VoIP Technology

This is from Fierce VOIP
The foundation of VoIP networks and VoIP technology is a set of protocols called H.323. These protocols were established by the Telecommunications Sector of the International Telecommunication Union (ITU-T). H.323 specifies components, protocols, and procedures for real-time point-to-point and multipoint multimedia communication over packet-based networks. It also sets interoperability guidelines for communication between H.323-enabled networks and other conferencing standards.

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Defination of VOIP

From Vonage

Voice over Internet Protocol (VoIP) is a reliable technology for transmitting ordinary telephone calls over your internet connection using packet linked routes, also called IP Telephony . Internet Protocol involves the transmission of telephone calls over a data network like the Internet that can reach any telephone on the public-switched telephone network (PSTN).

From WIKIPEDIA

Voice over IP (also called VoIP, IP Telephony, and Internet telephony) is the routing of voice conversations over the Internet or any other IP network. The voice data flows over a general-purpose packet-switched network, instead of the traditional dedicated, circuit-switched voice transmission lines.

From Encarta Reference

Voice Over Internet Protocol (VOIP) is a method for making telephone calls over the Internet by sending voice data in separate packets, just as e-mail is sent. Each packet is assigned a code for its destination, and the packets are then reassembled in the correct order at the receiving end. Recent technological improvements have made VOIP almost as seamless and smooth as a regular telephone call.

Session variables problem

I met the session variables problem in IIS6.
I use global.asa as web application.
Same coding, it works under IIS5 of windows 2000 and IIS5.1 of windows xp, but it lost session variables under IIS6 of windows2003.
Sometimes I need to log in more than one time to get in the required page.
Tonight, I solve the problem.

Microsoft introduced several new features into Windows 2003/IIS6
webserver that affect how sessions and application pools are handled.
*Application Pools*
Most webhosting companies host multiple websites in the same application pool. When resources are maxed out for a application pool IIS 6 starts to recycle these sites causing application variables to be lost for those recycled sites.
If you are experiencing application/session loss symptoms then we would recommend asking your webhosting company to place you in your own application pool with all recycling options disabled and the recycle worker process set to recycle only once during the day at a set time.

I made a new applicaiton pool which is used by my application only.
So the problem disappeared.
Steps as below:
Step 1:
Add new application pool.
applicationpooladd

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AUTOSTITCH

This program is known from a Chinese Blog. Later I found the author is a PHD student of UBC, Matthew Brown.
AUTOSTITCH is the first fully automatic 2D image stitcher.
Sometime we call it a panorama program.

Capable of stitching full view panoramas without any user input whatsoever, AutoStitch is a breakthrough technology for panoramic photography, VR and visualisation applications.
AutoStitch is built using cutting edge research from the AI lab at UBC, but it’s incredibly simple to use! Just select a set of photos, and AutoStitch does the rest: digital photos in, panoramas out.

Following is a demo photo I took outside of my office tower yesterday.
panodemo

Made by 5 photos.
He is periodically updating the demo version of AutoStitch. Please download the latest version from this webpage.
It is free green program. Easy to use.
Thanks for Matthew Brown’s wisdom to develop this smart program.

In-Out Board

free_40_ssh_l

This is a web-based In-Out Board program.
It is totally free to download, use.
Pentacle (In Out Board) was started as an idea I had in the early part of 2003 when I was supposed to be running the intranet site design side of a local insurance brokerage company.
It was almost 2 months from the initial idea till the launch of Pentacle on the April 2003. During these 2 months much time was spent in researching, planning, designing, developing applications, and writing tutorials and articles.
After used internally about 2 years, I think about to share it with all other people need in/out board on their desktop .
Pentacle Free Limited Version was started, and is improvd time by time. I hope it is alway be on your desktop free of charge.
http://www.g2soft.net/

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Pagerank stop working

After I installed the new version Google Toolbar 3.0.123, abut 2 hours later, I found that Page Rank information are always unavailable. Even the site: www.google.com
In the begining I thought it happened because of the new version’s problem. I downgrade to Version 2.0. Still unavilable.
pr0

I checked the help of Google Toolbar. It said:

My PageRank button is always grayed out. Is it broken?
The PageRank button will appear grayed out on sites that are not currently included in the Google index. As a test, if you visit www.google.com, the PageRank bar should show a score of 10/10.
If it does not, it is most likely because the PageRank feature is incompatible with some aspect of your system. Often, users who work behind a firewall or proxy encounter this problem.
Unfortunately, we do not have a solution to pass along at this time. Our Toolbar engineering team is investigating this issue, and we hope to release an improved version of the PageRank feature in the future. In the meantime, we would recommend that you disable PageRank by performing the steps below:
1. Click on the “Options” button on your Toolbar.
2. Un-check the box next to “PageRank display.”
3. Click “OK.”

Today, I know that not me only. A lot of people are in same situation.
PRchecker reported that:
28 May, 2005 – Update: Google.com have stoped their pagerank service today, and

ALL the sites have ZERO rank now. We do not know if this is a temporary problem, but we hope it is, and we hope they will resolve this issue in several days, we’ll post an update when it is available.

In the Google Toolbar site, you can find no pagerank field in the toolbar image the provided.
This is the image from their site:
toolbarv3
I think pagerank will retire soon.

Wireless Network Concern

Now more and more network build by wireless equipments.
There are still something concern.
1) What is the range of wireless?
improve_02

Types of Wi-Fi Network
Protocol Maximum Speed Average Speed Wireless Range
802.11a 54Mbps 27Mbps 12m indoors, 30m line-of-sight outdoors
802.11b 11Mbps 4.5Mbps 30m indoors, 120m line-of-sight outdoors
802.11g 54Mbps 7Mbps (in compatibility mode), 16Mbps (with other 802.11g devices) 30m indoors, 120m line-of-sight outdoors

Standard construction walls can reduce the transmission distance by as much as 50%.

So, put the wireless router in the center of the house.

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