Optical Fiber Connectors

Optical fiber connectors are mechanical devices that are placed at the end of a fiber cable, allowing it to be connected to telecommunication equipment such as another cable, a receiver or a light source. They align the core of microscopic fibers together so light pulses can travel through them and allow communication. These devices make temporary links, which means they can be easily joined and detached.

Over the course of optical fiber technology development and improvement, several communication companies have created and introduced more than 100 connectors to the market, but just a few of them made it to the present days. And even fewer are considered the most used.

Optical Fiber Connectors Types

Optical fiber connectors Optical fiber connectors are used in premises installations, inside and outside plant applications, in CATV and telephony systems to join cables and equipment where a connect/disconnect capability is needed. Connectors are considered the weakest link in a fiber optic system, because they mark a spot in which signal power can be lost. So for optical fiber systems to have an outstanding performance, well designed connectors, good terminations and an installer with skills are needed.

There are several types of optical fiber connectors and they are all integrated by three main mechanisms:

The ferrule: This is the most important component of fiber optic connectors because it holds, protects and aligns the glass fiber. Ferrules are usually made of ceramic, high-quality plastic or metal. Of all those materials, zirconia ferrules are the ones that offer the highest performance and durability after several mating cycles.

Coupling mechanism: It keeps the connector in place when it is joined to another device. It could be push-pull or bayonet style.

Connector body: Is the structure that holds the ferrule, the coupling mechanism and the boot. It is made of plastic or metal.




Connectors’ end-face

The connectors’ end-face determines what the return loss, also known as back reflection, of a fiber optic cable will be. Return loss is the loss of power that happens when light returns from the fiber to the light source device due to discontinuities or airs gaps caused in the ferrule’s end-face. It is measured in decibels.

Ferrules are polished in different ways, which classifies connectors as:

- PC (Physical Contact): PC connectors are polished with a slight curvature, which reduces the air gaps between fibers. These connectors’ back reflection is between 30dB and 40dB.

- UPC (Ultra Physical Contact): UPC connectors also have a convex end-face, but have a finer surface finish. Their return loss goes from -40dB from -55dB, which makes them reliable for transmitting TV and data signals.

- APC (Angled Physical Contact): APC connectors have an 8° angle cut in their ferrules, which makes connections between optical fibers even tighter. Industry standards indicate that APC connectors back reflection is -60dB.

Source : http://www.networking-forum.com/viewtopic.php?f=24&t=48286

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Big Brother and Ndisuio.sys A new Internet phenomenon?

Ndisuio.sys, a very mysterious system file is present in Windows XP and is a driver for wireless things such as wi-fi and bluetooth. However, there have been many issues with this file downloading immense amounts of data and perhaps causing activity that is "big brother"ish.

The fact that hardly any information on this file downloading data is available by Microsoft makes things quite suspicious about it. It has even been noted that it looked as if it was transferring data to major companies like Comcast, Road Runner, Time Warner, BTC and Verizon.

The good news is, it turns out this file duplicates data that is sent/received, so wherever you go, it will also transfer the data to that file but it does not leave the computer/network so it's not spyware. So it's not as much of a big brother situation then it looks like. It simply performs internal communication tasks and stands for NDIS user I/O, hence, NDISUIO. NDISUIO is also used as a driver by many developers as it makes certain wireless network tasks easier such as implementing it for 802.11x connections. Some firewalls also use it as it can get the data in order to filter it.

But duplicating this data can hog resources for no reason, so disabling it is the best thing to do. The data rate of this file's received data is huge, so that indicates that the data transfer is not over the Internet, but locally. So it's just a duplicate of network activity but because it's local everything transfers faster but uses more resources then casual internet usage as there's more data involved at a given time span of 1 second, for example.

To disable this file, go to the control panel, administration tools, services, Wireless Zero Configuration, double click and disable it. This file is probably required to run if you use any linksys wireless devices. read more...

BandWidth Explained

This is well written explanation about bandwidth, very useful info.

BandWidth Explained

Most hosting companies offer a variety of bandwidth options in their plans. So exactly what is bandwidth as it relates to web hosting? Put simply, bandwidth is the amount of traffic that is allowed to occur between your web site and the rest of the internet. The amount of bandwidth a hosting company can provide is determined by their network connections, both internal to their data center and external to the public internet.


