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No Wires No Worries: Extricom

2/18/2008
The Wi-Fi wireless networks have gained access into the offices, households, and even into the outdoor installations on the telecommunication poles and building rooftops. Since the beginning of wireless era, we have nevertheless continued meeting various limitations and barriers, which do limit the mobility and differentiate the wireless technology from the wire and optical concepts, and that specifically within the concept of real-time applications.
In 1999 the 11th workgroup of the Standardization Commission presented the IEEE 802 Standard for wireless communication. Still the same year the IEEE 802.11 Standard was accompanied by the additional 802.11b Standard, which extended the original one by the supports of 5.5 and 11.0 Mbps speeds. The following years the additional extensions of the standard came in, which brought higher transfer speed, further modulations or frequency bands, improvements of authentication and ciphering, harmonization standard, and many other standards or their concepts like for instance the self-organizing MESH networks. These standards are being promoted to the hardware manufacturers thanks to the Wi-Fi alliance, which certifies the respective products. The Wi-Fi wireless networks have penetrated into offices, households, and even into the outdoor installations on the telecommunication poles and building rooftops. Since the beginning of wireless era, we have nevertheless continued meeting various limitations and barriers, which do limit the mobility and differentiate the wireless technology from the wire and optical concepts, and that specifically within the concept of real-time applications.

Now we will concentrate on that original idea of 802.11b/g/a indoor networks operated primarily within the offices and on the company premises and we will look into the bowels of the wireless system of the new generation – the Israeli-English concept of Extricom.

It has been a commonplace for many years now to move around the company with your PDA, Wi-Fi telephone, notebook or for example barcode reader and not to be literally tied up with the Ethernet cable. But what do we encounter during various installations? The limited reach of the wireless signal and limited utilization of the wireless network within the edges of signal coverage, limited number of the user devices under single access point and the resulting limited transfer capacity, and finally yet importantly, the annoying interference. If you are planning on building an extensive wireless network that would at least solve some of these deficiencies, you will most likely encounter other problems. As an example, we will mention the Wireless Distribution System, a system that provides connections of the access points by wireless means into a single network. The concept of the hybrid WDS network will on one hand save us the used-up channels of the frequency band, but on the other hand, it will take away the significant portion of our transmission capacity as the "payment" for the communication of each access point, and in addition to that, we will be limited only to the use of static ciphering keys. Should we require full transmission capacity, we will not use the WDS but we will choose our own channel of the frequency band at each access point. At this point the "planning" becomes really important because we start playing a battle of interference among the neighboring and our own access points. Our battlefield has a limited number of channels and the usage of neighboring channels is impossible due to the overlaps. And the actual mobility factor of the user device poses another problem. At the moment the user goes out of reach of one device to the reach of the other, the disassociation of the access point inevitably happens together with the repeated association with the new access point. This in the case of WDS means the new MAC address of the access point for the wireless client, and with no WDS, it also means the new channel, and in addition, for the real-time applications like VoIP or VPN it means the higher latency or even the loss of connection. The problems of mobility can be experienced significantly during stronger ciphering; therefore, during the usage of WPA: TKIP, or during the usage of WPA2: CCMP. Once we try to extend the network or solve some problem through the change in configuration, it becomes inevitable to reconfigure several standalone devices and that is from the standpoint of administration very inconvenient, particularly if the network had been built using various models or brands.

The following table will give us a rough idea of the benefits and disadvantages of various concepts. All applications had been built on the devices with a single wireless interface. In the case of WDS or MESH networks, the multi-radio access points will be take care of the transfer capacity problem because we will separate the backbone and the access point to another physical medium but we will simultaneously worsen the situation of channels utilization and increase the management demands.

Application
Utilization of Channels
No. of AP MAC addresses
Transfer Capacity*
Maximum of Users*
Coverage Radius*
Management
1x AP
1
1
54Mb/s
16
20 m
1x
4x AP
4
4
aggr. 4x 54Mb/s
4x 16
4 x 20 m
4x + channel planning
4x AP WDS
1
4
¼ 54Mb/s
4
4 x 20 m
4x AP + WDS
4 x AP in 1 blanket
1
1
aggr. 4x 54Mb/s
4x 16
4 x 20 m
1x centrally
* the table shows illustrative values

During our imagination of the wireless installation, which would guarantee us mobility, capacity, throughput and service availability, we are going to need something which we would call the "channel blanket". All access points work within the unified channel, whereat they are managed and administered centrally. Expansion of such system means only physical installation and no additional channel planning and device configuration.

Such concept, as mentioned earlier, is being brought by Extricom. The individual access points are the units centrally managed by the wireless switch that connects to these access points by the means of a metal cable and the corresponding communication among them is ciphered. During the communication, the so-called "Packet-by-Packet" control is executed, which is the patented system assessing the signal of the clients' devices and managing the communication exactly from the best-accessible access point, etc. This all happens in real time and in practice it means that the user is once associated with the network and then the user can move freely among the individual access points without the loss of connection and with zero latency, and that even when strong ciphering is used. Extricom offers simultaneously several types of the access points, which differ in the number of wireless interfaces – the single-radio, dual-radio, and quadruple-radio ones. Each interface can be configured to the same frequency band (up to 3 times) or to the different frequency band – 802.11b, 802.11b/g, 802.11g, and 802.11. Also the mode called "Rouge AP Detection" can be incorporated. The Rouge AP represents the weakly or not at all secured access points, which had appeared within your network and the detection system would report them as potential threat to your network. Another patented technology is the so-called "TrueReuse", which enables dynamic optimization of the frequency in order to bring full capacity to all users within each access point. We can guarantee high throughput for the required network applications, and thanks to several layered blankets, we can physically separate various types of operations for each wireless interface, also logically up to 16 SSID (including the 802.1Q support). Even with existence of many patented technologies, the Extricom solution works within the aforementioned 802.11 Standards; therefore, no additional clients' devices would be necessary.

The project solution of Extricom breaks all barriers of the today's wireless networks and it guarantees us to have no worries while being connected utilizing no wires. Throughput, accessibility, mobility, security and scalability are the main advantages of Extricom. If you were caught by this new technology, please check more product information here.

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