My Netwok Dictionary

Network administrators can troubleshoot switched networks efficiently after learning the techniques and adapt to the needs of the company. Experience is the best way to improve these capabilities.

Some situations troubleshoot VLAN-related problems are most common. Each of these situations provides an analysis of the problem and its subsequent resolution. By using appropriate specific commands and collecting meaningful information from the results, we can complete the process of troubleshooting.

Situation One: You can not establish a trunk between a switch and a router. Where there are difficulties with a trunk connection between a switch and a router, consider the following possible causes: Read the rest of this entry »

When using a local area network, the aim is usually to provide an environment that makes the network transparent to users. An important step is keeping vital data such as information of the user accounts are synchronized across all machines. This gives users the freedom to move from machine to machine without the inconvenience of having to remember different passwords and copy data from one machine to another.

The data are centrally stored need not be replicated as long as a means of accessing them from a node connected to the network. By storing important administrative information centrally, is achieved by ensuring the consistency of these data, greater flexibility allowing users to move from node to node in a transparent manner and make life much easier for the administrator having to maintain only one copy individual information. Read the rest of this entry »

This article describes three methods of data used in a network. The most common form of communication is done by unicast transmission. In a unicast transmission, a transmitter tries to communicate with a receiver. Another way to communicate is called multicast transmission. Multicast transmission occurs when a transmitter is communicating with only a subset or segment group.

The last form of communication is sent in broadcast. The broadcast transmission occurs when a transmitter is to communicate with all receivers in the network. The server station sends a message and all found in the segment receive the message. Read the rest of this entry »

Dynamic host configuration protocol (DHCP) is the successor of BOOTP. As opposed to the BOOTP, the DHCP permits that the host one obtain the direction IP of dynamic form without the administrator of network have that to configure an individual profile for each device. All that is required to use DHCP is a defined range of IP addresses by DHCP server. As hosts come online, communicate with the DHCP server and requests an address. The DHCP server chooses an address and leases them to the host. With DHCP, the entire configuration of the network can be obtained in a message. This includes all data provided by the BOOTP message plus a leased IP address and subnet mask.

The main advantage is that the BOOTP DHCP is that it allows users to be mobile. This mobility allows users to change network connections freely from one place to another. It is no longer necessary to maintain a fixed profile of each device connected to the network as in BOOTP system. The importance of this advance of DHCP is its ability to lease an IP address to a device and then claim that IP address to another user after the first releases. This does it mean that DHCP can assign IP addresses available to anyone connected to the network. Read the rest of this entry »

Ethernet to grow 10 to 100 and 1000 Mbps, it was necessary to make each technology could operate with others, to point interfaces 10, 100 and 1000 could connect directly. We developed a process called auto-negotiation of the speed in half duplex or full duplex. Specifically, at the time of introduction of Fast Ethernet, the standard method included an automatically configure a given interface to make it consistent with the speed and capabilities interface at the other end of the link.

This process defines how the interfaces at the ends of the link can automatically negotiate a configuration offering the highest level of joint performance. It has the additional advantage of involving only the lower part of the physical layer. The 10BASE-T required that each station transmits a link pulse every 16 milliseconds, provided that the station was not transmitting a message. Read the rest of this entry »

The Cisco products support the latest technology of Virtual Private Networks (VPN). The VPN is a service that offers dependable and protected connectivity in a shared public network communications such the same as the Internet. The VPN conserve the same politics of security and administration as a private network. They are the most economical way to establish a connection point-to-point between remote users and the network of a client of the firm.

Here are the three main types of VPN:

• VPN Access: The VPN of access offer remote access to a mobile worker and a small office /home office (SOHO), to the headquarters of the internal or external network through a shared infrastructure. The VPN of access use analog technologies, dialup, ISDN, digital subscriber line (DSL), cable and mobile IP to provide secure connections to mobile users, employees at remote and branch offices.

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The bandwidth is defined like the quantity of information that can flow through a connection of network in a period given is essential to understand the concept of bandwidth networking to study for the following four reasons:

1. The bandwidth is finite. In other words, independently of the middle that is utilized for build the network, limits for the capacity of the network exist to transport information. The bandwidth is limited by the laws of physics and the technologies used to place the information in the media. For example, the bandwidth of a conventional modem is limited to about 56 kbps for the physical properties of the twisted pair telephone lines and modem technology. However, the technologies use the same DSL twisted pair telephone wires, yet offers DSL bandwidth that is much larger than conventional modems. This shows that it is sometimes difficult to define the limits imposed by the same laws of physics. The optical fiber has the potential physical provide a virtually unlimited band width. Still, the bandwidth of optical fiber can not be exploited in full, pending technologies are developed to realize their potential. Read the rest of this entry »

It happened in the development of Gigabit Ethernet, the increase in the speed comes with higher requirements. A shorter bit time resulting from a higher speed requires special considerations. In the 10 GbE transmissions, each data bit lasts 0.1 nanoseconds. This means there would be 1000 bits of data at the same time GbE bit a bit of data in a data stream of 10-Mbps Ethernet. Due to the short duration of data bit 10 GbE; it is often difficult to separate one data bit of noise. The transmission of 10 GbE data depend on the exact timing of the data bit to separate the effects of noise on the physical layer. This is the purpose of synchronization.

In response to these problems of synchronization, the bandwidth and the relationship between signal and noise, 10 Gigabit Ethernet uses two different steps of encoding. By using codes to represent user data, data transmission occurs more efficiently. The encoded data provides synchronization, efficient use of bandwidth and best features of the Relationship between signal and noise. Read the rest of this entry »

A wireless network can be comprised of only two devices. The nodes can be simple workstations of desktop or handheld computers. It equipped with not wireless, a network can be established ‘ad hoc’ comparable to a wired network peer to peer. Both devices work as servers and clients in this environment. Although it provides connectivity, security is minimal, as the transfer rate. Another problem with this type of network is compatibility. Many times, the NIC from different manufacturers are not compatible.

To solve the compatibility problem is usually installed an access point (AP) to act as a central hub for infrastructure mode WLAN. The AP is connected by wiring to the wired LAN to provide Internet access and connectivity to the wired network. The AP is equipped with antennas and provides wireless connectivity to a specific area that receives the name of cell. According to the structural composition of the place where the AP is installed, the size and gain of the antennas, the size of the cell can vary greatly. Generally, the range is 91.44 meters to 152.4 meters (300 to 500 feet). To service larger areas, you can install multiple access points with a certain degree of overlap. Read the rest of this entry »

The Internet is the most important data network in the world. The Internet is collected of a big quantity of interconnected small and large networks. Individual computers are the sources and destinations of information through the Internet. Wireless Internet connection can be divided into physical connection and logical connection applications.

A physical connection is connecting an adapter card, such as a modem or a NIC, from a PC to a network. The physical connection is utilized to transfer the signs among the different PC inside the network of local area (LAN) and toward the remote devices that are found on the Internet. Read the rest of this entry »