Network Connectivity

The internet, in the most simplest of terms, is a group of millions of computers connected by networks. These connections within the internet can be large or small depending upon the cabling and equipment that is used at a particular internet location. It is the size of each network connection that determines how much bandwidth is available. For example, if you use a DSL connection to connect to the internet, you have 1.54 Mega bits (Mb) of bandwidth. Bandwidth therefore is measured in bits (a single 0 or 1). Bits are grouped in bytes which form words, text, and other information that is transferred between your computer and the internet.

If you have a DSL connection to the internet, you have dedicated bandwidth between your computer and your internet provider. But your internet provider may have thousands of DSL connections to their location. All of these connection aggregate at your internet provider who then has their own dedicated connection to the internet (or multiple connections) which is much larger than your single connection. They must have enough bandwidth to serve your computing needs as well as all of their other customers. So while you have a 1.54Mb connection to your internet provider, your internet provider may have a 255Mb connection to the internet so it can accommodate your needs and up to 166 other users (255/1.54).

Traffic

A very simple analogy to use to understand bandwidth and traffic is to think of highways and cars. Bandwidth is the number of lanes on the highway and traffic is the number of cars on the highway. If you are the only car on a highway, you can travel very quickly. If you are stuck in the middle of rush hour, you may travel very slowly since all of the lanes are being used up.

Traffic is simply the number of bits that are transferred on network connections. It is easiest to understand traffic using examples. One Gigabyte is 2 to the 30th power (1,073,741,824) bytes. One gigabyte is equal to 1,024 megabytes. To put this in perspective, it takes one byte to store one character. Imagine 100 file cabinets in a building, each of these cabinets holds 1000 folders. Each folder has 100 papers. Each paper contains 100 characters - A GB is all the characters in the building. An MP3 song is about 4MB, the same song in wav format is about 40MB, a full length movie can be 800MB to 1000MB (1000MB = 1GB).

If you were to transfer this MP3 song from a web site to your computer, you would create 4MB of traffic between the web site you are downloading from and your computer. Depending upon the network connection between the web site and the internet, the transfer may occur very quickly, or it could take time if other people are also downloading files at the same time. If, for example, the web site you download from has a 10MB connection to the internet, and you are the only person accessing that web site to download your MP3, your 4MB file will be the only traffic on that web site. However, if three people are all downloading that same MP at the same time, 12MB (3 x 4MB) of traffic has been created. Because in this example, the host only has 10MB of bandwidth, someone will have to wait. The network equipment at the hosting company will cycle through each person downloading the file and transfer a small portion at a time so each person's file transfer can take place, but the transfer for everyone downloading the file will be slower. If 100 people all came to the site and downloaded the MP3 at the same time, the transfers would be extremely slow. If the host wanted to decrease the time it took to download files simultaneously, it could increase the bandwidth of their internet connection (at a cost due to upgrading equipment).

Hosting Bandwidth

In the example above, we discussed traffic in terms of downloading an MP3 file. However, each time you visit a web site, you are creating traffic, because in order to view that web page on your computer, the web page is first downloaded to your computer (between the web site and you) which is then displayed using your browser software (Internet Explorer, Netscape, etc.) . The page itself is simply a file that creates traffic just like the MP3 file in the example above (however, a web page is usually much smaller than a music file).

A web page may be very small or large depending upon the amount of text and the number and quality of images integrated within the web page. For example, the home page for CNN.com is about 200KB (200 Kilobytes = 200,000 bytes = 1,600,000 bits). This is typically large for a web page. In comparison, Yahoo's home page is about 70KB.

How Much Bandwidth Is Enough?

