Custom Systems
Chicago Microsystems, Inc. is a OEM hardware builder manufacturing custom desktop and server solutions. We utilize the highest quality components from major vendors such as ASUS, Intel, Kingston and Western Digital. Being a full service system integrator that implements and supports our systems, we have the expertise in designing a system that will best meet your needs.
Industry surveys suggest that customers are happier with custom solutions from whitebox vendors compared to tier one vendors (such as HP or Dell). Click here to learn more about the benefits of acquiring a custom system from CMI.
Monday, August 3, 2009
Sunday, July 19, 2009
Terminology
Terminology
The term network TAP is analogous to phone tap or vampire tap. Some vendors have phrases for which TAP is an acronym; however, those are most likely bacronyms.
The monitored traffic is sometimes referred to as the pass-through traffic, while the ports that are used for monitoring are the monitor ports. There is also an aggregation port where in the Full Duplex World the "A" traffic is Aggregated with the "B" traffic resulting in one stream of data /packets for monitoring the Full Duplex communication. The packets must be aligned into a single stream using a time of arrival algorithm.
Vendors will tend to use terms in their marketing such as breakout, passive, aggregating, regeneration, inline power, and others. Common meanings will be discussed later. Unfortunately, vendors do not use such terms consistently. Before buying any products, be sure to understand the available features, and check with vendors or read the product literature closely to figure out how marketing terms correspond to reality. All of the "Vendor Terms" are common within the industry and have real definitions and are valuable points of consideration when buying a TAP device.
New Filterable TAP Technology
A new type of TAP, or network access point, is now available. This new type of TAP is called a "filterable" TAP. It is especially valuable in the 10 Gigabit environment because 10-Gigabit test equipment is very expensive. Some TAPs, like those from several vendors, offer the ability to utilize less expensive and more widely available 1-Gigabit monitoring and analysis tools with these 10 Gigabit networks. When used in this fashion, some form of load-balancing or port-bonding is recommended to avoid packet loss to the monitoring tools.
A filterable TAP, that provides advanced filtering, can selectively pass data, based on application, VLAN ID, or other parameters, to the 1-Gigabit port for deep analysis and monitoring, including IDS requirements.
Filtered access is also the best way to focus on business-critical traffic, or other specific areas of your network. At higher speeds, network traffic analysis cannot be performed using the older "capture and decode everything" philosophy. In this type of environment, focused access is the best way to enable traffic analysis, and often is the only way.
Any filterable TAP you consider must have a simple user interface for easy setup and management. Furthermore, it must be able to collect the Layer 1 and Layer 2 data, while still allowing for auto saving, and easy access to data by graphing programs. Such a TAP can be part of a strategy to monitor for essential metrics, such as frame errors and corrupted frames in IPv6.
The term network TAP is analogous to phone tap or vampire tap. Some vendors have phrases for which TAP is an acronym; however, those are most likely bacronyms.
The monitored traffic is sometimes referred to as the pass-through traffic, while the ports that are used for monitoring are the monitor ports. There is also an aggregation port where in the Full Duplex World the "A" traffic is Aggregated with the "B" traffic resulting in one stream of data /packets for monitoring the Full Duplex communication. The packets must be aligned into a single stream using a time of arrival algorithm.
Vendors will tend to use terms in their marketing such as breakout, passive, aggregating, regeneration, inline power, and others. Common meanings will be discussed later. Unfortunately, vendors do not use such terms consistently. Before buying any products, be sure to understand the available features, and check with vendors or read the product literature closely to figure out how marketing terms correspond to reality. All of the "Vendor Terms" are common within the industry and have real definitions and are valuable points of consideration when buying a TAP device.
New Filterable TAP Technology
A new type of TAP, or network access point, is now available. This new type of TAP is called a "filterable" TAP. It is especially valuable in the 10 Gigabit environment because 10-Gigabit test equipment is very expensive. Some TAPs, like those from several vendors, offer the ability to utilize less expensive and more widely available 1-Gigabit monitoring and analysis tools with these 10 Gigabit networks. When used in this fashion, some form of load-balancing or port-bonding is recommended to avoid packet loss to the monitoring tools.
A filterable TAP, that provides advanced filtering, can selectively pass data, based on application, VLAN ID, or other parameters, to the 1-Gigabit port for deep analysis and monitoring, including IDS requirements.
Filtered access is also the best way to focus on business-critical traffic, or other specific areas of your network. At higher speeds, network traffic analysis cannot be performed using the older "capture and decode everything" philosophy. In this type of environment, focused access is the best way to enable traffic analysis, and often is the only way.
Any filterable TAP you consider must have a simple user interface for easy setup and management. Furthermore, it must be able to collect the Layer 1 and Layer 2 data, while still allowing for auto saving, and easy access to data by graphing programs. Such a TAP can be part of a strategy to monitor for essential metrics, such as frame errors and corrupted frames in IPv6.
Advantages and features
Advantages and features
Older network technologies tended to be shared. Connecting a monitoring device to a shared network segment (i.e., piece of a network) was very easy -- just connect the monitoring device as you would any other host, and enable promiscuous mode. Modern network technologies tend to be switched, meaning that devices are connected using point-to-point links. If a monitoring device is connected to such a network, it will only see its own traffic. The network TAP allows the monitoring device to view the contents of a point-to-point link.
Modern network technologies are often full-duplex, meaning that data can travel in both directions at the same time. If a network link allows 100 Mbit/s of data to flow in each direction at the same time, this means that the network really allows 200 Mbit/s of aggregate throughput. This can present a problem for monitoring technologies if they have only one monitor port. Therefore, network TAPs for full-duplex technologies usually have two monitor ports, one for each half of the connection. The listener must use channel bonding or link aggregation to merge the two connections into one aggregate interface to see both halves of the traffic. Other monitoring technologies do not deal well with the full-duplex problem.
Once a network TAP is in place, the network can be monitored without interfering with the network itself. Other network monitoring solutions require in-band changes to network devices, which means that monitoring can impact the devices being monitored.
Once a TAP is in place, a monitoring device can be connected to it as-needed without impacting the monitored network.
Some TAPs have multiple output ports, or multiple pairs of output ports for full-duplex, to allow more than one device to monitor the network at the TAP point. These are often called regeneration TAPs.
