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Home > Archive > CCNA > September 2002 > SAP and SNAP
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| Hi everyone,
I am really confuse on the differance between snap and sap in the LLC header. Can someone please let me know what each of these do and give an example of each.
Thank you | |
| kphua 2002-09-26, 12:47 am |
| Okay, let me try to clear the air here (please correct me anyone if I'm wrong  )
The LLC header (3 bytes) contains two Link Service Access Point (LSAP) fields (DSAP, SSAP and Control) to identify the protocol of the data that follows it (e.g. DSAP=0xE0 means the next header is a Novell IPX header).
However, since the DSAP is only a 1-byte field, there weren't enough IDs to go around, so the IEEE decided to add the SNAP header after the LLC header. So when DSP=0xAA, it means that a SNAP header follows it.
The SNAP header (8 bytes) contains a 2-byte protocol type field (the EtherType field), which identifies the protocol of the data following it, e.g. A value of 0x0800 means that the next header is an IP header.
If you're interested, you can lookup the rfc for the SNAP EtherType numbers at:
http://www.isi.edu/in-notes/rfc1700.txt
quote:
Originally posted by Manjo
Hi everyone,
I am really confuse on the differance between snap and sap in the LLC header. Can someone please let me know what each of these do and give an example of each.
Thank you
| |
| edmonds_robert 2002-09-27, 2:50 pm |
| I don't mean to get off the subject, but KPHUA, you have given me a new favorite quote:
"Try not. Do, or do not. There is no try!" - Yoda.
Mind if I steal that? | |
| Johnno 2002-09-27, 7:51 pm |
| ...shot out.
You are the man kphua!
Tell me. What is the work situation like in Singapore for network people. I have been there a few times and like it there.
Just curious.  | |
|
| Hey, be my guest...I didn't think that one up myself anyway
May the force be with you.
quote:
Originally posted by edmonds_robert
I don't mean to get off the subject, but KPHUA, you have given me a new favorite quote:
"Try not. Do, or do not. There is no try!" - Yoda.
Mind if I steal that?
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