Tag: network analysis

Not all network engineers understand the impact of interface errors on TCP performance. Interface errors can cause a BIG impact, although it may not be intuitive at first glance. We recently pointed out some interfaces with extremely high errors to a customer. We mentioned that the links with the highest…

In my last post, Wikipedia on Transmission Control Protocol). A packet is assumed to be lost when an ACK has not been received within 2 * RTT. So network buffering [...]

I’ve been doing a number of network assessments recently and one of the factors that I use to determine network health is the number of TCP retransmissions that occur. I [...]

In A Network Management Architecture, Part 1, I discussed a Network Management Architecture, composed of seven elements, shown in the figure below. I described the Event and NCCM elements in [...]

I just returned from a week at CiscoLive 2011. The show floor had a lot of network management products on display, making it an easy place to walk around and [...]

Several of us at TCP Performance and the Mathis Equation for calculating TCP performance due to packet loss.) UDP applications wouldn’t have any feedback and would continue to monopolize the [...]

I’m helping a customer improve their network through better network management visibility into network problems. The result of a proof-of-concept is this graph, which I’ll explain below. The customer loved [...]

I just finished spending two days in San Jose, participating in the Gestalt IT Network Field Day, an event dreamed up by Stephen Foskett and Greg Ferro. Twelve delegates who [...]

I’ve been doing Data Center design recently and the customers are interested in what to monitor and why it should be monitored. At first, a data center is just another [...]

I’ve written in this blog about various reasons for using network automation but it is time to put them together. Counting down… 7. Performance and SLAs The first thing that [...]

I’m a proponent of network management automation and found a related blog post, Arno Penzias, former Vice President and Chief Scientist of Bell Laboratories, and a Nobel Laureate in Applied [...]

Because NetCraftsmen was offering a free 30 dial trial of Netcordia’s NetMRI software, we have had some recent discussions on the best way to run a trial. Here is my summary [...]