If you have trouble acquiring routers and switches, you can use Dynamips/GNS3, where you take actual Cisco IOSes and they are run as a VM, its own separate instance. You can then build graphical network topologies. IMO its probably the best network sim out there since you're using actual IOS.
It is not an out-of-the-box ready to use simulator like Packet Tracer is, but its night and day better. You can even simulate your own internet connection with it. Its basically running the real IOS, just not on a bunch of routers/switches.
I liked Packet Tracer for a short while until I got fed-up with its many bugs (especially with STP to RSTP convergence, EIGRP UEC Load balancing simulation, or the limits when writing ACLs and NAT statements.), and it's technical inaccuracies. And it just plain crashing.
Its a program not running any kind virtualization with the real thing, rather it uses methodical IOS.
However its more fun to use the real thing, and you start to build a cognitive understanding of how the hardware is supposed to respond, learn it's limits, and features you do not find from virualization.
MY current setup at home are:
2x 2950-24 catalysts
1x Catalyst 3550
Usually if you're going with hardware, the best and most recommended setup is to get three routers and 3 switches. This way you can learn the ins and outs of STP, (root concepts) And you can play with NAT statements and ACLs all day long and run debugs for just about every kind of protocol/process and not have a boss that wants to cut your heart out with a butcher knife. You can also learn what kind of overhead protocols have, which one uses less, which one uses more, and learn what effect they will have on the hardware. You can also mess with SSH/TFTP completely barebone your router, etc.
Resources I have found great for CCNA and up:
Jeremy Ciora's CBT Nuggets videos
Train Signal with Chris Bryant
Todd Lammle's Sybex CCNA Guides
The Basic Cisco Press ICND 1 and 2 books.
- Where you will find all kinds of Cisco gurus that will basically smash your confidence in what you know about Cisco. - They also have a lot of great resources too. Professional blogs, as well as one of the greatest pages for practicing subnetting: http://networking-forum.com/practicesubnetting.php#
and a work in progress great test-practice. You will find gurus there that at the drop of the hat will be able to explain things Cisco as though it's their second nature.
- great place for Cisco Labs, and free too.
- omg, the amount of knowledge, you'll need a second brain for this one.
- soo much Cisco stuff here.
And finally, where all the purposes of the Cisco world is officially documented and explained, Cisco itself: www.Cisco.com
All in all, study it balls to the wall, and when you think you're ready for your CCNA, you are usually mistaken. It not only tests your theoretical knowledge, they will usually make the simplest things difficult. And a big portion of it is to know your IOS. The question mark in the IOS is very helpful, but only to a certain degree. There are no trick questions on the test, the question are straightforward, what makes them hard is detail. You need to think like a network engineer, and be able to think 10 steps ahead of cause and effect problems.
When going for Cisco certs, its not like a bunch of lower certifications where its just memorizing terms and standards and understanding a few concepts. You have to either know your stuff or you don't. There is no in between.
Its not your 10th Grade Algebra test, its a big metal shovel you put your brain on and if its not heavy enough, it will be tossed around and chewed up by a rabid pack of wild animals Edited by Kaiga - 7/28/11 at 1:24pm