For easy reference, I’ve listed some important IPv6 address ranges below. Read the rest of this entry »
Important IPv6 Addresses
May 1st, 2012
Networking: Blocking Access to a Website via Extended Access List [Video]
April 16th, 2012This video demonstrates how to use an extended access list to prevent specific hosts from accessing a website. In this lab I use two Cisco 2811 routers [IOS 12.4(15)T1] and two Cisco 2950-24 switches [IOS 12.1(22)EA4]. Read the rest of this entry »
Networking: Spanning Tree Protocol Basics [Video]
April 15th, 2012This video covers some of the basics of how Spanning Tree Protocol (STP) works in a network. To learn more about Spanning Tree Protocol see some of my prior blogs on STP. Read the rest of this entry »
Algebra: Linear Equations (Coin Problem) [Video]
April 15th, 2012
I created and uploaded this video to youtube back in 2009. This video demonstates how to solve a simple algebra coin problem. Read the rest of this entry »
Chemistry: Calculate the Mass of an Atom [Video]
April 15th, 2012
I created and uploaded this video to youtube back in 2009. This video demonstrates how to solve a simple chemistry problem. I calculate the mass of a Chlorine atom. Read the rest of this entry »
Python – Implementing Caching in Your Applications via Dictionaries
April 6th, 2012
In this blog I demonstrate how you can implement and take advantage of caching in your Python scripts/applications.
Caching allows you to complete tasks more rapidly by storing and reusing results for repeated operations using the same criteria. For example, consider a function that takes several arguments and performs a complex calculation. What if you passed the same arguments to this function ten times; well, without caching, the same operation and complex calculation will be performed ten times. Read the rest of this entry »
Coding a XenServer Client in Python – Monitoring Multiple VMs via Multiple Threads
March 30th, 2012
HueXenClient - XenServer client written in Python using the Citrix XenAPI
EIGRP – Best Path Selection
March 27th, 2012By default EIGRP uses bandwidth and delay of the line to determine the best path to a remote network. However, if desired, EIGRP can use a composite of four metrics: bandwidth, delay, reliability, and load. Maximum transmission unit (MTU) is not used in EIGRP calculations but is a required parameter in some EIGRP-related commands. Also, by default, EIGRP will provide equal-cost load balancing across up to four links. You can disable load balancing by setting the ‘maximum-paths’ to ’1′. In this lab I use four Cisco 3725 routers [IOS 12.4(15)T10] to demonstrate EIGRP path selection behavior on Cisco routers. Read the rest of this entry »
Setting-up Basic iBGP and eBGP on Cisco Routers
March 15th, 2012The Border Gateway Protocol (BGP) is a protocol used to make core routing decisions on the Internet. BGP is commonly mislabeled or referred to as an IP routing protocol. However, it is not a routing protocol; rather, it is a TCP application that carries routing information with it. It is better referred to as a reach-ability protocol rather than a routing protocol. Read the rest of this entry »
Single/Dual and Multihomed Connections
March 12th, 2012Network engineers will sometimes speak of connections to their ISP(s) in terms of single homed, dual homed, single multihomed, and dual multihomed. Here is a breakdown and clarification of what this terminology means:
- Single Homed (1 link per ISP, 1 ISP)
- Dual Homed (2+ links per ISP, 1 ISP)
- Single Multihomed (1 link per ISP, 2+ ISPs)
- Dual Multihomed (2+ links per ISP, 2+ ISPs)