It depends (don't you hate that answer). But in truth, it does. Since bandwidth is a significant determinant of hosting plan prices, you should take time to determine just how much is right for you. Almost all hosting plans have bandwidth requirements measured in months, so you need to estimate the amount of bandwidth that will be required by your site on a monthly basis

If you do not intend to provide file download capability from your site, the formula for calculating bandwidth is fairly straightforward:

Average Daily Visitors x Average Page Views x Average Page Size x 31 x Fudge Factor

If you intend to allow people to download files from your site, your bandwidth calculation should be:

[(Average Daily Visitors x Average Page Views x Average Page Size) +
(Average Daily File Downloads x Average File Size)] x 31 x Fudge Factor

Let us examine each item in the formula:

Average Daily Visitors - The number of people you expect to visit your site, on average, each day. Depending upon how you market your site, this number could be from 1 to 1,000,000.

Average Page Views - On average, the number of web pages you expect a person to view. If you have 50 web pages in your web site, an average person may only view 5 of those pages each time they visit.

Average Page Size - The average size of your web pages, in Kilobytes (KB). If you have already designed your site, you can calculate this directly.

Average Daily File Downloads - The number of downloads you expect to occur on your site. This is a function of the numbers of visitors and how many times a visitor downloads a file, on average, each day.

Average File Size - Average file size of files that are downloadable from your site. Similar to your web pages, if you already know which files can be downloaded, you can calculate this directly.

Fudge Factor - A number greater than 1. Using 1.5 would be safe, which assumes that your estimate is off by 50%. However, if you were very unsure, you could use 2 or 3 to ensure that your bandwidth requirements are more than met.

Usually, hosting plans offer bandwidth in terms of Gigabytes (GB) per month. This is why our formula takes daily averages and multiplies them by 31.

Summary

Most personal or small business sites will not need more than 1GB of bandwidth per month. If you have a web site that is composed of static web pages and you expect little traffic to your site on a daily basis, go with a low bandwidth plan. If you go over the amount of bandwidth allocated in your plan, your hosting company could charge you over usage fees, so if you think the traffic to your site will be significant, you may want to go through the calculations above to estimate the amount of bandwidth required in a hosting plan. read more...

Cant See Secure Sites

Fix the problem with seeing them secrue sites (banks or online stores) i found this very usefull to me at my work (isp backbone support lol, at the time i was regular support )

Any way... what u need to do is make a new notepad file and write in it the followng DLL's.. just copy-paste these

regsvr32 SOFTPUB.DLL
regsvr32 WINTRUST.DLL
regsvr32 INITPKI.DLL
regsvr32 dssenh.dll
regsvr32 Rsaenh.dll
regsvr32 gpkcsp.dll
regsvr32 sccbase.dll
regsvr32 slbcsp.dll
regsvr32 Cryptdlg.dll

and save it as > all file types, and make it something like securefix.bat.
then just run the file and ur problem shuld be gone. read more...

Block Websties Without Software

How To Block Websties Without Software, block websites

Steps:

1] Browse C:\WINDOWS\system32\drivers\etc
2] Find the file named "HOSTS"
3] Open it in notepad
4] Under "127.0.0.1 localhost" Add 127.0.0.2 www.sitenameyouwantblocked.com , and that site will no longer be accessable.
5] Done!

-So-

127.0.0.1 localhost
127.0.0.2 www.blockedsite.com

-->www.blockedsite.com is now unaccessable<-- 127.0.0.3="" 127.0.0.4="" 127.0.0.5="" add="" addy="" after="" and="" before.="" etc="" every="" for="" ie:="" in="" internal="" ip="" just="" last="" like="" number="" site="" span="" that="" the="" then="" to="" want="" www.blablabla.com="" you=""> read more...

Network Layers

If you really want to understand Linux network configuration, you must be able to distinguish each layer in the network. Here are the layers in the Internet, from the top level to the bottom level:

• Application Layer Contains the "language" that applications and servers use to communicate; usually a protocol of some sort. Common application layer protocols include Hypertext Transfer Protocol (HTTP, used for the World Wide Web), Secure Shell (SSH), and the File Transfer Protocol (FTP).

• Transport Layer Defines the data transmission characteristics of the application layer. This is host-specific information, and it includes data-integrity checking, source and destination ports, and specifications for breaking application data into packets. TCP (Transmission Control Protocol) is the most common transport layer protocol.

• Internet Layer Defines how to move packets from the source host to the destination host. The particular packet-transit rule set for the Internet is known as IP (Internet Protocol). This is sometimes called the network layer.

