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<DIV><FONT face=Arial size=2>Hello Heath</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]>
<DIV>> if I understand correctly TCP/IP has four layers that kind of
match up to layers 2-7 of the OSI model. The relationship to the physical layer
is that layers 2-7 of the OSI and 1-4 of TCP/IP relate to the physical layer in
</DIV>
<DIV>>the same way. Sound correct??? This leads me to the question of why
doesn’t TCP/IP have an additional physical layer at the
bottom??<o:p></o:p></DIV>
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<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> <FONT
face=Arial size=2>It sort of does and it doesn't. Apprently there is some
contention about how to map TCP/IP onto OSI. As far as I can make out
that's because the bottom layer of TCP/IP ('link' layer?) basically specifies
how TCP/IP hooks into another standard, for example, ethernet. Ethernet
itself incorporates the physical and data link layers, so in effect TCP/IP gets
two for the price of one. But technically, within itself TCP/IP does
not address physical layer issues at all.</FONT></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Calibri','sans-serif'"><o:p><FONT
face=Arial size=2></FONT><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]><![if !supportLists]><![endif]></o:p></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Calibri','sans-serif'"><o:p><FONT
face=Arial size=2>Regards</FONT></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Calibri','sans-serif'"><o:p><FONT
face=Arial size=2>Robert T-A</FONT></o:p></SPAN></P></BODY></HTML>