exchanged can now be sent.
8. The Packet  is sent to the destination host.

#Please post comments if there are any queries and rate if useful

[askhuran]

Just my suggestions to the above:

4. ARP does not CONVERT but helps to resolve IP to MAC address

5. ARP attempts to resolve the destination IP only if it is in the same network, otherwise the frame is to be sent to the gateway or next-hop. So in that case, ARP would attempt resolution of gateway IP

To the title question "How ARP functions in FTP Process"

This does not matter to ARP whether the upper layer (Application) process is FTP or HTTP or DNS

So we can say, "How ARP functions"