Ethernet Testing Parameters

Testing Ethernet Services

The Ethernet connections must be tested to ensure

that they are operating correctly and also they are

performing to the required levels.This is done by testing

 the bandwidth, the delay and the loss of frames in the

 connection. In Ethernet terms these are called

Throughput, Latency and Frame Loss.

Throughput

Data throughput is simply the maximum amount of data,

that can be transported from source to destination.

However the definition and measuring of throughput is

complicated by the need to define an acceptable level of

quality. For example, if 10% errored or lost frames were

deemed to be acceptable then the throughput would be

measured at 10% error rate. Here we have

generally accepted definition that throughput should be

measured with zero errors or lost frames.

In any given Ethernet system the absolute maximum

throughput will be equal to the data rate, e.g. 10 Mbit/s

100 Mbit/s or 1000 Mbit/s. In practice these figures

cannot be achieved because of the effect of frame size.

The smaller size frames have a lower effective

throughput than the larger sizes because of the addition

of the pre-amble and the interpacket gap bytes, which do

not count as data.

Latency

Latency is the total time taken for a frame to travel from

source to destination. This total time is the sum of both

the processing delays in the network elements and the

propagation delay along the transmission medium.

In order to measure latency a test frame containing a

time stamp is transmitted through the network. The time

stamp is then checked when the frame is received. In

order for this to happen the test frame needs to return to

the original test set by means of a loopback (round-trip

delay).

Frame Loss

Frame loss is simply the number of frames that were

transmitted successfully from the source but were never

received at the destination. It is usually referred to as

frame loss rate and is expressed as a percentage of the

total frames transmitted. For example if 1000 frames

were transmitted but only 900 were received the frame

loss rate would be: (1000 – 900) / 1000 x 100% = 10%

Frames can be lost, or dropped, for a number of reasons

including errors, over-subscription and excessive delay.

Errors - most layer 2 devices will drop a frame with an

incorrect FCS. This means that a single bit error in

transmission will result in the entire frame being

dropped. For this reason BER, the most fundamental

measure of a SONET/SDH service, has no meaning in

Ethernet since the ratio of good to errored bits cannot be

ascertained.

Oversubscription - the most common reason for frame

loss is oversubscription of the available bandwidth. For

example, if two 1000 Mbit/s Ethernet services are

mapped into a single 622 Mbit/s SONET/SDH pipe (a

common scenario) then the bandwidth limit is quickly

reached as the two gigabit Ethernet services are loaded.

When the limit is reached, frames may be dropped.

Excessive Delay - The nature of Ethernet networks

means that it is possible for frames to be delayed for

considerable periods of time. This is important when

testing as the tester is “waiting” for all of the transmitted

frames to be received and counted. At some point the

tester has to decide that a transmitted frame will not be

received and count the frame as lost. The most common

time period used to make this decision is the RFC

specification of two seconds. Thus any frame received

more then two seconds after it is transmitted would be

counted as lost.

Know-how for types of Viruses

Adware
Adware is software that presents banner ads or in pop-up windows through a bar that appears on a computer screen. Those advertising spots usually can't be removed and are consequently always visible. The connection data allow many conclusions on the usage behavior and are problematic in terms of data security.

Backdoors
A backdoor can gain access to a computer by going around the computer access security mechanisms.

A program that is being executed in the background generally enables the attacker almost unlimited rights. User's personal data can be spied with the backdoor's help, but are mainly used to install further computer viruses or worms on the relevant system.

Boot viruses
The boot or master boot sector of hard drives is mainly infected by boot sector viruses. They overwrite important information necessary for the system execution. One of the awkward consequences: the computer system cannot be loaded any more…

Bot-Net
A Bot-Net is collection of softwarre bots, which run autonomously. A Bot-Net can comprise a collection of cracked machines running programs (usually referred to as worms, Trojans) under a common command and control infrastructure. Boot-Nets server various purposes, including Denial-of-service attacks, etc., partly without the affected PC user's knowledge. The main potential of Bot-Nets is that the networks can achieve dimensions on thousands of computers and its bandwidth sum bursts most conventional Internet accesses.

Dialer
A dialer is a computer programm that establishes a connection to the Internet or to another computer network through the telephone line or the digital ISDN network. Fraudsters use dialers to charge users high rates when dialing up to the Internet without their knowledge.

EICAR test file
The EICAR test file is a test pattern that was developed at the European Institute for Computer Antivirus Research for the purpose to test the functions of anti-virus programs. It is a text file which is 68 characters long and its file extension is “.COM” all virus scanners should recognize as virus. 

Exploit
An exploit (security gap) is a computer program or script that takes advantage of a bug, glitch or vulnerability leading to privilege escalation or denial of service on a computer system. A form of an exploit for example are attacks from the Internet with the help of manipulated data packages. Programs can be infiltrated in order to obtain higher access.

