Archive for March, 2012

Coding a XenServer Client in Python – Monitoring Multiple VMs via Multiple Threads

Friday, March 30th, 2012

HueXenClient - XenServer client written in Python using the Citrix XenAPI

HueXenClient - XenServer client written in Python using the Citrix XenAPI

In some prior blogs I had written about developing an ESXi client in Java which could connect to a VMware ESXi server and perform some management tasks. In this blog, I will describe developing a Cirtrix XenServer Client in Python that connects to a Citrix XenServer or XenServer pool; the client can also perform management tasks and provides some advanced monitoring features. (more…)


EIGRP – Best Path Selection

Tuesday, March 27th, 2012

By 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. (more…)


Setting-up Basic iBGP and eBGP on Cisco Routers

Thursday, March 15th, 2012

The 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. (more…)


Single/Dual and Multihomed Connections

Monday, March 12th, 2012

Network 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)