A passive fiber optic tap.Some TAPs, particularly fiber TAPs, can use no power and no electronics at all for the pass-through and monitor portion of the network traffic. This means that the TAP should never suffer any kind of electronics failure or power failure that results in a loss of network connectivity. One way this can work, for fiber-based network technologies, is that the TAP divides the incoming light using a simple physical apparatus into two outputs, one for the pass-through, one for the monitor. This can be called a passive TAP. Other TAPs use no power or electronics for the pass-through, but do use power and electronics for the monitor port. These can also be referred to as passive.
Some TAPs operate at the physical layer of the OSI model rather than the data link layer. For example, they work with multi-mode fiber rather than 1000BASE-SX. This means that they can work with most data link network technologies that use that physical media, such as ATM and some forms of Ethernet. Network TAPs that act as simple optical splitters, sometimes called passive TAPs (although that term is not used consistently) can have this property.
Some network TAPs offer both duplication of network traffic for monitoring devices and SNMP services. Most major network TAP manufacturers offer TAPs with remote management through Telnet, HTTP, or SNMP interfaces. Such network TAP hybrids can be helpful to network managers who wish to view baseline performance statistics without diverting existing tools. Alternately, SNMP alarms generated by managed TAPs can alert network managers to link conditions that merit examination by analyzers to intrusion detection systems.
Some TAPs get some of their power (i.e., for the pass-through) or all of their power (i.e., for both pass-through and monitor) from the network itself. These can be referred to as having inline power.
Some TAPs can also reproduce low-level network errors, such as short frames, bad CRC or corrupted data.
Older network technologies tended to be shared. Connecting a monitoring device to a shared network segment (i.e., piece of a network) was very easy -- just connect the monitoring device as you would any other host, and enable promiscuous mode. Modern network technologies tend to be switched, meaning that devices are connected using point-to-point links. If a monitoring device is connected to such a network, it will only see its own traffic. The network TAP allows the monitoring device to view the contents of a point-to-point link.
Modern network technologies are often full-duplex, meaning that data can travel in both directions at the same time. If a network link allows 100 Mbit/s of data to flow in each direction at the same time, this means that the network really allows 200 Mbit/s of aggregate throughput. This can present a problem for monitoring technologies if they have only one monitor port. Therefore, network TAPs for full-duplex technologies usually have two monitor ports, one for each half of the connection. The listener must use channel bonding or link aggregation to merge the two connections into one aggregate interface to see both halves of the traffic. Other monitoring technologies do not deal well with the full-duplex problem.
Once a network TAP is in place, the network can be monitored without interfering with the network itself. Other network monitoring solutions require in-band changes to network devices, which means that monitoring can impact the devices being monitored.
Once a TAP is in place, a monitoring device can be connected to it as-needed without impacting the monitored network.
Some TAPs have multiple output ports, or multiple pairs of output ports for full-duplex, to allow more than one device to monitor the network at the TAP point. These are often called regeneration TAPs.
A passive fiber optic tap.Some TAPs, particularly fiber TAPs, can use no power and no electronics at all for the pass-through and monitor portion of the network traffic. This means that the TAP should never suffer any kind of electronics failure or power failure that results in a loss of network connectivity. One way this can work, for fiber-based network technologies, is that the TAP divides the incoming light using a simple physical apparatus into two outputs, one for the pass-through, one for the monitor. This can be called a passive TAP. Other TAPs use no power or electronics for the pass-through, but do use power and electronics for the monitor port. These can also be referred to as passive.
Some TAPs operate at the physical layer of the OSI model rather than the data link layer. For example, they work with multi-mode fiber rather than 1000BASE-SX. This means that they can work with most data link network technologies that use that physical media, such as ATM and some forms of Ethernet. Network TAPs that act as simple optical splitters, sometimes called passive TAPs (although that term is not used consistently) can have this property.
Some network TAPs offer both duplication of network traffic for monitoring devices and SNMP services. Most major network TAP manufacturers offer TAPs with remote management through Telnet, HTTP, or SNMP interfaces. Such network TAP hybrids can be helpful to network managers who wish to view baseline performance statistics without diverting existing tools. Alternately, SNMP alarms generated by managed TAPs can alert network managers to link conditions that merit examination by analyzers to intrusion detection systems.
Some TAPs get some of their power (i.e., for the pass-through) or all of their power (i.e., for both pass-through and monitor) from the network itself. These can be referred to as having inline power.
Some TAPs can also reproduce low-level network errors, such as short frames, bad CRC or corrupted data.
Disadvantages and problems
Disadvantages and problems
Network TAPs require additional hardware, so are not as cheap as technologies that leverage capabilities that are built-in to the network. They are easier to manage and normally provide more data than some network devices though.
Network TAPs can require channel bonding on monitoring devices to get around the problem with full-duplex discussed above. Vendors usually refer to this as aggregation as well.
Putting a network TAP into place can disrupt the network being monitored for a short time. It's better than taking a network down multiple times to deploy a monitoring tool though. Establishing good guidelines for placement of network taps is recommended procedure.
Monitoring large networks using network Taps can require a lot of monitoring devices. Some argue that other technologies scale better.[citation needed] SPAN ports are presumed free, but require more configuration than TAPs.
Even fully passive network TAPs introduce new points of failure into the network. There are several ways that taps can cause problems and this should be considered when creating a tap architecture. Consider non-powered taps for optical-only environments. This allows you to modify the intelligent aggregation taps that may be in use and avoids any complications when upgrading from 100 Megabit to Gigabit to 10 Gigabit. Redundant power supplies are highly recommended.
Network TAPs require additional hardware, so are not as cheap as technologies that leverage capabilities that are built-in to the network. They are easier to manage and normally provide more data than some network devices though.
Network TAPs can require channel bonding on monitoring devices to get around the problem with full-duplex discussed above. Vendors usually refer to this as aggregation as well.
Putting a network TAP into place can disrupt the network being monitored for a short time. It's better than taking a network down multiple times to deploy a monitoring tool though. Establishing good guidelines for placement of network taps is recommended procedure.
Monitoring large networks using network Taps can require a lot of monitoring devices. Some argue that other technologies scale better.[citation needed] SPAN ports are presumed free, but require more configuration than TAPs.
Even fully passive network TAPs introduce new points of failure into the network. There are several ways that taps can cause problems and this should be considered when creating a tap architecture. Consider non-powered taps for optical-only environments. This allows you to modify the intelligent aggregation taps that may be in use and avoids any complications when upgrading from 100 Megabit to Gigabit to 10 Gigabit. Redundant power supplies are highly recommended.
