Have you every thought that you knew a topic pretty well but then someone uses terminology that you aren’t used to? People that use Cisco a lot or live outside the MEF world use another terminology than people that are working on MEF certified networks. Even if we both know the concepts, if we don’t speak a common language it will be difficult to communicate and to the the right end result.
When I took the CCDE written at Cisco Live, some of the QoS related material felt a bit off to me. I feel quite confident with QoS so this took me by surprise. My theory is that some of the material was written by someone coming from another background and uses some wording that just felt a bit off to me. I thought that I would read through some of the MEF material to broaden my QoS horizon and see what other terms are being used. At the very least I will have learned something new.
If we start with the basics, we have flows in our networks and these flows have different needs regarding delay, jitter and packet loss. I will write different terms and I will Continue reading
As I learned in my early days in electronics, every wire is an antenna. This means that a signal in any wire, given enough power, can be transmitted, and that same signal, in an adjacent wire, can be received (and potentially decoded) through electromagnetic induction (Rule 3 may apply). This is a major problem in the carrying of signals through a wire, a phenomenon known as cross talk. How do communications engineers overcome this? By observing that a signal carried along parallel wires at opposite polarities will cancel each other out electromagnetically. The figure below might help out, if you’re not familiar with this.
This canceling effect of two waveforms traveling a pair of wires 180deg out of phase is why the twisted is in twisted pair, and why it’s so crucial not to unbundle too much wire when punching down a jack or connector. The more untwisted the wire there is, the less effective the canceling effect is around the punch down, and the more likely you are to have near end or far end crosstalk.
If you consider one row of memory in a chip one wire, and a second, adjacent row of memory in the Continue reading
Network engineer Joel Spencer arrived at work one morning to complaints of intermittent disconnects between applications. Packet captures showed mysterious missing bytes in packets. Join us for this true tale of real-life troubleshooting that everyone can learn from.
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Like all other ipSpace.net webinars, the IPv6 Microsegmentation webinar starts with a brief description of the problem we’re trying to solve: the IPv6 first-hop security challenges.
For an overview of this problem, watch this free video from the IPv6 microsegmentation webinar, for more details, watch the IPv6 Security webinar.
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