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bitsnake

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a fundamental conception

in a book about ccna:
Error detection does not imply recovery; most data links, including 802.5 Token Ring and 802.3
Ethernet, do not provide error recovery. In these two cases, however, there is an option in the
802.2 protocol, called LLC type 2, that does perform error recovery. SNA and NetBIOS are the
typical higher-layer protocols in use that request the services of LLC2.

i want to ask a series of question.
is ethernet including with LLC2?
commonly our lan uses ethernet or 802.3,LLC2 or LLC1?which relationship between ethernet and 802.3?LLC2 and LLC1?


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so does 802.2 consist of llc1 and llc2?
andre
thank you for you answer in detail.
could you tell me about something about llc1 and llc2?
thank you very much
Actually, 802.2 consists of LLC1, 2, and 3.

LLC1: Not connection oriented non-reliable. Example: IP and IPX.

LLC2: Connection oriented and Reliable. Example: SNA and NetBEUI

LLC3: Not conection oriented and Reliable. No example comes to mind (Sorry :-).

Remember I said 802.2 added a THREE byte header? Well, that's what the third byte is for.

Byte one: DSAP (Destination Service Access Point). Defines what protocol should decapsulate (don't know if word exists).

Byte two: SSAP (Source Service Access Point) Defines what protocol encapsulated.

Byte three: CTRL. The control field defines which LLC is used in that frame.

Got it?

Andre.

If you didn't get it, keep'em coming.