What is IP SLA (Internet Protocol Service Level Agreement) How to configure IP SLA?

 

IP SLA (Internet protocol service level agreement) is a great feature of the Cisco Internetwork Operating System (Cisco IOS). It is used to measure the ongoing behavior of the network. the measurement can be simple as using ping where we check the round-trip time or something more advanced like a VoIP RTP packet where we check the delay, and jitter and calculate a MOS score that gives you an indication of what the voice quality will be. IP SLA primarily acts as a tool and gathers data about a network.

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Linux IP Comand Reference Sheet

 

If you haven't checked it out, https://linuxopsys.com/ has tons of great Linux commands, tips and tricks.

Here is their IP Command Reference Sheet

iperf2 Bandwidth Option

 

Many of my regular readers have seen my videos and read my articles covering iperf and iperf3.

Well, last week I came across iperf2 https://sourceforge.net/projects/iperf2/ and it has some really cool features that are lacking in iperf3. For a detailed list go to https://iperf2.sourceforge.io/IperfCompare.html and of course there is a manual html page at https://iperf2.sourceforge.io/iperf-manpage.html

lastly, there is always the good old –-help (that’s a double dash) option to see all the options.

I thought I would focus on one of the options that I like , the bandwidth option -b which works with TCP and you can even combine it with the port option to change the default port number. You can also use kmgKMG or even pps (packets per second).

When i use -b, with iperf3 it doesnt work with anything less than 10M, so if I used -b 5 , it resulted in a 10 MB result

Enjoy folks

Weekend Flashback - The Conforama

 

The **Conforama computer** is one of those rare tech curiosities that perfectly captures the intersection of retail ambition and early home computing trends. Conforama, a French furniture and electronics retailer founded in 1967, wasn’t known for building computers—but during the 1980s and early 1990s, they briefly ventured into selling rebranded PCs under their own name. These machines were typically produced by OEM manufacturers and customized with the Conforama logo, targeting casual users and small businesses just beginning to explore the digital world. At the time, having a “Conforama Computer” was a mark of accessibility—it offered an affordable way for families to own a home computer without the premium price tags attached to brands like IBM or Compaq. One of the most interesting bits of trivia about Conforama computers is how they were marketed. Unlike traditional computer companies, Conforama sold theirs alongside sofas, lamps, and kitchen tables—essentially turning the act of buying a computer into a lifestyle choice rather than a technical decision. Ads from the era emphasized comfort and convenience rather than specs or performance. This unusual marketing approach made them memorable to French and European households that were taking their first steps into the PC revolution. Some models even came bundled with simple productivity software or early educational games, making them appealing for families with children. Today, original Conforama computers are rare collector’s items, not for their power or innovation, but for their place in retail and computing history. Enthusiasts who restore vintage hardware often seek them out for their unique branding and nostalgia value. It’s a quirky reminder of a time when nearly every retailer wanted to have a piece of the computer boom—even those better known for selling couches than keyboards. While Conforama has long since exited the computer market, its brief foray remains a fascinating footnote in the story of personal computing’s expansion into everyday life.

A Few Words About Nothing

 

If I told you that only 26% of the population can demonstrate a basic understanding of calculus, and 63% of those are women, you might be surprised.  It would appear that calculus must be a niche specialty where women are well ahead of men.  You could not help but wonder how men have dominated the STEM fields for so long, given this apparently superior mathematical aptitude that women have. 

 

The truth is, both men and women are equally capable of advanced mathematical reasoning, and the above statistics are fictitious.  It is a proven fact that we find statements accompanied by precise numbers far more compelling than vague assertions.  We trust statistics, with little regard for how they were obtained.  A cautionary view is often attributed to Mark Twain (who himself credited British Prime Minister Benjamin Disraeli) – “There are three kinds of lies; Lies, Damned Lies, and Statistics.”  Statisticians have a language all their own, which only makes things worse.

 

A statistician approaching the aforementioned question of mathematical acuity would begin with a test of some sort and form a hypothesis – something like “There is no difference in standardized mathematical test scores based on gender.”  In stat-speak, this is the “null hypothesis.”  If the data showed no difference in test scores based on gender, you might say men and women are equally proficient at math.  A statistician, with an apparent aversion to commitment, would only say their study “failed to reject the null hypothesis.”  If nothing else, reading this paragraph should convince you that Mark Twain was on to something.  

 

“Null” is a nothing word, something with no value.    It comes from the Latin “nullus”, meaning “not any.”  It has also come to mean “invalid” or “powerless.” In our math-gender example, it says, “Move along now – there’s nothing here.”  Although software developers may use nulls for padding or as delimiters, they otherwise have little value.  Nothing is nothing, after all.

 

It would be easy to conclude that this is much ado about nothing, but there is more to nothing than first appears.  If you’ve ever typed an address into Google Maps (e.g. 1600 Pennsylvania Avenue, Washington, DC), you would see a map with a pin at that location.  How does it know?  Thanks to geocoding, the physical addresses with which we are familiar have been converted into coordinates that the map understands – in this case 38°53'52.2"N 77°02'11.7"W.  This is a hidden marvel of modern technology, except when it’s not.

 

Geocoders are not perfect, nor are the humans who use them.  Mis-spelled street names, non-existent address numbers or just plain typos can confound the system and cause it to default to “0,0”.  This poses a bit of a problem in that 0,0 is an actual location on Earth, south of Ghana in the Gulf of Guinea.  It is a running joke among GIS professionals that all those mistakes are sent off to “Null Island.”  Ironically, Null Island is one of the most visited places on Earth, though it doesn’t actually exist.  (NOTE:  There is, however, a NOAA weather observation buoy, known as Station 13010, located at 0,0). 

 

Like many big cities, Los Angeles has some rough areas that tourists should avoid.  The section surrounding LA City Hall directly across the street from the Los Angeles Police Department would seem safe but in one 4-month period, it showed on the map as the location for 1,380 crimes. There is a hand-written entry for every reported crime in the city, and if the computer can’t decipher it, it defaults to the front of LAPD Headquarters.  Once this was discovered, the fix was clear – deport all those criminals to Null Island.

 

Typos and criminals aren’t the only things banished to Null Island.  A popular outdoor fitness tracking app called Strava, used by athletes to share their training feats on social media, incorporates GPS based location tracking to broadcast from where and for how far they ran, cycled, or swam.  When Strava published a "Global Heatmap" to hype the widespread usage of their product, some folks noticed a concentration of activity in a few unlikely areas.  When it was revealed that some of these were heretofore undisclosed military bases, privacy concerns arose, and people started entering “0,0” as their starting location.  Soon Null Island became a global destination for fitness training.

 

An outbreak of COVID19 cases, a scourge of cyberattacks, some crazy gender theories - all have helped Null Island maintain notoriety through the years as a busy yet non-existent place.  It will long endure as a gathering spot for a vast assortment of items with one thing in common – nothing.

 

 Author Profile - Paul W. Smith - leader, educator, technologist, writer - has a lifelong interest in the countless ways that technology changes the course of our journey through life.  In addition to being a regular contributor to NetworkDataPedia, he maintains the website Technology for the Journey and occasionally writes for Blogcritics.  Paul has over 40 years of experience in research and advanced development for companies ranging from small startups to industry leaders.  His other passion is teaching - he is a former Adjunct Professor of Mechanical Engineering at the Colorado School of Mines. Paul holds a doctorate in Applied Mechanics from the California Institute of Technology, as well as Bachelor’s and Master’s Degrees in Mechanical Engineering from the University of California, Santa Barbara.