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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for your reply Robert,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Once again, different resources I look at give different layers to these devices. I like your version and I’ll run with it, accept I think the fact that NIC’s “transform” data to binary contributes to them being on layer 2. They are not just carrying data which I think is the sole role of layer 1. I’m not surprised or confused, I’m very accepting that that’s the way things will always be with SD. I just try and work out what level of understanding you need for the exam. Hopefully some trial questions will help us out soon. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As Mark mentioned recently, I’ve found that sometimes the less you know about the technical detail of topics in this course the easier it is to dumb down for the students. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regarding the network diagrams in the first outcome, since Paula suggested we could teach network topologies I am certainly going to cover network diagrams at the same time. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks again for the info.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Heath Matheson<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> sofdev-bounces@edulists.com.au [mailto:sofdev-bounces@edulists.com.au] <b>On Behalf Of </b>Timmer-Arends<br><b>Sent:</b> Monday, 14 March 2011 6:02 PM<br><b>To:</b> Year 12 Software Development Teachers' Mailing List<br><b>Subject:</b> Re: [Year 12 SofDev] Software development key knowledge<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt'>Hello again Heath</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>I didn't see the second question and since no one else appears to have responded (probably sensibly having a day off) I'll give it a go</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Question: Is it possible to classify switches hubs and NICs into the physical layer because they are hardware and the cables plug into them, while the data travelling through these devices is on an upper level? Or is a NIC always on the data layer and switches somewhere between data and network layers?</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>Switches hubs etc cannot be placed in the physical layer simply because they are hardware - afterall the computer we transmit messages from is also hardware. It depends on what protocol issues they have to deal with (possibly via firmware programming). So</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>- hubs are purely layer 1 since all they do is send a received signal to all ports - they in effect just repeat the signal, they have no understanding of the content of that signal</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>- switches need to know which port to send received data down so they need to know about physical addressing within a network which means being able to read data link (layer 2) frames</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>- routers need to know about the end to end addressing so they operate up to the network layer (3)</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>- NICs transform computer 1's and 0's into whatever the transmission medium requires so they are definitely layer 1. But it could depend on the kind of network they connect into; for example, collision detection in Ethernet is done in hardware on the NIC, but I'm pretty sure that collision detection (and then dealing with it) is a layer 2 function - I stand to be corrected on this. Also NICs are responsible for MAC addresses which is a layer 2 function. </span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>I hope this is helpful</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>Regards</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>Robert T-A</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'>Brighton SC</span><span style='font-family:"Times New Roman","serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> <o:p></o:p></span></p></div></div><p></p><p><b>Important - </b>This email and any attachments may be confidential. 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