Comparison to other monitoring technologies
Comparison to other monitoring technologies
Various monitoring approaches can be used, depending on the network technology and the monitoring objective:
The simplest type of monitoring is logging in to an interesting device and running programs or commands that show performance statistics and other data. This is the cheapest way to monitor a network, and is highly appropriate for small networks. However, it does not scale well to large networks. It can also impact the network being monitored; see observer effect.
Another way to monitor devices is to use a remote management protocol such as SNMP to ask devices about their performance. This scales well, but is not necessarily appropriate for all types of monitoring. The inherent problems with SNMP are the polling effect. Many vendors have alleviated this by using intelligent polling schedulers, but this may still affect the performance of the device being monitored. It also opens up a host of potential security problems.
Network intrusion detection systems require a lot of host resources, so it is desirable to run such software on centralized monitoring systems rather than on individual hosts. Also, politically, sometimes one group runs the network and another group runs the computers, so the group that runs the network wants to have monitoring capabilities independent of the group that runs the computers.
Another method to monitor networks is by enable promiscuous mode on the monitoring host, and connecting it to a shared segment. This works well with older LAN technologies such as 10BASE-T Ethernet networks and FDDI networks. On such networks, any host can automatically see what all other hosts were doing by enabling promiscuous mode. However, modern switched network technologies such as those used on modern Ethernets provide, in effect, point-to-point links between pairs of devices, so it is hard for other devices to see traffic.
Another method to monitor networks is to use port mirroring (called "SPAN", for Switched Port Analyzer, by Cisco, and given other names by some other vendors) on routers and switches. This is a low-cost alternative to network TAPs, and solves many of the same problems. However, not all routers and switches support port mirroring and, on those that do, using port mirroring can affect the performance of the router or switch. These technologies may also be subject to the problem with full-duplex described elsewhere in this article, and there are often limits for the router or switch on how many pass-through sessions can be monitored, or how many monitor ports (generally two) can monitor a given session.
Various monitoring approaches can be used, depending on the network technology and the monitoring objective:
The simplest type of monitoring is logging in to an interesting device and running programs or commands that show performance statistics and other data. This is the cheapest way to monitor a network, and is highly appropriate for small networks. However, it does not scale well to large networks. It can also impact the network being monitored; see observer effect.
Another way to monitor devices is to use a remote management protocol such as SNMP to ask devices about their performance. This scales well, but is not necessarily appropriate for all types of monitoring. The inherent problems with SNMP are the polling effect. Many vendors have alleviated this by using intelligent polling schedulers, but this may still affect the performance of the device being monitored. It also opens up a host of potential security problems.
Network intrusion detection systems require a lot of host resources, so it is desirable to run such software on centralized monitoring systems rather than on individual hosts. Also, politically, sometimes one group runs the network and another group runs the computers, so the group that runs the network wants to have monitoring capabilities independent of the group that runs the computers.
Another method to monitor networks is by enable promiscuous mode on the monitoring host, and connecting it to a shared segment. This works well with older LAN technologies such as 10BASE-T Ethernet networks and FDDI networks. On such networks, any host can automatically see what all other hosts were doing by enabling promiscuous mode. However, modern switched network technologies such as those used on modern Ethernets provide, in effect, point-to-point links between pairs of devices, so it is hard for other devices to see traffic.
Another method to monitor networks is to use port mirroring (called "SPAN", for Switched Port Analyzer, by Cisco, and given other names by some other vendors) on routers and switches. This is a low-cost alternative to network TAPs, and solves many of the same problems. However, not all routers and switches support port mirroring and, on those that do, using port mirroring can affect the performance of the router or switch. These technologies may also be subject to the problem with full-duplex described elsewhere in this article, and there are often limits for the router or switch on how many pass-through sessions can be monitored, or how many monitor ports (generally two) can monitor a given session.
Application-oriented networking
Application-oriented networking
Application-oriented networking (AON) involves network devices designed to aid in computer
to-computer application integration.
Application-oriented networking was popularized by Cisco Systems in response to increasing use of XML messaging (combined with related standards such as XSLT, XPath and XQuery) to link miscellaneous applications, data sources and other computing assets.
Many of the operations required to mediate between applications, or to monitor their transactions, can be built into network devices that are optimized for the purpose.
The rules and policies for performing these operations, also expressed in XML, are specified separately and downloaded as required. Cisco has adopted the AON acronym as the name of a family of products that function in this way.
Application-oriented networking (AON) involves network devices designed to aid in computer
to-computer application integration.
Application-oriented networking was popularized by Cisco Systems in response to increasing use of XML messaging (combined with related standards such as XSLT, XPath and XQuery) to link miscellaneous applications, data sources and other computing assets.
Many of the operations required to mediate between applications, or to monitor their transactions, can be built into network devices that are optimized for the purpose.
The rules and policies for performing these operations, also expressed in XML, are specified separately and downloaded as required. Cisco has adopted the AON acronym as the name of a family of products that function in this way.
Tuesday, July 14, 2009
Networking Tips
Tips :
Computer networks are used to share the data and resources and for the communications. To get the optimized performance, data protection, maintenance, improved reliability and the security, every system administrator and network administrator should know the basic maintenance, troubleshooting and security techniques. Downtime is very dangerous for the critical network business applications and servers. In this article, you will learn some of the best networking tips and by using them you can get the optimized performance from your network.
Security :
A compute network is susceptible to the internet and external security related threats, which includes viruses, spyware, adware, Trojan horses, rootkits, web worms, intruders and hackers. To keep your network secure
Firewall :
Install and configure a software/hardware firewall on your gateway and all other computers in your network. Firewall is used monitor the inbound and outbound traffic and block the unauthorized access and hackers’ attacks.
Antivirus: Install antivirus software such as Norton Antivirus, Trend Micro Office Scan, Panda Antivirus or McAfee and regularly scan your computer with an antivirus program.
Anti spyware :
Install and configure an up-to-dated anti spyware software in your network.
Updated Operating System :
Update your Windows based operating systems with the latest service packs, hot fixes and security patches.
Browser Security :
Raise the level of security of your web browsers.
Connectivity :
Computer networking sometimes considered to be complex and seems to hard to troubleshoot. The connectivity problems occur in the computer network due to the devices conflicts, outdated LAN card’s driver, faulty hardware, faulty cable or connectors and misconfigurations. To troubleshoot the connectivity related issues, you need to perform the following tasks.
Check the LEDs of your LAN card.
Update the driver of your LAN card.
Scan your computer for the viruses and spyware.
Check the UTP/STP cable, the both end of the cable should be properly inserted i.e. one end in the LAN card and one end in the hub/switch or router.
