Tech Notes: Difference Between OS1 and OS2 Fibre Optic Cable

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These are two standards for single mode fibre optic cabling from a total of  five types of fibre that are generically used today known of “OF types” (OM1, OM2, OM3 for multimode and OS1,OS2 for single mode.) OS1 is for indoor use  i.e. Campus, Data Centre. Cabling is is tight buffered (i.e. manufactured into solid […]

Tech Notes: Ping Sweep an IP Subnet

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This is my current goto code snippet for using the BASH command line to perform a ping sweep through an IPv4 subnet. for i in `seq 1 255`; do ping -c 1 192.168.1.$i | tr \\n ‘ ‘ | awk ‘/1 received/ {print $2}'; done This script is deliberately simple, only works for /24 subnets but […]

Visual Guide to LAG Thinking for Server Admins

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When working with Server and VMware people, there is a fair amount of misunderstanding of what is happening in the network. The best technical explanation for what is happening in LAG is, of course described at Ivan Pepelnjak’s IPSpace Blog – vSphere Does Not Need LAG Bandaids – The Network Does while Chris Wahl talks about the server side for VMware but I wanted to add something to the debate.

◎ Tech Notes: Arista AgilePorts – Building 40Gigabit DCI with 10GbE ports

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Stumbled over “AgilePorts” feature in Arista products this week: Arista’s AgilePorts technology enables the combination of four 10GbE SFP+ interfaces into a single 40GbE interface leveraging the parallel lane technology present in the 40GBASE-CR4 and 40GBASE-SR4standards. With AgilePorts, each 10GbE interface emulates one of the four parallel lanes, which are then driven by a 40GbE […]

Basics: Three Types of Cisco UCS Network Adapters

In the Cisco UCS servers, there are three classes or categories of Network Adapters for B-series and C-Server servers. I write this down because it’s pretty hard to find this summary anywhere is Cisco’s documentation and I keep having to tell people the difference. Now I can point them at this blog post.