Appletalk address

jheal00

I took the Network+ practice exam from this site and I'm confused about a question regarding Appletalk addresses. The correct answer to the question is "48.215" which is ok but I don't understand why 2 of the other choices are not ok. The other choices are "4E.215" and "48.2E5". I have read the Technotes on Appletalk but it is not clear to me why the above choices are incorrect.

Webmaster

AppleTalk adressesses are decimal, not hexadecimal. Since there's an "E" in "4E.215" and "48.2E5", they are incorrect. (Don't confuse it with a MAC/Ethernet address )

jheal00

I didn't see anything that stated it must be decimal and not hexadecimal (although I did conclude that after seeing the correct answer). My confusion seems to be coming from the fact that the technotes say the address is 24 bits (16 for the network and 8 for the node). Does that fact indicate the address must be decimal?

Webmaster

I didn't see anything that stated it must be decimal and not hexadecimal

I could have mentioned that in the notes indeed, but it doesn't say it must be hexadecimal either, so there's no reason to assume it is.

In my TechNotes I wrote:

The complete AppleTalk network address of node 37 is 58.37. The 16 bits network portion allows for 65000 networks and the 8 bits node portion allows for 254 hosts (0 can't be used, 255 is the broadcast address). The current version of AppleTalk is named AppleTalk phase 2, allowing multiple network numbers to be assigned to a single segment, known as an extended cable range, and eliminates the limit of 254 nodes per network. Sometimes the address includes the socket number, for example 58.37.254 or 58.37/254. An AppleTalk socket is similar to the concept of ports in TCP/IP.

8 bits allows for a maximum of 254, as mentioned 0 and 255 can't be used. 8 bits is 11111111 = 128+64+32+16+8+4+2+1 = 255. The number of bits, or the fact that the address is X bits long doesn't dictate that the address is uses a decimal or hexadecimal notation. An AppleTalk address just uses a decimal notation.

jheal00

Thanks for your fast replies. I needed to know if there was some way that I should have been able to deduce from the address length that it had to be decimal. Apparently not. However, now that I have taken the time to ask the question, it's unlikely I will ever forget that Appletalk addresses are decimal. I guess I am a little nervous because on Friday I bought an early expiration voucher for the Network+ test for $129 and I have to take the test tomorrow. Thanks again .. back to studying now.

Webmaster

You're welcome. Don't hesitate to post more questions if needed, and good luck on Friday!