Cisco Cisco Cisco

With many Cisco projects on the go, the office has become an obstacle course of firewalls, switches, routers and network cables. As various engineers tripped over the kit, they’ve been asking, why Cisco? How do I even begin to configure these alien non-user interface devices? Why would I want to?

So here is my very brief introduction to Cisco, which is basically a list of useful websites, PDFs and some key Cisco commands.

Useful Cisco Resources

1. OSI Table – Something you’re often taught at college or university, is the OSI network model. You then you get a job in IT and forget all about it! Its good idea to re-visit the model, as it will with some of the Cisco concepts.
   
   You can download the full PDF from theCisco website
2. Packet Life – Cheatsheets – Packet Life has an excellent selection of Cisco related one-page cheatsheets.
3. Dans Courses – If you instead start with a more structured journey with Cisco, then look at Dans free online courses
4. CBT Nuggets – Same as above but a paid service.
5. IP Calculator – Keeps me right when working out subnets and configuring new networks
6. Packet Tracer – Software Defined Networking, this is one you’re going to hear more and more about. This free tool from Cisco
7. Ioscheat.php – Another cheatsheet

Cisco Commands

1.  Show me the money interfaces – Displays the status of each network interface on switch/router/asa

   1. switch# show ip interface brief
      

2. Type of Cisco – Tells you the basics about your device, including serial numbers and if the devices are stacked.

   1. switch# show version
      

3. Who lives next door? – If your Cisco devices are physically connected but are not configured to talk to one another on the Network Layer, i.e. same subnet, then this command can show you connected devices.

   1. switch# show cdp neighbour
      

   2. switch# show cdp neighbour detail
      

References

• Catalyst 3750 Switch Stack
• OSI Model Reference Chart