Check the configurations of the LAN card.
PING the destination computer and check the status.
If your problem is still not resolved, replace the LAN card and reconfigure it.
Maintenance :
Computer network availability and security is very critical for the businesses. Maintenance include the domain setup, dealing with the internal and external security threats, assigning IP addresses to the computes, enabling/disabling network services like DHCP, FTP SMTP, SNMP, taking data backup, adding/removing users, troubleshooting the software/hardware, configuring the firewall and implementing the security in the overall IT infrastructure. To perform the maintenance related tasks in your compute network, you need the perfect tools.
Troubleshooting :
You can troubleshoot the computer network related problems by using the right tools and techniques. Be default, Windows based operating systems offer the TCP/IP stack, which contains the troubleshooting and diagnostic utilities such as PING, IPCONFIG, Hostname, ARP, Telnet, NSLOOKUP, Tracert and many others. Pinging a network computer is the first troubleshooting step as it checks the connectivity with the destination computer. Additionally, you can use the other troubleshooting tools such as Ethereal, IP Sniffer, LanGuard, Packeteer and many others. These tools help to diagnose the cause of the problem and troubleshoot them.
Performance :
To get the optimized performance from your computer network, you need to perform the following actions on every computer of your network.
Use System Tools :
Delete Unnecessary Files
Update Device Drivers
Update BIOS
Uninstall Unused Programs
Update Operating System
Wireless Networking Security Tips
The following tips are very helpful in securing your wireless computer network.
Change the Default SSID
Change the Default Administrator’s password
Disable SSID broadcast.
Enable Mac Address Filtering
Assign Static IP address to the Network devices and computers.
Turn on and configure the firewall on every computer in your network.
Enable IPSec, SSL, Encryption, WPA and WPE according to your security requirements.
Computer networks are used to share the data and resources and for the communications. To get the optimized performance, data protection, maintenance, improved reliability and the security, every system administrator and network administrator should know the basic maintenance, troubleshooting and security techniques. Downtime is very dangerous for the critical network business applications and servers. In this article, you will learn some of the best networking tips and by using them you can get the optimized performance from your network.
Security :
A compute network is susceptible to the internet and external security related threats, which includes viruses, spyware, adware, Trojan horses, rootkits, web worms, intruders and hackers. To keep your network secure
Firewall :
Install and configure a software/hardware firewall on your gateway and all other computers in your network. Firewall is used monitor the inbound and outbound traffic and block the unauthorized access and hackers’ attacks.
Antivirus: Install antivirus software such as Norton Antivirus, Trend Micro Office Scan, Panda Antivirus or McAfee and regularly scan your computer with an antivirus program.
Anti spyware :
Install and configure an up-to-dated anti spyware software in your network.
Updated Operating System :
Update your Windows based operating systems with the latest service packs, hot fixes and security patches.
Browser Security :
Raise the level of security of your web browsers.
Connectivity :
Computer networking sometimes considered to be complex and seems to hard to troubleshoot. The connectivity problems occur in the computer network due to the devices conflicts, outdated LAN card’s driver, faulty hardware, faulty cable or connectors and misconfigurations. To troubleshoot the connectivity related issues, you need to perform the following tasks.
Check the LEDs of your LAN card.
Update the driver of your LAN card.
Scan your computer for the viruses and spyware.
Check the UTP/STP cable, the both end of the cable should be properly inserted i.e. one end in the LAN card and one end in the hub/switch or router.
Check the configurations of the LAN card.
PING the destination computer and check the status.
If your problem is still not resolved, replace the LAN card and reconfigure it.
Maintenance :
Computer network availability and security is very critical for the businesses. Maintenance include the domain setup, dealing with the internal and external security threats, assigning IP addresses to the computes, enabling/disabling network services like DHCP, FTP SMTP, SNMP, taking data backup, adding/removing users, troubleshooting the software/hardware, configuring the firewall and implementing the security in the overall IT infrastructure. To perform the maintenance related tasks in your compute network, you need the perfect tools.
Troubleshooting :
You can troubleshoot the computer network related problems by using the right tools and techniques. Be default, Windows based operating systems offer the TCP/IP stack, which contains the troubleshooting and diagnostic utilities such as PING, IPCONFIG, Hostname, ARP, Telnet, NSLOOKUP, Tracert and many others. Pinging a network computer is the first troubleshooting step as it checks the connectivity with the destination computer. Additionally, you can use the other troubleshooting tools such as Ethereal, IP Sniffer, LanGuard, Packeteer and many others. These tools help to diagnose the cause of the problem and troubleshoot them.
Performance :
To get the optimized performance from your computer network, you need to perform the following actions on every computer of your network.
Use System Tools :
Delete Unnecessary Files
Update Device Drivers
Update BIOS
Uninstall Unused Programs
Update Operating System
Wireless Networking Security Tips
The following tips are very helpful in securing your wireless computer network.
Change the Default SSID
Change the Default Administrator’s password
Disable SSID broadcast.
Enable Mac Address Filtering
Assign Static IP address to the Network devices and computers.
Turn on and configure the firewall on every computer in your network.
Enable IPSec, SSL, Encryption, WPA and WPE according to your security requirements.
Networking hardware
Networking hardware
Networking hardware typically refers to equipment facilitating the use of a computer network. Typically, this includes routers, switches, hubs, gateways, access points, network interface cards, Networking cables, network bridges, modems, ISDN adapters, firewalls and other related hardware.
The most common kind of networking hardware today is copper-based Ethernet adapters, helped largely by its standard inclusion on most modern computer systems. Wireless networking has become increasingly popular, however, especially for portable and handheld devices.
Other hardware prevalent within computer networking is datacenter equipment (such as file servers, database servers and storage areas), network services (such as DNS, DHCP, email etc) as well as other specific network devices such as content delivery.
Other diverse devices which may be considered Networking hardware include mobile phones, PDAs and even modern coffee machines. As technology grows and IP-based networks are integrated into building infrastructure and household utilities, network hardware becomes an ambiguous statement owing to the increasing number of 'network capable' endpoints.
Networking hardware typically refers to equipment facilitating the use of a computer network. Typically, this includes routers, switches, hubs, gateways, access points, network interface cards, Networking cables, network bridges, modems, ISDN adapters, firewalls and other related hardware.
The most common kind of networking hardware today is copper-based Ethernet adapters, helped largely by its standard inclusion on most modern computer systems. Wireless networking has become increasingly popular, however, especially for portable and handheld devices.
