John Harrington
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John Harrington
Four Trouble Ticket Survival Tips
Sometimes the phrase ‘working the ticket queue’ is code for ‘doing meaningless work’. If you find yourself playing whack-a-mole with your ticket queue, then this is the post for you. You should strive to do meaningful work and this post discusses … Continue reading
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3 Suggestions for Network Automation
Network automation is a hot topic right now. However, many of the automation solutions focus on edge-port provisioning. I can understand why vendors are chasing this niche; port-provisioning is a high-volume and error-prone activity. Network Automation Ideas Port provisioning isn’t the only … Continue reading
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Network config backups – just the beginning
An emergency switch replacement can ruin your day. However, having network config backups is not enough. Restoring full service may not be as easy as just copying the running configuration from your RANCID CVS repo, or your colleagues hard drive. Restoring the ‘identity’ … Continue reading
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My top five posts – Nov 2015
I’ve written quite a few posts on this blog, but admittedly I’ve slowed down a lot. I have plans to change that soon, but in the mean time I’ve compiled a quick run down of my top-five popular posts by … Continue reading
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What about software assisted networking?
I don’t want a software defined network, I want a software-assisted network. I want tools that will help prevent common but straightforward mistakes and make it easier to baseline a network. These tools have to work on real networks. Those messy, brownfield, imperfect … Continue reading
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Interface descriptions – your last hope
No, I’m not starting a naming war. Not really. I don’t care if you use ! or # or >> or {} to mark your interface descriptions. I don’t care if you use all-caps or lowercase, or if you feel … Continue reading
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The many ‘modes’ of multimode
Fiber types are differentiated as multimode or single mode. Single mode was always easy for me to understand but I could never quite understand what ‘multimode’ actually meant. I’m written some notes for myself on this topic that I thought I’d … Continue reading
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Packet pushers podcast – Hardware Resources
It’s been quite a while since I’ve posted here but I wanted to highlight some work I’ve been doing with Greg Ferro and Simon Chatterjee on the Packet Pushers podcast. We recorded a three part series where we dive deep … Continue reading
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Using IPMI Serial-over-LAN for server consoles
I’ve been trying to learn linux networking and virtualisation using a donated server in a remote lab. The server didn’t have an IP-KVM attached but it did have a working IPMI connection. Not that I’d need it of course; I … Continue reading
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Is CPU or ASIC responsible for forwarding?
I received the question below from reader Ned as a comment on my 24-port ASIC post and thought that the discussion was worth a post of it’s own. …Would you be able to speak a bit about the actual physical path … Continue reading
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Hardware – What’s the ‘holdup’?
This post discusses power supply ‘holdup’, and how it can impact network or server hardware uptime. The holdup time or ‘output holdup time’ is the length of time that a given power supply can maintain output power to the switch … Continue reading
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Planning projects instead of burning benjamins
Engineers are often unstuck by poor planning and get hit with large financial penalties as a result. Projects can become mired in delays and complications due to unforeseen costs and expenses. There are some unavoidable bumps in the road, but … Continue reading
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Hardware – Equalization and Pre-emphasis
Before we look at equalization and pre-emphasis, we should examine some fundamentals of waves and signals. A perfect square wave is a really useful way of representing a waveform in the time-domain, but it’s not the only way of looking at … Continue reading
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Hardware – Is SFP+ just a smaller version of XFP?
In the last post I discussed clock and data recovery (CDR). This post examines an application of re-timers (or CDRs) within XFP and SFP+ transceivers. I’ve previously covered the size, power and connector differences of 10G transceivers before, but this post will focus … Continue reading
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Hardware – Clock and Data Recovery
Clock and data recovery is an essential physical-layer function of modern switch and router hardware. Digging deep into the electronics of a router may not be your thing, but clock recovery is a fundamental building block for other network hardware … Continue reading
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Build a 48-port switch using a 24-port ASIC
Modern top-of-rack switches (or TORs) run at line rate and are non-oversubscribed. This means you get non-blocking [1] port-to-port throughput within the switch ASIC at the line rate of the front panel ports. Almost all TOR switches use a single switch … Continue reading
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AirConsole Review
If you need regular console port access then nothing beats a fixed console router. However there are many times when that simply isn’t an option. For occasional console connections I use a Keyspan USB/Serial adaptor with my MacBook. It’s … Continue reading
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Five selfish reasons to interview candidates
Lets be honest. It is hard to justify the time needed to interview people. It can be really hard to motivate yourself to interview potential new hires when project deadlines are looming. It is perfectly fair to ask yourself, “what’s in it for me?” I think there is a payoff for time spent on hiring. […]
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The post Five selfish reasons to interview candidates appeared first on Packet Pushers Podcast and was written by John Harrington.
Why ‘your’ project was outsourced
It’s easy to get upset when that cool new project you wanted is outsourced to an external VAR. The conversation usually goes something like, “You know the existing network and services really well so we’re going keep focused there. We’re going to engage ACME systems integrators for ‘project awesome’ and get them to give that […]
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The post Why ‘your’ project was outsourced appeared first on Packet Pushers Podcast and was written by John Harrington.
Flow
Have you ever struggled to explain to your parents or friends why you still study technical topics at night? It can be frustrating trying to explain to these people why you do what you do. Let’s be honest, it’s hard to explain ‘why’ to ourselves, never mind explain it to others. I have found a […]
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The post Flow appeared first on Packet Pushers Podcast and was written by John Harrington.