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Wednesday, October 14, 2015

Cisco IOS OSPF Hidden Command: show ip ospf route

I saw this Cisco IOS hidden command show ip ospf route for OSPF in this post. I tried to create a running example for myself so I can learn more about this hidden command.

Monday, June 22, 2015

Checking system-wide uptime on several Cisco hardware platforms

We all know adding redundant supervisors/CPUs to any given system, we can increase the uptime for that system. With In-Service Software Upgrade (ISSU), Cisco hardware even allow us to upgrade the operating system software on-the-fly without stopping the whole system.

Flowers of Cassia fistula was blooming together in southern Taiwan starting from mid-May.
This photo was taken around this location in Baihe District of Tainan City, Taiwan.

An interesting question might be asked. Does Cisco hardware keep track of system uptime even upon supervisor/CPU failover events? And how to display the system uptime, in addition to individual supervisor/CPU uptime?

I spent some time and I summarize my findings in this post.

Sunday, April 12, 2015

Why should we turn off mobile phones when we travel in an airplane, Part 2

With discussion in previous post, we now know the mobile phone’s GSM TDMA signal pattern would generate buzzing sound on audio speakers. Now, how this is buzzing sound related to the safety of air planes?

After watching many videos of “Mayday, Air Crash Investigation” TV programs, I start to understand that today’s plane communications are still running analog technologies. Pilots would hear the buzzing sound generated by your mobile phone.

Fresh tomatos.
Photo taken in Hsinchu County, Taiwan.

Sunday, February 22, 2015

Video @Scale, "Introducing 6-pack, the First Open Hardware Modular Switch"

I really should have found and watched this video earlier!

This video is presented by Yuval Bachar, the same person posted this announcement on the Facebook Blog.

Here are some quick notes I took after watching this video.

Friday, February 20, 2015

Three configuration management features I like about Cisco IOS XR

I like more and more about Cisco IOS XR after I start to play with it. Here are three quick things I like about IOS XR.

Tomato farm and yellow tomato flowers.
Photo taken in 
Hsinchu County, Taiwan.

Friday, February 13, 2015

Some handy commands I use to save my time doing Cisco IOS XR labs

Remember: Default behaviors of Cisco IOS XR are there to secure your router even we forget to configure them. Never try to disable them on any production network!

For lab practice, however, security is not my concern at all. I list some of my handy configuration fragments to save me time when I do IOS XR labs. I hope they are also helpful to you!

Flower of strawberry.
Photo taken in Hsinchu County, Taiwan.

Two quick observations of Facebook’s announcement of “6-pack” open hardware modular switch

Facebook announced an introduction to its "6-pack" open hardware module switch 20 hours ago. Here are my two quick observations of "6-pack".

Thursday, January 29, 2015

Why should we turn off mobile phones when we travel in an airplane, Part 1

This video is funny. But some of the challenges from the passengers are quite true.

  • "90-Million -dollar aircraft can't ignore the signals from my 40-dollar iPod Shuffle?"
  • "Can I hold this plane hostage with my (Nintendo) 3DS?"
  • "How come the plane is not interfering with my phone?"
  • "Why don't other phones interfere my phone?"
  • "I just always leave my phone on and nothing happened?"

I think all the fears of "interferences to navigation" was because of some sound like this one.

Tuesday, January 27, 2015


Wavelength-division Multiplexing (WDM) is a technology we can put several laser light beams into the same optical fiber. The light beams are identified by their unique physical properties: wavelengths. Because of this, all such technologies are collectively called Wavelength-division Multiplexing.

By TotoBaggins on Wikipedia.

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