Confusion between Ethernet, MAC, and data link layer

roghan

I'm studying for CCNA by one week, and in particular I'm in Chapter 1 (Introduction to networking basics). I understood that each layer has its protocols: Application-HTTP/FTP/..., Presentation-SSL/...,... However, I have a bit confusion about Ethernet and MAC :. MAC is a sub-layer of Data link layer (together LLC), ok, but is it even a protocol, right? Instead what is Ethernet?? A protocol? Another sub-layer?

thanks

capitanuionut

roghan wrote: »

I'm studying for CCNA by one week, and in particular I'm in Chapter 1 (Introduction to networking basics). I understood that each layer has its protocols: Application-HTTP/FTP/..., Presentation-SSL/...,... However, I have a bit confusion about Ethernet and MAC :. MAC is a sub-layer of Data link layer (together LLC), ok, but is it even a protocol, right? Instead what is Ethernet?? A protocol? Another sub-layer?

thanks

Ethernet is a standard. It defines :
- the pshysical cables for connecting equipment at physical layer.
- how frames are encapsulated at Layer 2.
- how different equipments have access to the network (CSMA/CD). -

The OSI model is a reference/theoretical model on wich all these standards and protocols have been created, it's not something like a protocol wich has it's rules and all that.
I'm not sure i was very clear but i hope i helped.

thedrama

roghan wrote: »

I'm studying for CCNA by one week, and in particular I'm in Chapter 1 (Introduction to networking basics). I understood that each layer has its protocols: Application-HTTP/FTP/..., Presentation-SSL/...,... However, I have a bit confusion about Ethernet and MAC :. MAC is a sub-layer of Data link layer (together LLC), ok, but is it even a protocol, right? Instead what is Ethernet?? A protocol? Another sub-layer?

thanks

Yeah, Ethernet is a standard which uses both physical layer and data-link layer to operate. It defines a communication between hosts which reside on the same link and sharing that link. Nowadays, Ethernet is known as the only LAN standard because token ring and others are not found attractive.

MAC is the media access control address as the name suggests which allows your computer to communicate on the LAN. Moreover, it provides access to
media such as cables or wireless media. This address makes your machine
unique and identifiable on the LAN. Without MAC addresses your packet
will never be prepared to be transmitted hence packets must track
all OSI layers from top to down and they have to be released to the media
"physically." while IP addresses are not physical but logical.

roghan

Thanks capitanuionut and thedrama . I think I understand what Ethernet is and the differences between Ethernet, MAC, data link and phisical layer. Hence, Ethernet is a standard for layer 2 and 1 that defines the communication process, while LLC and MAC are sub-layer for layer 2. Ok. The last question... What does IEEE 802.3 mean??? Is it referred to Ethernet standard?

okplaya

roghan wrote: »

The last question... What does IEEE 802.3 mean??? Is it referred to Ethernet standard?

Yes, 802.3 is the IEEE standard specification for ethernet. You have 802.3u, 802.3z, etc. Most standards have some sort of reference, but with 802.3 in particular, we commonly use 'FastEthenernet, GigabitEthernet', and so forth.

Notice for WLAN standards we use the actual IEEE specification (802.11a/b/g/n) instead of a regular name such as "FastWireless, SuperFastWireless, etc"

HTH

capitanuionut

okplaya wrote: »

"FastWireless, SuperFastWireless, etc"

HTH

You made my smile... but if this standards were called like this i think it would be easier to remember the differences between them and all that...at least with Ethernet it's clear from name that FastEthernet is better:Dafter that you only need to remember why it is.