Other hardware prevalent within computer networking is datacenter equipment (such as file servers, database servers and storage areas), network services (such as DNS, DHCP, email etc) as well as other specific network devices such as content delivery.
Other diverse devices which may be considered Networking hardware include mobile phones, PDAs and even modern coffee machines. As technology grows and IP-based networks are integrated into building infrastructure and household utilities, network hardware becomes an ambiguous statement owing to the increasing number of 'network capable' endpoints.
Introduction to Firewall
INTRODUCTINO TO FIREWALL
Firewall is a first line of defense and protective barrier between your network and the outer world. It can be a software or hardware and it is configured and attached with the gateway computer. It encrypts, filters, monitors, permits or denies all the network traffic. A system without the implementation of the firewall can easily be attacked by the viruses, hackers, intruders, unauthorized access and other internal and external threats. It regulates the traffic between the computer network and the internet. It protects the resources of the private network from the internal and external threats.
Windows XP Professional has built-in firewall software that allows the users to filter the incoming and outgoing traffic by applying different rules. The rules can be based on the IP addresses of the source and destination, port number, domain names and specific applications and protocols such as FTP, HTTP, Remote desktop, Telnet, SMTP, POP3 and Https etc. A firewall works closely with the router and many routers has the built-in firewall. The common functionalities include packet filtering, application gateway, proxy server and circuit relay.
Firewall Features
The common features of a firewall program include the following.
Packet filtering
Ports blocking and scanning
Web filtering
URL Screening
Web caching
User blocking
Domain blocking
Antivirus
Spam Filtering
Email Scanning
Network Access Rules
Network Address Translation (NAT)
User Authentication
Intrusion Protection
Network Activity Monitoring
Types of Firewall
Firewall can be categorized into the following two major categories.
Software Firewall
There are many software firewall products that are usually installed and configured on the Server computer. The most common software firewall includes Zone Alarm, Wingate, Barracuda spam firewall, Symantec Norton Personal Firewall, McAfee Personal Firewall Plus and Sygate® Personal Firewall PRO.
Hardware Firewall
A hardware firewall is a dedicated device that is usually attached with the gateway computer. Many routers provide have built-in firewall features. It filters the network traffic and blocks the unwanted traffic.
Firewall is a first line of defense and protective barrier between your network and the outer world. It can be a software or hardware and it is configured and attached with the gateway computer. It encrypts, filters, monitors, permits or denies all the network traffic. A system without the implementation of the firewall can easily be attacked by the viruses, hackers, intruders, unauthorized access and other internal and external threats. It regulates the traffic between the computer network and the internet. It protects the resources of the private network from the internal and external threats.
Windows XP Professional has built-in firewall software that allows the users to filter the incoming and outgoing traffic by applying different rules. The rules can be based on the IP addresses of the source and destination, port number, domain names and specific applications and protocols such as FTP, HTTP, Remote desktop, Telnet, SMTP, POP3 and Https etc. A firewall works closely with the router and many routers has the built-in firewall. The common functionalities include packet filtering, application gateway, proxy server and circuit relay.
Firewall Features
The common features of a firewall program include the following.
Packet filtering
Ports blocking and scanning
Web filtering
URL Screening
Web caching
User blocking
Domain blocking
Antivirus
Spam Filtering
Email Scanning
Network Access Rules
Network Address Translation (NAT)
User Authentication
Intrusion Protection
Network Activity Monitoring
Types of Firewall
Firewall can be categorized into the following two major categories.
Software Firewall
There are many software firewall products that are usually installed and configured on the Server computer. The most common software firewall includes Zone Alarm, Wingate, Barracuda spam firewall, Symantec Norton Personal Firewall, McAfee Personal Firewall Plus and Sygate® Personal Firewall PRO.
Hardware Firewall
A hardware firewall is a dedicated device that is usually attached with the gateway computer. Many routers provide have built-in firewall features. It filters the network traffic and blocks the unwanted traffic.
Sunday, June 7, 2009
Headphones
Going Wireless - Headphones
Wireless headphones with good sound quality have only been widely available and affordable for a few years. If you're like me and are constantly breaking the wires on your ordinary headphones, wireless ones provide a nice relief. Experts agree that wireless headphones don't match the sound quality of traditional ones, but for casual listening, the convenience of wireless is often worth the occasional hissing noise you may hear. Four types of wireless headphones exist:
- FM radio frequency (RF) - typically the most affordable option, these units simply broadcast radio signals rather than establishing a point-to-point wireless connection
- Bluetooth - especially popular for connecting with cell phones
- infrared - designed for home theater systems, these units support very good sound quality but their range is limited to a single room
- Wi-Fi - capable of longer range transmissions than the others, Wi-Fi wireless headphone technology is still maturing
Network Adapters
Network Adapters
The first piece of hardware that I want to discuss is a network adapter. There are many different names for network adapters, including network cards, Network Interface Cards, NICs. These are all generic terms for the same piece of hardware. A network card’s job is to physically attach a computer to a network, so that the computer can participate in network communications.
The first thing that you need to know about network cards is that the network card has to match the network medium. The network medium refers to the type of cabling that is being used on the network. Wireless networks are a science all their own, and I will talk about them in a separate article.
At one time making sure that a network card matched the network medium was a really big deal, because there were a large number of competing standards in existence. For example, before you built a network and started buying network cards and cabling, you had to decide if you were going to use Ethernet, coaxal Ethernet, Token Ring, Arcnet, or one of the other networking standards of the time. Each networking technology had its strengths and weaknesses, and it was important to figure out which one was the most appropriate for your organization.
Today, most of the networking technologies that I mentioned above are quickly becoming extinct. Pretty much the only type of wired network used by small and medium sized businesses is Ethernet. You can see an example of an Ethernet network card, shown in Figure A.
Figure A: This is what an Ethernet card looks like
Modern Ethernet networks use twisted pair cabling containing eight wires. These wires are arranged in a special order, and an RJ-45 connecter is crimped onto the end of the cable. An RJ-45 cable looks like the connector on the end of a phone cord, but it’s bigger. Phone cords use RJ-11 connectors as opposed to the RJ-45 connectors used by Ethernet cable. You can see an example of an Ethernet cable with an RJ-45 connector, shown in Figure B.
Figure B: This is an Ethernet cable with an RJ-45 connector installed
Hubs and Switches
As you can see, computers use network cards to send and receive data. The data is transmitted over Ethernet cables. However, you normally can’t just run an Ethernet cable between two PCs and call it a network.