Grayware
Grayware operates in a way similar to malware, but it is not spread to harm the users directly. It does not affect the system functionality as such. Mostly, information on the patterns of use is collected in order to either sell these data or to place advertisements systematically.

Hoaxes
The users have obtained virus alerts from the Internet for a few years and alerts against viruses in other networks that are supposed to spread via email. These alerts are spread per email with the request that they should be sent to the highest possible number of colleagues and to other users, in order to warn everyone against the "danger".

Honeypot
A honeypot is a service (program or server), which is installed in a network.

It has the function to monitor a network and to protocol attacks. This service is unknown to the legitime user - because of this reason he is never addressed. If an attacker examines a network for the weak points and uses the services which are offered by a Honeypot, it is protocolled and an alert sets off.

Keystroke logging
Keystroke logging is a diagnostic tool used in software development that captures the user's keystrokes. It can be useful to determine sources of error in computer systems and is sometimes used to measure employee productivity on certain clerical tasks. Like this, confidential and personal data, such as passwords or PINs, can be spied and sent to other computers via the Internet. 

Macro viruses
Macro viruses are small programs that are written in the macro language of an application (e.g. WordBasic under WinWord 6.0) and that can normally only spread within documents of this application. Because of this, they are also called document viruses. In order to be active, they need that the corresponding applications are activated and that one of the infected macros has been executed. Unlike "normal" viruses, macro viruses do consequently not attack executable files but they do attack the documents of the corresponding host-application.

Polymorph viruses
Polymorph viruses are the real masters of disguise. They change their own programming codes - and are therefore very hard to detect.

Program viruses
A computer virus is a program that is capable to attach itself to other programs after being executed and cause an infection. Viruses multiply themselves unlike logic bombs and Trojans. In contrast to a worm, a virus always requires a program as host, where the virus deposits his virulent code. The program execution of the host itself is not changed as a rule.

Script viruses and worms
Such viruses are extremely easy to program and they can spread - if the required technology is on hand - within a few hours via email round the globe.

Script viruses and worms use a script language such as Javascript, VBScript etc. to infiltrate in other new scripts or to spread by activation of operating system functions. This frequently happens via email or through the exchange of files (documents).

A worm is a program that multiplies itself but that does not infect the host. Worms can consequently not form part of other program sequences. Worms are often the only possibility to infiltrate any kind of damaging programs on systems with restrictive security measures.

Spyware
Spyware are so called spy programs that intercept or take partial control of a computer's operation without the user's informed consent. Spyware is designed to expolit infected computers for commerical gain. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements. AntiVir is able to detect this kind of software with the category "ADSPY" or "adware-spyware".

Trojan horses (short Trojans)
Trojans are pretty common nowadays. We are talking about programs that pretend to have a particular function, but that show their real image after execution and carry out a different function that, in most cases, is destructive. Trojan horses cannot multiply themselves, which differenciates them from viruses and worms. Most of them have an interesting name (SEX.EXE or STARTME.EXE) with the intention to induce the user to start the Trojan. Immediately after execution they become active and can, for example, format the hard drive. A dropper is a special form of Trojan that 'drops' viruses, i.e. embeds viruses on the computer system.

Zombie
A Zombie-PC is a computer that is infected with malware programs and that enables hackers to abuse computers via remote control for criminal purposes. The affected PC, for example, can start Denial-of-Service- (DoS) attacks at command or send spam and phishing emails.

Something about Gs in telecommunication world...

0G: phones, standing for the 1st generation of mobile phones, were satellite phones developed for boats mainly – but anyone could get one in one’s car in the beginning of the 90s for several thousand dollars. Networks such as Iridium, Global Star and Eutelsat were truly worldwide (although for physical reasons, think of a satellite as a fixed point above the equator, some Northern parts of Scandinavia aren’t reachable), and everybody thought at that time that satellite phones would become mainstream products as soon as devices got smaller and cheaper. This vision proved wrong when the GSM concretely came to life in 1990/1991 in Finland.

1G: Firstly, there were analog GSM systems, that existed for a few years. And then came the digital systems.

2G: the second generation of mobile telecommunications still is the most widespread technology in the world; you’ve basically all heard of the GSM norm (GSM stands for Groupe Spécial Mobile in French, renamed in Global System for Mobility). The GSM operates in the 850Mhz. and 1900Mhz. bands in the US, & 900Mhz. and 1.8Mhz. bands in the rest of the world (eg did you know Bluetooth stands in the 2.4Ghz. area, just like your…microwave!? But that’s another story, not related to this article) and delivers data at the slow rate of 9.6 Kbytes/sec.

2.5G: For that last reason (9.6 Kbytes/sec doesn’t allow you to browse the Net or up/download an image), telco operators came up with the GPRS (remember all the hype around the Wap) which could enable much faster communications (115Kbytes.sec). But the market decided it was still not enough compared to what they had at home.

