From: Ivan (ivan@iip.net)
Date: Sun Feb 04 2007 - 16:31:32 ART
On Sunday 04 February 2007 21:42, Stefan Grey wrote:
> I just thought about following thing:
> 1) When we have two routers connected through serial connections and have
> set the encapsulation to ppp than PPP protocol works on the level 2 of OSI
> model and IP protocol works on level 3. So PPP does the LLC function of
> Layer 2. Correct??
>
> 2) Whe two routers are connected through simple ethernet link. Than IP
> still works on the layer 3. But I wonder which protocol would work on layer
> 2?? Which protocol woul provide LLC function??
Ethernet provide this function. Ethernet has MAC-address wich represent link
layer addresses. ARP used to define L3 to L2 mapping. Evolution of Ethernet
protocol begin from 802.3 standart. Later developers add 3 bytes LLC header
define destination/source service access point. More later developers see
that ip has code 0x8000, ipx - 0x8137, AppleTalk - 0x809b. All of this value
has two byte length and this can't conclude inside SSAP and DSAP. Therefore
they add another header SNAP(802.2). This header hold protocol of higher
level and standartisation organisation, only if LLC has 0xAAAA value.
>
> (I know that there would be Ethernet2 frame type but which protocol would
> work on the layer2??)
>
> Thanks a lot for clarificatation..
>
> _________________________________________________________________
> Customise your home page with RSS feeds at MSN Ireland! http://ie.msn.com/
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
-- Ivan
This archive was generated by hypermail 2.1.4 : Thu Mar 01 2007 - 07:38:46 ART