How Perl/Python Scripts on Force10 S60 Switches Can Access the Internet
Let’s say you have a Force10 S60 switch [FTOS 8.3.3.4] hooked-up at a datacenter that currently has a console connection connected to a management switch that provides external Internet access. The natted IP address is 10.0.8.10/24 and the external IP address is 209.37.21.20/24. Other than the console, the switch is only connected to a local network of other switches and servers. You are running some advanced python scripts natively on the S60 switch (yes, the Force10 S60 switch can run python and perl natively); however, the scripts you’ve written need access to the external Internet. What needs to be done?Setup OSPF on Force10 Switches
For this lab, I use a Force10 E1200 chassis [FTOS 8.3.1.1] and a Force10 S60 switch [FTOS 8.3.3.4]. The objective is to setup a simple OSPF network. Loopback addresses are used to setup test networks. Continue reading
Common Questions – What does 100 MB mean?
It’s one of those things that everyone knows and everyone asks. How big is 100 MB? This question is fundamentally flawed as the answer is in the question. So we should ask what does 100 MB mean? Well, to start with, a byte is a basic unit of measurement in computer science. A byte consists of 8 bits as a standard. A bit is the foundational unit of measurement in computer science and can only be one of two values – 0 or 1. It really represents one of two stable states of something such as the two positions of an electrical switch or two distinct voltage/current levels allowed by a circuit; you can also think of it as 1 = “on” and 0 = “off”. Continue reading
Symmetrical Multiprocessing in the Physical and Virtual World
The continuous shrinking of transistor size has pushed the limits of how many transistors can be placed on a single die (currently in the millions). In consequence, to utilize the increased amount of transistors, the CPU or “the core” has been replicated multiple times on the same die. Todays CPUs contain multiple cores with each core having fast L1 caches and sharing either a larger L2 or L3 cache, the bus interface, and the external die connections. For example, an Intel Xeon 7500 can support 8 sockets each with 8 cores for a total of 64 cores. Physical machines now commonly use multiple processors, but even in a multi-core processor, each core is treated as a seperate CPU. What this means is that even a multi-core CPU is taking advantage of symmetrical multiprocessing (SMP).Discovery Protocols on Cisco, HP, and Force10 Switches/Routers – CDP and LLDP
The Cisco Discovery Protocol (CDP) is a Cisco proprietary Data Link Layer network protocol used to share information about other directly connected Cisco equipment. CDP can also be used in place of dynamic routing protocols in simple networks. Cisco devices send CDP announcements out each connected network interface to the multicast destination address 01-00-0C-CC-CC-CC. By default CDP announcements are sent every 60 seconds. The “show cdp neighbors” command that you are probably familiar with basically displays stored information that has been collected from other devices. Further, the CDP data is also accessible via snmp. The holdtime, which specifies the lifetime of an entry in the table, by default is 180 seconds. Continue reading
Setup Inter-VLAN Communication via “Router on a Stick”
This lab demonstrates inter-VLAN communication via the “Router on a Stick” method. To enable inter-VLAN communication, a trunk link is created between a router and switch. Trunk links can carry traffic for multiple VLANS. Trunk links can also be used to span VLANs across multiple switches and allow them to communicate with each other. In general, communication between VLANs must go through a layer 3 device. Continue reading
How to sink your company with bugs, poor design, and poor support – SnagIt Case Study
TechSmith’s SnagIt is a popular screen/video capture software for Windows and Mac. It does get the job done most of the time, but these days, especially with basic screen and video capture, I expect much better. After having been forced to use this software because of limitations on what I have access to, I am surprised it is as popular as it is. I’m assuming most of those who use it are the “average Joes'” who know about it through word of mouth and its catchy, easy-to-remember name. I have used a number of screen capture utilities and, for Windows, would much rather prefer HyperSnap for screen capture and Camtasia Studio (also developed by TechSmith) for basic video capture . For Linux and Mac, I’d prefer the basic screen capture utilities that come with the OS. Camtasia Studio is also developed by TechSmith and is greatly superior to SnagIt, but it is also more expensive; I have not played with it extensively so cannot comment much more on it.
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