All about networks

  • 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 cause of heartache in networking. In this post I’ve shared a few painful problems that the…

  • 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’ of your original switch is a multi-step and somewhat complicated process.

  • 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 page view. Once you’re finished reading the links please read on to my question below.…

  • 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 networks that everyone maintains, but not everyone admits to owning. I’ve listed five tools below that…

  • 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 a fundamentalist zeal about other punctuation. I want to brave the flames of a naming war to…

  • 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 share. I’m sure some physicists will have an allergic reaction to my take, but I’m happy…

  • 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 into the guts of networking hardware. All three shows are now published on the packet…

  • 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 was experimenting with network settings whilst ssh’d into a server that was four and a…

  • 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 or packet flow a packet takes inside the switch itself and how does the hardware…

  • 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 or server after it’s input power supply has been cut. The dependent host will shut…

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