In this day and age of high speed Internet access being almost universally available, you tend to hear the term broadband thrown around a lot. Broadband is a type of network in which data is sent and received across the same wire. In contrast, Ethernet uses Baseband communications. Baseband uses separate wires for sending and receiving data. What this means is that if one PC is sending data across a particular wire within the Ethernet cable, then the PC that is receiving the data needs to have the wire redirected to its receiving port.
You can actually network two PCs together in this way. You can create what is known as a cross over cable. A cross over cable is simply a network cable that has the sending and receiving wires reversed at one end, so that two PCs can be linked directly together.
The problem with using a cross over cable to build a network is that the network will be limited to using no more and no less than two PCs. Rather than using a cross over cable, most networks use normal Ethernet cables that do not have the sending and receiving wires reversed at one end.
Of course the sending and receiving wires have to be reversed at some point in order for communications to succeed. This is the job of a hub or a switch. Hubs are starting to become extinct, but I want to talk about them any way because it will make it easier to explain switches later on.
There are different types of hubs, but generally speaking a hub is nothing more than a box with a bunch of RJ-45 ports. Each computer on a network would be connected to a hub via an Ethernet cable. You can see a picture of a hub, shown in Figure C.
Figure C: A hub is a device that acts as a central connection point for computers on a network
A hub has two different jobs. Its first job is to provide a central point of connection for all of the computers on the network. Every computer plugs into the hub (multiple hubs can be daisy chained together if necessary in order to accommodate more computers).
The hub’s other job is to arrange the ports in such a way so that if a PC transmits data, the data is sent over the other computer’s receive wires.
Right now you might be wondering how data gets to the correct destination if more than two PCs are connected to a hub. The secret lies in the network card. Each Ethernet card is programmed at the factory with a unique Media Access Control (MAC) address. When a computer on an Ethernet network transmits data across an Ethernet network containing PCs connected to a hub, the data is actually sent to every computer on the network. As each computer receives the data, it compares the destination address to its own MAC address. If the addresses match then the computer knows that it is the intended recipient, otherwise it ignores the data.
As you can see, when computers are connected via a hub, every packet gets sent to every computer on the network. The problem is that any computer can send a transmission at any given time. Have you ever been on a conference call and accidentally started to talk at the same time as someone else? This is the same thing that happens on this type of network.
When a PC needs to transmit data, it checks to make sure that no other computers are sending data at the moment. If the line is clear, it transmits the necessary data. If another computer tries to communicate at the same time though, then the packets of data that are traveling across the wire collide and are destroyed (this is why this type of network is sometimes referred to as a collision domain). Both PCs then have to wait for a random amount of time and attempt to retransmit the packet that was destroyed.
As the number of PCs on a collision domain increases, so does the number of collisions. As the number of collisions increase, network efficiency is decreased. This is why switches have almost completely replaced hubs.
A switch, such as the one shown in Figure D, performs all of the same basic tasks as a hub. The difference is that when a PC on the network needs to communicate with another PC, the switch uses a set of internal logic circuits to establish a dedicated, logical path between the two PCs. What this means is that the two PCs are free to communicate with each other, without having to worry about collisions.
Figure D: A switch looks a lot like a hub, but performs very differently
Switches greatly improve a network’s efficiency. Yes, they eliminate collisions, but there is more to it than that. Because of the way that switches work, they can establish parallel communications paths. For example, just because computer A is communicating with computer B, there is no reason why computer C can’t simultaneously communicate with computer D. In a collision domain, these types of parallel communications would be impossible because they would result in collisions.
Monday, May 11, 2009
Home Network Storage System
Do You Use a Home Network Storage System?
YesNo - but am definitely considering itNo - not considering or don't need itN/A - what's network storage?
Network storage allows you to conveniently save and restore data across devices on a local network. Originally a high-end feature only businesses could afford, network storage systems are now also readily available for personal and home use. Types of network storage products include NAS drives and server software like FreeNAS.
Participate in our poll (see above and right) to see where some of our other readers stand on evaluating or using network storage systems.
What is Windows 7 DirectAccess?
DirectAccess is a new feature of Microsoft Windows 7 and Windows Server 2008 R2. DirectAccess eliminates the need for users to set up a separate VPN connection as all of the required support is integrated into the operating system. It is designed for remote client access to corporate servers and networks over the Internet.
Those with computers running operating systems other than Windows 7 cannot use DirectAccess, of course.
YesNo - but am definitely considering itNo - not considering or don't need itN/A - what's network storage?
Network storage allows you to conveniently save and restore data across devices on a local network. Originally a high-end feature only businesses could afford, network storage systems are now also readily available for personal and home use. Types of network storage products include NAS drives and server software like FreeNAS.
Participate in our poll (see above and right) to see where some of our other readers stand on evaluating or using network storage systems.
What is Windows 7 DirectAccess?
DirectAccess is a new feature of Microsoft Windows 7 and Windows Server 2008 R2. DirectAccess eliminates the need for users to set up a separate VPN connection as all of the required support is integrated into the operating system. It is designed for remote client access to corporate servers and networks over the Internet.
Those with computers running operating systems other than Windows 7 cannot use DirectAccess, of course.
PC Components
Introduction to PC Components Here you will learn computer hardware tutorials introduction, basic pc components, networking devices, ram, vga, monitor and printer etc. Computer hardware is the physical part of the computer including the digital circuits inside the computer as opposed to the software that carry out the computing instructions. The hardware of a computer is unlikely to change frequently unless due to the crash or for upgrading them. The devices that is capable of storing, executing system instructions and controlling other logical outputs.
Hardware comprises all of the physical part of the computer such as Monitor, CPU, motherboard, ram, CD-Rom, printer, scanner, hard disk, flash drive (AKA pen drive), processor, pci buses, floppy disk, power supply, VGA card, sound card, network interface card, peripherals, joystick, mouse, keyboard, foot pedal, computer fan, camera, headset and others
On the other hard software is a logical part of a computer and is used to carry out the instructions, storing, executing and developing other software programs. A typical PC consists of a case or chassis in the desktop or tower case and these components.
