Anyone who wants to build a small network in his office, his agency or perhaps even at home, needs a certain basic understanding of how computer networks work. Then he is also able to better understand, weigh and implement different solutions. If communication between computers and devices is to be ensured as smoothly as possible, they must be interconnected. This can be done either by cable or by radio.
Questions about planning your own network
A logical connection must then also be established on this physical connection: This includes, among other things, questions such as the data to be transferred, or which computers may communicate with one another at all. At this logical level, the actual programs are used that allow the user to select and work with the data. Since this layer construction has been used as a standard for decades, nowadays all known networks are adhering to it, and a mixture of different components usually works very well.
When users are asked what they want to use a network, they will probably think of their Word and Excel files and related print jobs, as well as the e-mail messages. Access to the Internet should also be possible from all computers on the network. As a matter of principle, a user is then offered quite different possibilities for his own network to establish a connection between the devices. Certain connections are, of course, dictated by the type of device.
Structured connection and fast server
Finally, no user would need to connect his smartphone to the office network using cables. For the logical connection to the network and thus also for the applications that are used in it, no matter how a device accesses the network, the person responsible must of course establish a difference between a cable- and a radio-based connection of the network Devices. Often building conditions determine which connection can be used and which do not. Nevertheless, users should consider very well beforehand whether it is perhaps not more sensible to optimize the structural conditions, than to permanently annoy an unstable network. If you want to choose between different connection types and possibilities, you should first know the differences.
Like a networking radio?
A first glance should be the cabling: in the beginning times of the office wiring all computers were connected to a single cable harness. Most of these were coaxial cables, such as are used today in the home area as antenna cables for television sets. All computers were connected via the same cable. If one computer then sent data to another, he had to first check whether another computer was sending data over the cable. This method is called CSMA (Carrier Sense Media Access) and follows the principle that devices first check the medium before they start a transmission. If it is determined that the cable is occupied, the computer must wait for a short time and try again. To ensure that the cable is not used too long, all data are divided into small blocks.
Thus, another system has the chance to send a few blocks of its data between two blocks. The result of this technique is clear: the more systems connected by such a cable, the more often this was occupied with the data, and the computers had to wait. Currently, this type of connection is only used in very old office environments.
A structured cabling is provided here: each device is directly connected to a main distributor - a central switch - via its own network cable, a so-called twisted pair cable (short TP). It is also possible to send only one PC on this cable. Because no one else uses this cable, the full speed of the network is always used up to the switch. The server is, of course, connected to this switch. If several PCs simultaneously want to access the server at the same time, the users have to struggle again with the previously described problem because the server system is only connected to the switch with one cable.
However, due to the division into small blocks, the data exchange takes place alternately, as a rule, and with normal utilization, hardly any delay is recognizable for individual PCs in such a configuration. If, however, the capacity of the server connection is fully utilized, because several employees transfer very large video files to the server at the same time, this network is compulsorily slower and sluggish. Those who are often confronted with such problems must make sure that the connection between the server and the switch becomes faster. Then, more data packets can be delivered to the PCs, and the network will be faster overall.
In this problem, it is therefore more counterproductive to expedite the connections of the individual PCs to the switch. This would cause the systems to send more data to the server even faster, and the bottleneck in the server connection is even faster. Today's cable connections work mostly at 100Mbps on the PC side and 1Gbps on the server side.
This speed is perfect for most office environments. If, however, it is primarily about huge amounts of data, such as videos or large-scale images, then such a network can come to its limits. Here, it is recommended to connect the PCs with 1 Gbit / s. However, the server will remain the bottleneck. Meanwhile, however, the 10 Gbit / s technology is also connected to the server. Also in such cases, both server and switch must provide a corresponding port.
A wireless network, a wireless LAN, is always installed where a cable connection is not possible or simply not useful. Thus, wiring is often not possible if no cables can be laid in the walls because, for example, the office owner does not permit any structural changes. The cost factor can also be decisive when it turns out that the cabling of the office or studio becomes very expensive. Finally, the use of a wired network is not useful even if the users primarily use mobile devices such as tablets or smartphones.
In contrast to cabling, the data is now transmitted by radio, for which a wide range of standards are available. These have evolved over the last few years and thus also enable an ever faster data transmission. Until recently, the users had to be satisfied with a transmission rate of 54 Mbps, which is equivalent to half the transmission used in the cable. Thus for a long time the low speed was a weighty argument against the use of pure wireless networks in the office environment.
