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Cisco Skills

HDLC vs. PPP

HDLC and PPP are considered to be in layer 2 of the OSI model. There are some differences between which will be describe in this post, If you would like to learn more about at least the basic configuration of PPP including PAP and CHAP check out the post I wrote about year ago.

Configure Router on a Stick

A while ago I talked about putting different VLANs on a switch, remember a VLAN is virtual network that although physically it may look like on the same network that does not always mean the case. By having VLANs you are segmenting the network and the only way to get to the other side is having a router. I have already configured the Cisco switch as posted in Creating VLANs but in summary I have three VLANs total VLAN 1 which is the native VLAN, VLAN 2 and VLAN 3 (which is called support. If you like to understand how create VLANs on a switch follow the post above. If you look at the network topology below you can see where Cisco came up with the name "Router on Stick" each PC is on its own network and needs the router in order for traffic to pass between the networks. Like before I have three VLANs total. VLAN 1 which is the native VLAN, VLAN 2 and VLAN 3 (which is called "Support").

The Three Tiers

Working towards the CCNA Cisco talks about a hierarchical network there are three layers to this design. Access Layer, distribution layer and the core layer. Each of them have their own set of functions and is also considered to be a best practice when the network continues to grow and for redundancy along with just a better way to manage it.

Color Code Your Routers

I came across an interesting idea, what if you could color code your devices in command line? So such as if you were operating routers at a core level you could color code the CLI to the color red, and the branch routers green and etc. I wasn't sure if this would possible but doing some searching through the internet I found a guy Ivan Pepelnjak who wrote how to do this a couple years ago and wrote a couple books as well, check out his blog/website at http://www.ipspace.net there is tons of helpful information along with his original guide here.

Network Troubleshooting

The thing that makes networks awesome is the fact that once you setup a network you're not done. That may sound like a drawback but it is excellent job security! Engineers or administrators must watch the performance of an organization's network to make sure that productivity is not affected. Network outages can have a huge effect on an organization, lost revenue and the cost of unproductive employees can severely damage the organization, Earlier this year I also talked about the troubleshooting process which goes hand in hand with network troubleshooting. One of the major things a network engineer or administrator needs to have is documentation of the network.

How to Configure SSH on Dell Power-Connect

Although not dealing with Cisco directly Dell switches are around in network closets and with my limited experience with them I thought this would be a perfect blog post to show the differences between Dell and Cisco. I like to think of Dell CLI like a dumb downed version of the Cisco CLI so I had some time to play around with a Dell 6248P switch and wanted to figure out how to get SSH working in the thing. Couple searches around the web and some guess and check methods I was able to get SSH working and disable telnet sessions from connecting to the switch. Compared to a Cisco switch dell has few commands when configuring SSH. This switch was configured with an IP address and user name and passwords before I touched it but I don't think would too hard to figure out. :)