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If you're not familiar with MAC or IP addressing., were going to cover that in another section, but for now it's enough to know that when two hosts communicate on a network, they're using these MAC and IP addresses as the destination when the data is sent.
So far, so good. But what if one host is sending multiple flows of information to the remote host? Let's say that the PC at 10.1.1.1 is sending three different kinds of information to the PC at 10.1.1.2:
- transferring a file via Trivial File Transfer Protocol ( TFTP )
- email via Simple Mail Protocol ( SMTP )
- opening a remote connection via Telnet
If you're not familiar with those three protocols, don't worry about it - you will be before you're done with this course. For now, it's enough to know that one PC is sending three different types of information to the other, and the MAC and IP source and destination addresses for all three transmissions is going to be the same. How can the receiving host tell TFTP from SMTP if that's the case?
We need a way for the recipient to differentiate on data flow from the other, and since the source and destination MAC and IP addresses will be the same for all three flows, that won't do. What will do is the TCP or UDP port number, While these three data flows will have the same Layer 2 (MAC) and Layer 3(IP) source and destination addresses, they'll have different, pre-assigned port numbers.
Port Numbers Multiplexing :- Mixing of data to different ports when transmitted.
____________________________________________
If you're not familiar with MAC or IP addressing., were going to cover that in another section, but for now it's enough to know that when two hosts communicate on a network, they're using these MAC and IP addresses as the destination when the data is sent.
So far, so good. But what if one host is sending multiple flows of information to the remote host? Let's say that the PC at 10.1.1.1 is sending three different kinds of information to the PC at 10.1.1.2:
- transferring a file via Trivial File Transfer Protocol ( TFTP )
- email via Simple Mail Protocol ( SMTP )
- opening a remote connection via Telnet
If you're not familiar with those three protocols, don't worry about it - you will be before you're done with this course. For now, it's enough to know that one PC is sending three different types of information to the other, and the MAC and IP source and destination addresses for all three transmissions is going to be the same. How can the receiving host tell TFTP from SMTP if that's the case?
We need a way for the recipient to differentiate on data flow from the other, and since the source and destination MAC and IP addresses will be the same for all three flows, that won't do. What will do is the TCP or UDP port number, While these three data flows will have the same Layer 2 (MAC) and Layer 3(IP) source and destination addresses, they'll have different, pre-assigned port numbers.
Port Numbers Multiplexing :- Mixing of data to different ports when transmitted.
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