• Host-to-Network Layer Defines how to send packets from the Internet layer across the physical medium, such as Ethernet or a modem. This is sometimes called the physical layer.

This may sound overly complicated, but it's important that you understand it, because your data must travel through these layers twice before it reaches its destination. Your bytes leave the application layer on the source host, then go down to the physical medium, across the medium, and then up again to the application layer on the destination host.

Unfortunately, the layers sometimes bleed in strange ways, and terms like TCP/IP reflect the integration. The distinction is only getting more vague — in particular, devices that once only dealt with the Internet layer now sometimes look at the transport layer data to determine where to send data.

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How To: Change Your Ip In Less Then 1 Minute

let's do it:
1. Click on "Start" in the bottom left hand corner of screen
2. Click on "Run"
3. Type in "command" and hit ok

You should now be at an MSDOS prompt screen.
4. Type "ipconfig /release" just like that, and hit "enter"
5. Type "exit" and leave the prompt
6. Right-click on "Network Places" or "My Network Places" on your desktop.
7. Click on "properties"

You should now be on a screen with something titled "Local Area Connection", or something close to that, and, if you have a network hooked up, all of your other networks.

8. Right click on "Local Area Connection" and click "properties"
9. Double-click on the "Internet Protocol (TCP/IP)" from the list under the "General" tab
10. Click on "Use the following IP address" under the "General" tab
11. Create an IP address (It doesn't matter what it is. I just type 1 and 2 until i fill the area up).
12. Press "Tab" and it should automatically fill in the "Subnet Mask" section with default numbers.
13. Hit the "Ok" button here
14. Hit the "Ok" button again

You should now be back to the "Local Area Connection" screen.

15. Right-click back on "Local Area Connection" and go to properties again.
16. Go back to the "TCP/IP" settings
17. This time, select "Obtain an IP address automatically"
tongue.gif 18. Hit "Ok"
19. Hit "Ok" again
20. You now have a new IP address

With a little practice, you can easily get this process down to 15 seconds.

P.S:
This only changes your dynamic IP address, not your ISP/IP address. If you plan on hacking a website with this trick be extremely careful, because if they try a little, they can trace it back. read more...

Common FTP Error Codes

#Description

110 Restart marker reply. In this case, the text is exact and not left to the particular implementation; it must read: MARK yyyy = mmmm where yyyy is User-process data stream marker, and mmmm server's equivalent marker (note the spaces between markers and "=").
120 Service ready in nnn minutes.
125 Data connection already open; transfer starting.
150 File status okay; about to open data connection.
200 Command okay.
202 Command not implemented, superfluous at this site.
211 System status, or system help reply.
212 Directory status.
213 File status.
214 Help message.On how to use the server or the meaning of a particular non-standard command. This reply is useful only to the human user.
215 NAME system type. Where NAME is an official system name from the list in the Assigned Numbers document.
220 Service ready for new user.
221 Service closing control connection.
225 Data connection open; no transfer in progress.
226 Closing data connection. Requested file action successful (for example, file transfer or file abort).
227 Entering Passive Mode (h1,h2,h3,h4,p1,p2).
230 User logged in, proceed. Logged out if appropriate.
250 Requested file action okay, completed.
257 "PATHNAME" created.
331 User name okay, need password.
332 Need account for login.
350 Requested file action pending further information
421 Service not available, closing control connection.This may be a reply to any command if the service knows it must shut down.
425 Can't open data connection.
426 Connection closed; transfer aborted.
450 Requested file action not taken.
451 Requested action aborted. Local error in processing.
452 Requested action not taken. Insufficient storage space in system.File unavailable (e.g., file busy).
500 Syntax error, command unrecognized. This may include errors such as command line too long.
501 Syntax error in parameters or arguments.
502 Command not implemented.
503 Bad sequence of commands.
504 Command not implemented for that parameter.
530 Not logged in.
532 Need account for storing files.
550 Requested action not taken. File unavailable (e.g., file not found, no access).
551 Requested action aborted. Page type unknown.
552 Requested file action aborted. Exceeded storage allocation (for current directory or dataset).
553 Requested action not taken. File name not allowed. read more...