Most current devices already use the 802.11n standard and can, at least theoretically, achieve a transfer speed of up to 300 Mbit / s, which corresponds to the three-wire cable speed in a standard network with 100 Mbit Br>
WLAN planning: Configuration is critical
The latest devices, which already use the WLAN standard 802.11ac, will theoretically even support values of up to 1.3 Gbit / s at a distance of up to 70 meters. These values are, of course, optimal values, which are rarely or not at all achieved in reality: Similar to the wired network, bottlenecks can occur quickly if several devices simultaneously transmit their data. In addition, with a wireless connection it is absolutely necessary that the entire data traffic has to be decrypted later and later.
This process takes time for each transferred data pact: The users will hardly notice this on their notebooks and laptops, the bottleneck is then the office-installed WLAN receiver, on which all these packets arrive. According to the experience, cheaper devices often have problems with five simultaneous sending devices, while more expensive devices are getting closer to approximately ten devices.
If you now think that with its small network never comes into these areas, should be exactly once again: If the printer should be connected via WLAN and then a notebook and three desktop PCs are added, so it can be for a tablet or Mobile phone, which is then also still in the WLAN, quickly close and thus slowly become. But even with professional, more powerful devices, users can still make mistakes when planning their own WLAN.
The WLAN frequencies are divided into channels, whereby a wireless network always requires a channel for itself. If the neighbor's WLAN is on the same channel, it only works so long until there are too many devices on this channel. Then the WLAN becomes slow and breaks completely at any time. Then you have to switch to another channel. In the hope that the neighbor does not do the same.
In office complexes in which each company operates its own WLAN, the channels are quite fast all occupied. An automatic channel selection, as many WLAN receivers offer, can bring only little relief. Anyone using a current access point or router can set this device to work on the 5 GHz band, which is usually not as crowded.
The third alternative is the electricity network
Conclusion: There is no royal road ...
However, this is changing with the further proliferation of routers that support 802.11n and 802.11ac very fast so that this evasion to the 5 GHz can only serve as a short-term solution. But in the case of a network that is based exclusively on WLAN, users have to contend with another problem: with the so-called illumination. A WLAN connection should be theoretically even up to 100 meters in enclosed spaces. However, in practice there is always some wall in the way, a door is closed, or a metal shelf stands in the way. Such metal shelves or iron grids in the walls are very bad for the function of a wireless network: the metal represents a very excellent shielding against radio waves, and only 10 Mb / s remains of the 300M bit / s.
One way to mitigate these problems is to use a WLAN repeater. However, what you must always be aware of when setting up such a constellation is that the network does not become faster. Therefore, if you want to use your WLAN productively, you must first check the illumination that your WLAN allows in its office environment.
This is best done through the entire office and, for example, using a software on a notebook, measures how good the wireless connection to the WLAN receiver is. For this purpose the various professional programs, but also the freeware Ekahau Heatmapper are available. This results in a clear map, which shows very nicely where the systems are best placed, so that they have the best possible reception in the WLAN.
If it is not possible to route the network cable and, for example, when checking the WLAN, determine that such connections in your environment are not stable or just too slow, the alternative is to revert to the already laid power cables. This type of network connection is often referred to as a Power LAN or dLAN (for direct LAN). There are some manufacturers, who transmit network signals via the power cables in the wall and promise speeds of up to 300 Mbit / s. Similar to the promised speeds in wireless networks, such values are theoretically possible, but most power cables have never been designed to transmit data.
For example, users whose buildings are located in old buildings often have power lines that can not support such speeds. In addition, it is important to remember that the power cabling is very similar to the old coaxial cables: All devices are connected by a cable.
This applies in any case up to the next backup box, where the data transfer usually ends. Whoever decides for this type of network connection will also find that fuses often separate the circuits so that a data transfer from one room to the next is simply not possible. A further disadvantage of this cabling: if the users switch on other electrical devices, they often cause a voltage spike in the power supply.
This then causes the data packets that were traveling at this moment to be destroyed and sent again. This makes the network cards automatically, but basically the entire network is slower and the transfer becomes more unstable. A complete networking over the power line should only be considered by users for their office if there is really no other option available: Often, the access works in an office while it is already a door completely impossible.
Whoever now wonders which is the best solution for his office or studio: There is no general solution for all environments. If you have the option of routing twisted pair network cables, you will usually have a stable network with a transmission rate of 1 Gbit / s available - or even more. If you add a WLAN access point or a corresponding router, you are also equipped for mobile devices, tablets and smartphones.
Always keep in mind that all devices down to the switches and routers should of course support the correspondingly high speed. Although it is certainly no problem, if, for example, printers can be reached with a connection of 100 Mbit / s despite a 1 Gbit network. PowerLAN solutions are excellently suited to be used as a supplement in areas that are not accessible either with wired or wireless connectivity.
No comments:
Post a Comment