mitzy miroy wrote: > > Hello all, > > Excuse me in advance if these questions are rather elementary > in nature, but I'm getting frustrated at some contradictions I > am seeing while studying for the CID exam. > > 1. Should access lists be placed at the distribution or access > layer in a hierarchical topology? I realize it depends on the > purpose, but I've got a Sybex book that says that for the sake > of the CID exam, they go at the access layer, while everything > else says to place them, generally speaking, at the > distribution layer. Why would the general recommendation be > different for the CID, or is it?
I don't think CID disagrees with other tests on this. Access lists, generally speaking as you say, belong at the distribution layer. I checked the official Cisco Press CID book and a couple other books, including my book, Top-Down Network Design. I don't know where the Sybex authors got the impression that CID doesn't agree with other tests on this. > > 2. In an ATM LANE newtwork, is it the LEC or LES that performs > address resolution from ATM to MAC addresses? I'm seeing that > both devices perform the address resolution and figure it must > only be one of them, which one is that? A LEC is a LAN Emulation Client. It's the one that knows that address resolution is necessary because it has some data to send on behalf of an upper layer, just like a normal client workstation would on Ethernet. However, unlike Ethernet, ATM is a non-broadcast multiaccess network, so the client can't do the resolution on its own. A LEC registers its own MAC address with a LAN Emulation Server (LES). In addition, a LEC queries its LES when it needs to resolve a MAC address to an ATM address. The LES responds directly to the LEC or may forward the query to other clients to let them respond. > > 3. Are 'secondaries' and 'subinterfaces' synonymous? They're > two separate entities in the materials I'm reading, but they > seem to point to the same thing? No, secondaries and subinterfaces are not synonymous, although they may be used to solve similar problems. This is something you will want to learn about for all exams. Check CCO documentation for more details. In general terms, secondary addressing is usually avoided these days. Subinterfaces are considered better. In the past subinterfaces were much more common on WANs, while secondary addressing was more often used on LANs. That's no longer true. So in the design reading material, you may be running into problems with legacy methods being described instead of newer methods. I hope this helps. Good luck with your CCDP! Priscilla Oppenheimer http://www.priscilla.com > > I just want to make sure that I answer these questions > correctly should they come up on the exam. > > Thanks in advance, this list is great! > > :-) mitzy Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=51112&t=51105 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
