OSI Archives

Home » OSI

Using the OSI model to troubleshoot video

Dave Farquhar Hardware, Troubleshooting April 30, 2015November 28, 2016amd, nvidia, OSI, osi model, PNY

I was at church on Sunday and the video projection wasn’t working. After a few minutes of watching everyone struggle, I volunteered to take a look, and working together, we were able to get the video working again using a simple, repeatable methodology: Using the OSI model to troubleshoot video.

I’m going to share that methodology now.

Dave Farquhar

David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.

dfarq.homeip.net

Troubleshooting at all layers of the OSI model

Dave Farquhar security, War Stories April 15, 2013April 14, 2013ARP, job description, link speed, network cables, OSI, osi model, trenches, troubleshooting, UDP

I saw this phrase in a job description last week: Troubleshooting at all layers of the OSI model. That sounds a bit intimidating, right?

Maybe at first. But let’s not overcomplicate it. Once you get past the terminology, it’s a logical way to locate and fix problems. Chances are you already do most of this whether you realize it or not. I was already troubleshooting at at least four of the seven layers when I was working as a part-time desktop support technician in college in 1995.

Dave Farquhar

dfarq.homeip.net

One road to the CISSP: Do SSCP first

Dave Farquhar security June 10, 2012November 26, 2015CBK, CERT, cissp, isc, LinkedIn, OSI, osi model, SSCP

As my crazy week wound down, I had a number of visitors, including someone who’s been on the fence about taking the CISSP. She wanted some advice. The (ISC)² Code of Ethics says to give generously of such things when asked, so we talked for about 30 minutes. Read more

Dave Farquhar

dfarq.homeip.net

How to pass CISSP: Test taking strategies

Dave Farquhar security February 26, 2012September 28, 2016cissp, isc, ISO, OSI, osi model

The CISSP is a 250-question, multiple-choice test. You have six hours to complete it. It’s not like any college final I ever took, though cramming all of finals week into a six-hour session is almost a fair comparison. If you’re wondering how to pass CISSP, I can’t guarantee my method, but I’m glad to share what worked for me.

Dave Farquhar

dfarq.homeip.net

CISSP melted my brain

Dave Farquhar security January 28, 2012December 5, 2015cissp, OSI, osi model, UDP

Five and a half hours ago, I turned in my test and departed the CISSP test site. It took me four hours to answer the nastiest 250 test questions I’ve ever seen in my life.

I felt better about it than the other guys milling around the lobby, but….

Dave Farquhar

dfarq.homeip.net