Motherboard
• CPU
• Computer Fan
• RAM
• BIOS
• Digital Circuitry
• Computer Fan
• PCI Slots
PC Buses
• PCI
• USB
• Hyper-transport
• AGP
• ISA
• EISA
• VLB
Media
• CD-Rom
• DVD-Rom
• Combo box
• Joystick
• BD-Rom drive
Internal storage
• Hard disk (ATA & SATA)
• Data array controller
• Floppy disk
Other Peripheral Devices
• Mouse
• Modems
• Digital Camera
• Sound, Video Cards
• Printer
Output Devices
• Printer
• Scanner
• Monitor
• Speakers
• Headset
• Video output devices
CPU (Central Processing Unit): CPU or central processing unit relates to a specific or processor. The performance of the computer is determined by the CPU chip (processor speed) and the other computer circuitry. Currently, the Pentium chip (processor) is the most popular even though there are other chips available in the market today such as AMD, Motorola and others. The clocks speed becomes most important factor in determining the performance of a computer. The motherboard contains the hardware circuitry and connections that allow the different hardware components of the PC to interact and communicate with each other. Most computer software is being developed for the latest processors so it would be difficult to use the older systems.
Hard Disk Drives – Disk drive is the mechanism to run the disks. All disks need a drive to get the information, read it and put it back to the disks. Hard disk is used to store the data permanently. Often the terms disk and drive used to describe the same thing but it should be clear that a disk is a storage device.
Modem – A modem is used for the modulation and demodulation of the data that is transferred through the modem and the telephone lines. Modem translates the data from digital to analog from analog to digital. Because on the telephone lines data can travel in the form of the analog signals and in the computer data transmits in the form of digital signals. Modems are measured by the speed which is called baud rate. The typical baud rate is 56Kb.
Keyboard – The keyboard is used to type something or input information to the computer. There are different designs and models of the keyboards in the market. The most common layout of the keyboard is QWERTY layout. A standard keyboard has 101 keys and embedded keys.
Video cards - Video cards allow computer to display video, graphics and animation. Some video cards allow computers to display television. A video card with a digital video camera allows users to produce live video. A high speed broadband internet connection is required to watch the videos on net.
Network cards: Network interface cards allow PCs to connect with each other and communicate. Every network computer is required to have a NIC card. NIC cards are required both in wired and wireless networking.
Cables: There are two broad types of cables internal cables, which are embedded on the mother board circuit that performs the communication between the devices and CPU. The other types of the cables are the network cables like coaxial cable, CAT 5, Ethernet cables. These cables are used for the communication purposes between the devices or computers.
Memory – Memory is the one of the important piece of the hardware. Sometimes memory chip memory is confused with the hard disk memory. Sometimes unallocated space of the hard disk is used as virtual memory also known as page file. This type of memory is a temporary memory and is used actual memory is less and requires some additional memory to perform a specific task.
RAM (Random Access Memory) RAM is a memory that is being used by the computer to store the information temporarily. For example when some work is performed on some applications that work is temporarily stored in the RAM. More RAM in the computer more faster computer works. Today at least requirement of a modern PC is 64 RAM. RAM is in the form of a chip and different vendors have developed the RAM of different capacities.
Mouse – Every modern computer requires a mouse for faster operations. Generally a mouse has two buttons left and right to perform different functions. One type of the mouse has a round ball under the bottom. Another type of the mouse use optical system to track the movement of the mouse.
Monitors – The monitor is used to display the information on the screen. All the activities of a computer, functions and tasks are seen on the computer screen and this is called outputting information. Monitors come in many sizes and shapes, monochrome or full colors. Today most computers use LCD screens. It is light weight and consumes less power as compared to the monitors.
Printers – The printer takes the information from the PC and transfers it to the paper of different sizes, which are placed in the printer device. There are three basic types of a printer such as dot matrix, inkjet and laser.
Scanners - Scanners allow you to transfer pictures and photographs to your computer. A scanner is used to scan the images and pictures. You can then send the image to someone, modify it or take a print out of it. With optical character recognition software you can convert printed documents into the text that you can use in the word processor.
Digital camera- You can take the digital photographs with the digital cameras. The images are stored on the memory chip of the digital cameras and you can transfer them to your computer with the USB drive.
Case – Case or casing covers the whole computer’s circuitry. There are two types of casings desktop and tower casing. There is room inside the casing to add or remove components. Cases come in many sizes like desktop, mini, midi and tower. There are some additional empty slots inside the cases such as IDE, USB, ASI, PCI and firewire slots.
Cards – Cards are the hardware components that are added to the computer to increase their functionalities and capabilities.
Sound cards produce the sound like music and voice. The older cars were 8, 16 and then 32 bits.Color cards allow computers to produce colors. Initially there were 2, 4 and then 16 bits. The main types of the graphic cards are EGA, VGA and SGA. The 32 cards are the standard to display almost billions of the colors on the monitor
Sunday, May 10, 2009
FIREWALL
Basically, a firewall is a barrier to keep destructive forces away
from one's property. In fact, that's why it's called a firewall. Its job
is similar to a physical firewall that keeps a fire from spreading
from one area to the next.
Firewall is simply a program or hardware device that filters the
information coming through the Internet connection into private
network or computer system . If an incoming packet of information
is flagged by the filters, it is not allowed through.
With a firewall in place, the landscape is much different. A
company will place a firewall at every connection to the Internet
(for example, at every T1 line coming into the company). The
firewall can implement security rules. For example, one of the security rules inside the company
might be:
Out of the 500 computers inside this company, only one of them is permitted to receive public
FTP traffic. FTP connections only to that one computer are allowed and prevent them on all
others.
A company can set up rules like this for FTP servers, Web servers, Telnet servers and so on. In
addition, the company can control how employees connect to Web sites, whether files are
allowed to leave the company over the network and so on. A firewall gives a company
tremendous control over how people use the network.
from one's property. In fact, that's why it's called a firewall. Its job
is similar to a physical firewall that keeps a fire from spreading
from one area to the next.
Firewall is simply a program or hardware device that filters the
information coming through the Internet connection into private
network or computer system . If an incoming packet of information
is flagged by the filters, it is not allowed through.
With a firewall in place, the landscape is much different. A
company will place a firewall at every connection to the Internet
(for example, at every T1 line coming into the company). The
firewall can implement security rules. For example, one of the security rules inside the company
might be:
Out of the 500 computers inside this company, only one of them is permitted to receive public
FTP traffic. FTP connections only to that one computer are allowed and prevent them on all
others.
A company can set up rules like this for FTP servers, Web servers, Telnet servers and so on. In
addition, the company can control how employees connect to Web sites, whether files are
allowed to leave the company over the network and so on. A firewall gives a company
tremendous control over how people use the network.
