same functionality in osi model

Question

Transport layer and datalink layer of OSI model provide similar functionality. If one of said was already there, why was the other needed

These two layers are totally different to be honest. Why do you think they are similar? If you can provide some examples, it will be easier to answer your question. — Demento, Apr 25 '11 at 21:07
Your question is based on a false premiss, but I don't know why anybody should now be concerned with the OSI model nearly 30 years after the project was superceded and now that there is nothing in the universe that actually conforms to it. You should be learning the TCP model at this time. — user207421, Feb 09 '19 at 01:23

score 0 · Accepted Answer · answered Apr 25 '11 at 21:08

0

They do provide some similar functionality, but at a different level. The link layer provides for communications for MAC addresses on the same LAN; the transport layer provides for communication between any devices anywhere.

answered Apr 25 '11 at 21:08

jcomeau_ictx

37,688
6
92
107

score 0 · Answer 2 · answered Apr 26 '11 at 03:30

A good design typically includes the concept of separation of concerns. That is, the data link layer need only be concerned with how to get packets to other hosts on that specific link. Remember that Ethernet is not the only link type in the world. You might need to get packets to the other side of a PPP link over an analog modem. Since the network layer is separate, you can use a different data link type and your network layer packets can remain the same.

score 0 · Answer 3 · answered Apr 26 '11 at 09:33

You may refer to an image here for reference.

Physical: Only knows about bits. Handled byires and hubs
Data Link: Knows about MAC addresses. Handled by layer 2 switches
Network: Knows about IP addresses. Handled by routers or layer 3 switches
Transport: TCP comes here

same functionality in osi model

3 Answers3