2.75G: EDGE (I just called it 2.75G, 2.5′s not the official or unofficial number at all), which is a pretty recent standard, allows for downloading faster. Since mobile devices have become both a TV and a ‘walkman’ or music player, people needed to be able to watch streaming video and download mp3 files faster – that’s precisely what EDGE allows for and that’s for the good news. The bad news is that if EDGE rocks at downloading, it’s protocol is asymmetrical hence making EDGE suck at uploading ie broadcasting videos of yours for instance. Still an interesting achievement thanks to which data packets can effectively reach 180kbytes/sec. EDGE is now widely being used.

3G: also called UMTS (Universal Mobile Telecommunications Standard). Aimed at enabling long expected videoconferencing, although nobody seems to actually use it (do you know any?). Its other name is 3GSM, which says literally that UMTS is 3 times better than GSM. One issue though: depending on the deployment level of the area you are in and your device, your phone will (have to be) handle(d) from the GSM network to the UMTS network, and conversely – making billing more complex to understand for the consumers. One of the major positive points of UMTS is its global roaming capabilities (roaming is the process that allows you, at a cost, to borrow bandwidth from a telco provider that’s not yours; you usually use roaming when calling from abroad).

3.5G or 3G+: HSDPA is theoretically 6 times faster than UMTS (up to 3.6 Mbytes/sec)! Practically speaking, this would mean downloading an mp3 file would take about 30 secs instead of something like 2 minutes. Not bad, uh?

4G: still a research lab standard, at least to my knowledge, that should combine the best of cellphone network technologies with WiMax, wireless Internet, voice over IP and IPv6 (a post about the latter soon). Data rates are expected to reach 100 Mbytes/sec.

Difference between Symbian3 and Android2.2 Platforms for Mobile Phones

Symbian 3 vs Android 2.2 Gingerbread

Symbian 3 and Android 2.2 (Gingerbread) are operating systems for mobile phones and handheld devices. Symbian is an open source platform developed by Nokia and it is mainly used in Nokia phones while Android is also an open source platform developed by software giant Google. Different versions of both the operating systems have been released and Symbian 3 and Android 2.2 or Froyo are one of them.

Symbian 3

Symbian 3 is the latest version of the Symbian mobile platform. A number of developments have been made ranging from architectural renewal in networking and graphics to advancements in the usability of the operating system. The user interface has been made faster than the previous versions. Now, it is easy to connect to the web browser. The radio and gaming has been improved too on this version of Symbian OS. The whole operating system is said to be better, simpler and faster.

The ‘single tap’ method has been applied to the touch interface and the users do not need to tap to select and then tap again for action. It is easier to navigate the user interface. The process of connecting to internet is also easier in this version as the platform-wide behavior can be configured easily by using new global settings.

The hardware acceleration has been fully utilized by the new graphics architecture which also helps in delivering responsive as well as faster user interface. With this architecture, new transitions and effects can be added to the user interface. The data networking architecture has also been modified so that different network aware applications can be handled easily.

The Home screen has also been improved in this new version. Now multiple pages of widgets can be used on the home screen and users can easily navigate between them with a gesture. Multiple widgets’ instances are supported by the Home screen of Symbian 3 platform.

Android 2.2

Andoid 2.2 or Froyo is the next upgrade to Android 2.1 or Éclair. It is developed by Google. Several new features have been added to this version of Android mobile operating system.

A new tips widget has been added to the OS that helps users in configuring their home screens with widgets and shortcuts in an efficient manner. Dedicated shortcuts for Browser, App launcher and Phone have been provided on the Home screen and users can access them from any one of the five Home screens.

Alpha-numeric or numeric pin password protection to unlock the device has also been added to the OS. This greatly helps in improving the security. Remote wipe has also been added through which the device can be reset remotely by Exchange administrators.

Exchange account can be easily setup and synced with the help of Auto discovery. Auto-complete feature have been provided into the email application which searches the global address lists. The gallery has also been improved as users can easily peek into the pictures using the zoom gesture.

Difference between Symbian 3 and Android 2.2 • Symbian 3 OS has been developed by Nokia while Android 2.2. has been developed by Google. • Nokia N8 is the only phone that currently supports the Symbian 3 platform while Android 2.2 is available in most of today’s Smartphones. • There is less number of applications based on Symbian 3 OS as compared to Android. • The Symbian 3 OS supports three Home screens with six static slots on each screen whereas Android supports five Home screens with more dynamically fitting widgets. • Android 2.2 has built-in support for Flash 10.1 and Wifi hotspot but it does not supports different video formats except the Samsung Galaxy S Smartphone whereas Symbian 3 has Nokia N8 that supports wide variety of video formats.

Read more: http://www.differencebetween.com/difference-between-symbian-3-and-android-2-2-gingerbread/#ixzz1UZG81rsE