Firewalls use one or more of three methods to control traffic flowing in and out of the network:
• Packet filtering - Packets (small chunks of data) are analyzed against a set of filters.
Packets that make it through the filters are sent to the requesting system and all others
are discarded.
• Proxy service - Information from the Internet is retrieved by the firewall and then sent
to the requesting system and vice versa.
• Stateful inspection - A newer method that doesn't examine the contents of each packet
but instead compares certain key parts of the packet to a database of trusted
information. Information traveling from inside the firewall to the outside is monitored
for specific defining characteristics, and then incoming information is compared to these
characteristics. If the comparison yields a reasonable match, the information is allowed
through. Otherwise it is discarded.
Making the Firewall Fit:
Firewalls are customizable. This means that the user can add or remove filters based on several
conditions. Some of these are:
• IP addresses - Each machine on the Internet is assigned a unique address called an IP
address . IP addresses are 32-bit numbers, normally expressed as four "octets" in a
"dotted decimal number." A typical IP address looks like this: 216.27.61.137. For
example, if a certain IP address outside the company is reading too many files from a
server, the firewall can block all traffic to or from that IP address.
• Domain names - Since it is hard to remember the string of numbers that make up an IP
address and because IP addresses sometimes need to change, all servers on the Internet
also have human-readable names, called domain names . For example, it is easier for
most users to remember www.howstuffworks.com than it is to remember 216.27.61.137.
A company might block all access to certain domain names, or allow access only to
specific domain names.
• Protocols - The protocol is the pre-defined way that someone who wants to use a
service talks with that service. The "someone" could be a person, but more often it is a
computer program like a Web browser. Protocols are often text, and simply describe
how the client and server will have their conversation. The http in the Web's protocol.
• Packet filtering - Packets (small chunks of data) are analyzed against a set of filters.
Packets that make it through the filters are sent to the requesting system and all others
are discarded.
• Proxy service - Information from the Internet is retrieved by the firewall and then sent
to the requesting system and vice versa.
• Stateful inspection - A newer method that doesn't examine the contents of each packet
but instead compares certain key parts of the packet to a database of trusted
information. Information traveling from inside the firewall to the outside is monitored
for specific defining characteristics, and then incoming information is compared to these
characteristics. If the comparison yields a reasonable match, the information is allowed
through. Otherwise it is discarded.
Making the Firewall Fit:
Firewalls are customizable. This means that the user can add or remove filters based on several
conditions. Some of these are:
• IP addresses - Each machine on the Internet is assigned a unique address called an IP
address . IP addresses are 32-bit numbers, normally expressed as four "octets" in a
"dotted decimal number." A typical IP address looks like this: 216.27.61.137. For
example, if a certain IP address outside the company is reading too many files from a
server, the firewall can block all traffic to or from that IP address.
• Domain names - Since it is hard to remember the string of numbers that make up an IP
address and because IP addresses sometimes need to change, all servers on the Internet
also have human-readable names, called domain names . For example, it is easier for
most users to remember www.howstuffworks.com than it is to remember 216.27.61.137.
A company might block all access to certain domain names, or allow access only to
specific domain names.
• Protocols - The protocol is the pre-defined way that someone who wants to use a
service talks with that service. The "someone" could be a person, but more often it is a
computer program like a Web browser. Protocols are often text, and simply describe
how the client and server will have their conversation. The http in the Web's protocol.
Some common protocols that you can set firewall filters for include:
o IP (Internet Protocol) - the main delivery system for information over the
Internet
o TCP (Transport Control Protocol) - used to break apart and rebuild information
that travels over the Internet
o HTTP (Hyper Text Transfer Protocol) - used for Web pages
o FTP (File Transfer Protocol) - used to download and upload files
o UDP (User Datagram Protocol) - used for information that requires no response,
such as streaming audio and video
o ICMP (Internet Control Message Protocol) - used by a router to exchange the
information with other routers
o SMTP (Simple Mail Transport Protocol) - used to send text-based information (email)
o SNMP (Simple Network Management Protocol) - used to collect system
information from a remote computer
o Telnet - used to perform commands on a remote computer
o IP (Internet Protocol) - the main delivery system for information over the
Internet
o TCP (Transport Control Protocol) - used to break apart and rebuild information
that travels over the Internet
o HTTP (Hyper Text Transfer Protocol) - used for Web pages
o FTP (File Transfer Protocol) - used to download and upload files
o UDP (User Datagram Protocol) - used for information that requires no response,
such as streaming audio and video
o ICMP (Internet Control Message Protocol) - used by a router to exchange the
information with other routers
o SMTP (Simple Mail Transport Protocol) - used to send text-based information (email)
o SNMP (Simple Network Management Protocol) - used to collect system
information from a remote computer
o Telnet - used to perform commands on a remote computer
Saturday, May 9, 2009
Networking hardware
Networking hardware typically refers to equipment facilitating the use of a computer network. Typically, this includes routers, switches, hubs, gateways, access points, network interface cards, Networking cables, network bridges, modems, ISDN adapters, firewalls and other related hardware.
The most common kind of networking hardware today is copper-based Ethernet adapters, helped largely by its standard inclusion on most modern computer systems. Wireless networking has become increasingly popular, however, especially for portable and handheld devices.
Other hardware prevalent within computer networking is datacenter equipment (such as file servers, database servers and storage areas), network services (such as DNS, DHCP, email etc) as well as other specific network devices such as content delivery.
Other diverse devices which may be considered Networking hardware include mobile phones, PDAs and even modern coffee machines. As technology grows and IP-based networks are integrated into building infrastructure and household utilities, network hardware becomes an ambiguous statement owing to the increasing number of 'network capable' endpoints.
List of Networking hardware vendors
Networking hardware typically refers to equipment facilitating the use of a computer network. Typically, this includes routers, switches, access points, network interface cards and other related hardware. This is a comprehensive list of all vendors who produce Network Hardware vendors.
Routers
The largest Routing Vendors in the world by revenue, according to Gartner Dataquest.
The largest Routing Vendors in the world by revenue, according to Gartner Dataquest.
Switches
The largest Switch vendors in the world by revenue and portcount, according to Gartner Dataquest and swith is intelligent device.
The largest Switch vendors in the world by revenue and portcount, according to Gartner Dataquest and swith is intelligent device.
Wireless
Atheros
Cisco
D-Link
Linksys
Proxim
Tall Umbrella
Tropos
Xirrus
ZyXEL
Network interface cards
Cisco
D-Link
Intel
Realtek
Cisco
D-Link
Intel
Realtek
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