My Netwok Dictionary

This article explains how to select the root bridge in an STP network. The first decision taken by all switches in the network is to identify the root bridge. The position of the root bridge in a network affects the flow of traffic.

When the switch is turned on, use the spanning tree algorithm to identify the root bridge. BPDUs are sent to the bridge ID (BID). The IDB consists of a bridge priority that takes a default value of 32768 and the switch MAC address. By default, BPDUs are sent every two seconds. Read the rest of this entry »

The cable access router Cisco uBR905 offers the possibility to access a high speed network to residential users, small office and home office (SOHO) using the cable television system.

The router has an interface uBR905 coaxial cable, or F-connector that plugs directly into the cable system. The coaxial cable and F connector used to connect the router and the cable system. Read the rest of this entry »

The structured cabling is a systematic focus of the wiring. It is a method to create a system of wiring organized that easily can be understood for the installers, administrators of network and any another technician that work with cables.

There are three rules to help ensure the effectiveness and efficiency in the projects of design of the wiring structured. The first rule is to find a complete solution for connectivity. An optimal solution for secure network connectivity includes all the systems that have been designed to connect, build, manage and identify the cables in the systems of cabling structured. Read the rest of this entry »

The optical fiber cable is unaffected by external noise sources that cause problems in copper media because stray light can not enter the fiber except at the end of the transmitter. The mantle is covered by a cushioning material and an outer jacket that prevents light from entering or leaving the cable.

Furthermore, the transmission of light in the fiber cable does not generate interference that affects the transmission any other fiber. This means that fiber is the problem of crosstalk that does have copper media. In fact, the quality of optical fiber links is so good that by recent standards for Gigabit and 10 Gigabit Ethernet provide transmission distances far exceed the traditional range of 2 kilometers from the original Ethernet. Optical fiber transmission allows the use of the Ethernet protocol in Metropolitan Area Networks (MANs) and Wide Area Networks (WAN). Read the rest of this entry »

Now the difference between routers and switches are becoming increasingly blurred, multi-layer routers and switches can realize the function of switching and routing between them there are different? What are their characteristics? How best to choose according to application requirements?

First, the traditional switches and routers:

Ordinary switches work in the Open Systems Interconnection (OSI) seven layer model of the second layer, data link layer Exchange for media access control (MAC) address based on the data stream to identify each packet’s source MAC address of a destination site, providing cheap, high-bandwidth network connections, but the ability to control packets are restrictions in the broadcasting area; routers work in the OSI seven layer model of the third layer, network layer, the data stream to identify the source and destination network address, control, limited the ability of the packet destination address the source of a pair, built-in routing protocols, while with large-capacity cache capacity, usually by routing software interconnection.

Ordinary switches and routers have some of their own deficiencies. If routers need to have very strong processor, its enormous routing table delays in the network, causing slow forward, and expensive, often become a bottleneck restricting high-speed transmission network; in common Layer 2 switch because only One purpose of reading the source MAC address, did not get a higher level packet information, which limited the exchange function, the main data stream does not have the necessary control. Read the rest of this entry »

1. Use of personal digital assistant network:

Personal Digital Assistant Network (PdaNet) is a mobile phone and the computer can be established between connection tools. It is easy to use and provides a free version can be started. The only downside is that the free version will block access to security websites. You can browse the site, but all security-related content will be locked. The software can support the operation of security caused by phone system, Blackberry devices, Windows Mobile devices and iPhone. Read the rest of this entry »

Introduction to Netstat

Netstat is a tool to determine the TCP connections are active on the machine where the command is enabled and thus list all the ports TCP and UDP open on the computer.

The command “netstat” also provides statistics on a number of protocols (Ethernet, IPv4, TCP, UDP, ICMP and IPv6). Read the rest of this entry »

“Ping” (short for Packet Internet Groper) is without doubt one of the tools of network administration best known. Yet this is one of the most simple since it allows, through the sending packets to verify if a remote machine responds and, by extension, it is accessible via the network.

The ping tool allows to diagnose network connectivity with a command like:

ping name.of.machine

name.of.machine represents the IP address of the machine or its name. It is usually best at first to test with the IP address of the machine. Read the rest of this entry »

Introduction to Traceroute

Traceroute is a tool for diagnosing networks, present on most operating systems, to determine the path followed by a package. The traceroute command allows to draw a map of the routers between a source machine and target machine. The traceroute command differs between operating systems.

Under the systems UNIX / Linux , the traceroute command is as follows:
traceroute name.of.machine

Under the systems Windows , the traceroute command is as follows:
tracert name.of.machine Read the rest of this entry »

IPerf is a command line program for measuring the performance of networks. JPerf is developed in a Java graphical user interface for IPerf. This guide describes the measurement of the bandwidth of networks by JPerf 2.0.2.

The Java application JPerf runs on Windows, Linux and Apple Mac OS X. For a measurement there are always two networked stations required. As long as both stations are to build an IP connection between the leaves, the type of network is irrelevant. The measurement may be in the local area network (LAN) and over the Internet (ADSL, VDSL, Cable Internet and UMTS) and is also carried out wireless internet access.

JPerf does not for the measurements on the hard disk. The performance of the disk is thus not one in the measurements. In practice, the copying of files over the network that is always slower than the JPerf identified with values.

The free program can be downloaded at Google Code. Read the rest of this entry »