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Now when it says difference between Ethernet 2 and Thank you for your help. Reply to newbie Notify me about replies to my post Post Reply. Walter Roberson Contact options for registered users. Show Quoted Text. Reply to Walter Roberson. There is no Logical-Link control in these frames, and the frame payload starts immediately after the Type field.
Finally, the last frame is the frame of a so-called Cisco Discovery Protocol. Notice again that this frame is identified as IEEE So in fact, this last frame is an SNAP frame. To put it simply, if you are going to look at an IPv4 or IPv6 communication, it will be practically always encapsulated into Ethernet II frames because those are the most efficient in terms of overhead.
So basically correct me if I'm wrong we could say that we have to styles of Ethernet framing :. Just a small correction. In wired copper, fiber Ethernet networks, we commonly have three Ethernet frame variants:. The I suggest you do not bother with this frame format too much. The frame format is the Layer2 protocol. The choice of Ethernet frame formats is on the higher protocol above Layer2 that asks Layer2 to provide specific encapsulation capabilities.
Let me put it this way: When a software engineer writes an IPv4 driver for an operating system, a part of this IPv4 driver has to use the frame transmission facilities provided by the driver of the network card. When calling the functions to transmit a frame, the IPv4 driver also tells the network card driver how it wants the packet to be encapsulated - whether it should be DIX, Theoretically, it could be any one of these.
However, a part of formal specification of IPv4 also deals with how the packets shall be encapsulated into various data link layer frames including Ethernet. So for IPv4, there are several normative references:. RFC says:. So there you have it - you are supposed to use the Ethernet frame that uses the Type field which is, obviously, DIX. This RFC is more complex to read but it basically stipulates that for So what shall the software engineer go with?
If these two normative documents allow the engineer to make either choice then he should be ultimately fine with any of those. In fact, precisely because of this, the DIX Ethernet format has become the de facto standard for most deployments whatsoever.
The fact that you still see the So, to sum this up, what frame format is going to be used depends on the software at this level, usually a driver or an extremely low level system service that asks the network card driver to transmit some data.
The particular choice is usually decided by the author of the software. We could go into technical advantages and disadvantages of every frame format - something we have not covered yet in our discussion here - which are driving the software engineers choice, but in general, the Ethernet II DIX , or in some cases, the SNAP are the ways to go, and Ethernet II is by far the most popular.
It definitely makes more sense to me know. If you don't mind i would like to ask few more questions to get a better idea. Is the IP driver representing somehow the higher layer? And also do you mean that it communicates with the network driver that i communicates with the LLC Sublayer?
In general, sorting protocols into layers is sometimes a reason to start a flamewar, as our protocols are not created strictly according to the OSI model and so they often do not fit perfectly :. Yes, the IP driver is an embodiment, or an implementation, of a particular Layer3 functionality. You see, a protocol on a certain OSI layer is just a set of rules, but it needs to be implemented, written as a software code or constructed as a hardware, in order to start to really exist.
And yes, when the IP driver needs to send or receive its packets over an Ethernet card, it can be assumed to communicate with the LLC sublayer implementation in the Ethernet card driver. Which Data Link Sublayer is responsible for framing? So i would say that it's the MAC's sublayer job. Very good! It is that, and even more.
Notice how crude this is: No information about what the Message really is, no connection-oriented communication, no reliability, no ordered delivery, no acknowledgements, no retransmissions, no flow control. All these features - if present - are implemented by the LLC sublayer:. The truth is, Ethernet can be connection-oriented and reliable if software engineers want it to! The most commonly seen function of the LLC sublayer is identifying the payload type of the frame, so that a single Ethernet network can be used to carry multiple higher protocols at the same time and still processing each of them correctly.
Create a free Team What is Teams? Learn more. What is the difference between Ethernet II and Ask Question. Asked 7 years, 11 months ago. Active 7 years, 11 months ago. Viewed 26k times. Improve this question. MikePennington : Hi , I am not not taking regarding the packet format. I Just Want to know the theoritical explanation.
Daniel has a great write up here explaining the differences in detail: lostintransit.
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