Do you want Gonzo to post your real name?

gonzo · 03-20-2008

Quote:

Originally Posted by DannyCox

I guess your just going to stand behind your supposed single source of "proof" to back up your claim...the single source that you refuse to share. If what you say is so obviously true, you should easily be able to find reference to it all over the Internet and be able to post links to valid sites, like I did to refute your claims.

Yelling out "Page 280...Page 280...Page 280" on every one of your posts is just making you look foolish. As Ben Franklin said, "The definition of insanity is doing the same thing over and over and expecting different results."

It is time for you to give this up and concede you are wrong.

Here is the cut and past from page 280... drop your email in here if you want the pdf scan of the page.

I dont have FTP access currently to the Oprano server so I cant send it up.

--------------------------280-------------------------------------------

The most important distinction between these types of addresses is the distinction between
layers two and three themselves: layer two deals with directly-connected devices (on the
same network) while layer three deals with

indirectly-connected devices (as well as
directly-connected). Say, for example, you want to connect to the Web server at http://
www.tcpipguide.com. This is a web site that runs on a server that has an Ethernet card in it
for connecting it to its Internet service provider site. However, even if you know its MAC
address, you cannot use it to talk directly to this server using the Ethernet card in your
home PC, because the devices are on different networks.in fact, they may be on different
continents!
Instead, you communicate at layer three, using the Internet Protocol and higher layer
protocols such as TCP and HTTP. Your request is routed from your home machine, through
a sequence of routers, to the server at The TCP/IP Guide, and the response is routed back
to you. The communication is, logically, at layers three and above; you send the request not
to the MAC address of the server.s network card, but rather to the server.s IP address.
However, while we can virtually connect devices at layer three, these connections are
really conceptual only. When you send a request using IP, it is sent one hop at a time, from
one physical network to the next. At each of these hops, an actual transmission occurs at
the physical and data link layers. When your request is sent to your local router at layer
three, the actual request is encapsulated in a frame using whatever method you physically
connect to the router, and passed to it using the router's data link layer address. The same
happens for each subsequent step, until finally, the router nearest the destination sends to
the destination using its data link (MAC) address. This is illustrated in Figure 44.

Converting Layer Three Addresses to Layer Two: Address Resolution

The basic problem is that IP addresses are

too high level for the physical hardware on
networks to deal with; they don't understand what they are. When your request shows up at
the router that connects to The TCP/IP Guide, it can see the http://www.tcpipguide.com
server's IP address, but that isn't helpful: it needs to send to server's MAC address.
The identical issue exists even with communication between devices on a LAN. Even if the
Web server is sitting on the same desk as the client, the communication is logically at the IP
layer, but must also be accomplished at the data link layer. This means we need a way of
translating between the addresses at these two layers. This process is called address
resolution.

Key Concept:

Address resolution is required because internetworked devices
communicate logically using layer three addresses, but the actual transmissions