Troubleshooting: ICMP Host Unreachable

By | Network Engineering, Troubleshooting, Uncategorized | No Comments

This article has two messages to deliver. The first being the technical piece where I review what the ICMP message means and what we tried to resolve the issue.  The second is to illustrate the methodology used. I wanted to make those statements because in the past, some readers tend to concentrate too much on the technical information and gloss over the methodology part of the article. Read More

Detecting Network Problems Before Users Do

By | Network Engineering, Network Monitoring, Troubleshooting | No Comments

In a perfect world, telecommunication networks have 100% uptime, low latency, and high bandwidth. In reality, each one of us deals with slow applications, choppy calls, and unreliable connections. In WiFi networks, this is even more frequent.

Yet, providing a good end-user experience is possible. Detecting problems before users do is not a fortune teller’s trick, but something that can be achieved with the right tools and processes in place. So how can Network Engineers achieve Zen for their networks? Read More

iPerf Performance Testing on Single Board Computers

By | Network Engineering, Network Monitoring, Troubleshooting | No Comments

I have done iPerf performance comparisons in the past between several well known single board computers (SBCs), which you can see here, and more recently, here. The most popular SBC is the Raspberry Pi, but its limitation is that it has a 10/100 interface, and the maximum traffic it can push is about 95 Mbps. The SBCs with gigabit interfaces I tested in the past, Odroid C1+, Banana Pi, Utilite Standard, couldn’t achieve 1 Gbps as receivers or transmitters of iPerf traffic. Recently, I came across the Odroid C2 and Up Board, which can achieve 1 Gbps iPerf bandwidth in both directions. Read More

How do you support employees working from home?

By | Network Monitoring, Product, Troubleshooting | No Comments

Working from home has its pros and cons. One of the negatives is that technical support is much more difficult. Employees working from home use their own local ISPs and each one of them uses a different modem. Chances are that they use a wireless router, which could be provided by the ISP or installed independently. Most likely, the employees need to use tools like Salesforce and Office 365, or custom applications that run either in the cloud or in a private datacenter.

When home-based employees can’t access the tools they need or experience “slowness”, they are quick to open a ticket with technical support. The environmental variables mentioned above make troubleshooting difficult. The main problem is the lack of visibility in the employee’s home environment. You will either guide the employee to run some tests for them (e.g. ping, traceroute) and email them the results back (if possible), or do a remote desktop session to begin troubleshooting.
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Is it the wireless, the wired network… or something else causing this latency increase?

By | Distributed network monitoring, Network Engineering, Network Monitoring, Troubleshooting | No Comments

NetBeez captures network and application performance from the user perspective on wired and wireless networks. Sensors at each network location run tests and simulate the user experience. We have dozens of demo NetBeez agents deployed around the country and the world and we collect some interesting data. Here is what I discovered recently while troubleshooting a NetBeez alert.

A typical NetBeez setup has a pair of agents, one wired and one wireless, at each office in order to capture the performance of both networks. Read More

Remote WiFi Packet Capturing with HORST on Raspberry Pi and Odroid

By | Network Monitoring, Troubleshooting, Wireless monitoring | No Comments

The Highly Optimized Radio Scanning Tool (HORST) is a lightweight IEEE802.11 WLAN analyzer. It was built for troubleshooting WLAN networks, and although it’s not as advanced as other tools (Kismet, Wireshark, tcpdump) it’s very easy to use, free, and can run very efficiently even on a Raspberry Pi.

For the installation and usage details, please see HORST on GitHub.

If you attended WLPC 2017, you have an Odroid that has HORST preinstalled and a USB WiFi Module. (Thanks to WLPC and Jerry Olla for the excellent Maker Session!) You are ready to run HORST! Just log in and type horst. In general, you should be able to install HORST on any Linux Single Board Computer (SBC). Read More

Network Performance Baselining with SpeedTest and Iperf

By | Network Engineering, Network Monitoring, Troubleshooting | No Comments

Ookla SpeedTest and Iperf are two very useful utilities for testing your pipes in terms of how much bandwidth they can pass. Their feature lists overlap, but there are also some differences. You are can read this post for a complete rundown on them, but in a nutshell:

SpeedTest: pushes traffic to an Internet server and measures latency, and upload and download speed.

Iperf: pushes TCP or UDP traffic between two hosts under your management and can measure bandwidth, jitter, and packet loss. Mostly used in WAN testing.

Through my discussions with fellow network engineers, I have learned that SpeedTest and Iperf are used in two main cases: Read More

How do you support employees working from home?

By | Distributed network monitoring, End user monitoring, Troubleshooting | No Comments

CxEwrL8UsAAvMNwSupporting people who work from home is something I can relate to since I’ve been one of those employees for more than a year now. I work from my home in San Jose, CA and the rest of the NetBeez team is in Pittsburgh, PA. Being a technical person, I am my own IT support. In addition, the Pittsburgh office has technical people, so if something comes up it’s easy to communicate the problem and troubleshoot it. But not everyone is as lucky. Read More

Network Controllability and Visibility

By | End user monitoring, Network Engineering, Network Monitoring, Troubleshooting | No Comments

dilbertWe are moving past the era of needing dedicated circuits for enterprise WAN networks. Connectivity is becoming a commodity, and since many applications run on the cloud or rely on access to the cloud, we don’t need private circuits to reach them. WAN connectivity is becoming commoditized and this creates new controllability and visibility challenges for network engineers.

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Troubleshooting network problems

By | Troubleshooting | One Comment

its-not-the-networkYou might not know it, but you don’t need to be a network engineer to perform basic network troubleshooting. Working as a network engineer for many years made me realize how many problems could be addressed by regular users without need to call the help desk or open a ticket.

To back my claim, here is a simple step-by-step procedure that you can follow to determine whether the problem you’ve encountered is caused by your laptop, the network, or the application you’re trying to access. Based on this information, you can easily figure out what needs to be done, saving yourself time and frustration.
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