Extricom Wireless LAN - Frequently Asked Questions
General Product Questions
Coverage, Capacity, and Bandwidth
Mobility
Simplicity and Scalability
Security
What are the advantages of the Extricom WLAN System?
Do you support the IEEE 802.11 standards?
Can the Extricom system operate alongside my existing WLAN equipment?
Can I use any Wi-Fi client on the Extricom WLAN?
Can your system support demanding real-time applications such as voice, video conferencing, and CRM?
What do you mean by "multi-layer WLAN"?
Can the Extricom system be used in any country?
What are the advantages of the Extricom WLAN System?
The Extricom WLAN System was conceived for a new era in wireless adoption and value: one in which organizations expect to make Wi-Fi pervasive in their operation, enabling all users, applications, and devices to benefit from wireless. In contrast to the traditional "cell-based" WLANs of today, the Extricom solution provides for superior and guaranteed performance, maximum flexibility in tailoring wireless to the enterprise, all-the-while dramatically reducing the complexity of design, deployment, and maintenance.
Do you support the IEEE 802.11 standards?
Yes. Extricom designs and builds only standards-compliant solutions.
Can the Extricom system operate alongside my existing WLAN equipment?
Yes. Since the Extricom system is compliant with the IEEE 802.11 "Wi-Fi" standard, and can therefore be integrated into your environment without changes to your current systems.
Can I use any Wi-Fi client on the Extricom WLAN?
Yes. The Extricom WLAN is completely client agnostic, which means any off-the-shelf Wi-Fi client will function on the Extricom system, without any modifications or special software agents.
Can your system support demanding real-time applications such as voice, video conferencing, and CRM?
Yes. Extricom's solution is designed specifically with high-bandwidth and real-time applications in mind. It delivers maximal and steady connection rates everywhere, even when mobile, while enabling the physical bandwidth of specific channels to be allocated for specific enterprise applications.
What is a "channel blanket"?
Channel blanket is the term Extricom uses to refer to the way the Extricom system maximizes the use of every available Wi-Fi channel. The channel blanket topology is the answer to all of the inherent scale, performance, and complexity limitations imposed by the cell-based WLAN approach. The Extricom solution allows each 802.11a/b/g radio channel to be used everywhere, on every access point (AP), to create overlapping and contiguous zones of coverage (channel blankets). Among the advantages of the channel blanket is the elimination of RF cell planning, co-channel interference, AP-to-AP handoffs, unpredictable bandwidth, and quality of service (QoS) degradation due to the contention between voice and data or mixed mode.
What do you mean by "multi-layer WLAN"?
By using multi-radio, 802.11a/b/g APs, the Extricom system enables the deployment of multiple, overlapping and concurrent channel blankets, using any combination of channels, in any band, in any mode. The net effect is like having the functionality of multiple WLANs in one physical implementation, with the ability to specifically allocate each WLAN layer to different types of users, or devices, or applications, or any combination of each.
Can the Extricom system be used in any country?
Yes, the Extricom solution can be deployed in any country that allows the use of the Wi-Fi specification.
How does the Extricom system resolve the traditional trade-off between coverage and capacity?
What is the difference between data rate and throughput?
You guarantee both data rate and throughput. How?
How does the Extricom WLAN System eliminate co-channel interference?
In terms of capacity and bandwidth, how is the channel blanket superior to cell-planning?
Channel limitations will become even more severe with 802.11n. How will Extricom overcome these?
How does the Extricom system resolve the traditional trade-off between coverage and capacity?
Cell-based WLAN design is a difficult balancing act between having too many APs - and thus too much co-channel interference and degraded capacity - or too few APs - and thus not enough coverage. In contrast, the Extricom system maximizes both capacity and coverage, by permitting dense deployments of APs, without co-channel interference, thereby guaranteeing complete coverage with the highest data rate and throughput everywhere.
What is the difference between data rate and throughput?
The data rate is the raw speed at which the Wi-Fi communications are made between client and the infrastructure. The specification defines the maximum data rate for 802.11b and 802.11g to be 54 Mbps, while 802.11b has a maximum data rate of 11 Mbps. Throughput is the net speed of communications when all of the protocol's overhead is removed. The maximum theoretical throughput for a 54 Mbps channel is approximately 25 Mbps, and this decreases rapidly as the distance between the client and the AP increases.
You guarantee both data rate and throughput. How?
Unlike cell-based WLANs, the Extricom channel blanket guarantees that the desired data rate and maximal system throughput is always delivered. While cell-based systems may attempt to raise the data rate by adding more APs, the corresponding increased co-channel interference, will degrade the actual over-the-air throughput to well below maximal. And this is even before additional throughput-degrading effects, such as those from edge users and mixed mode devices, are factored in.
How does the Extricom WLAN System eliminate co-channel interference?
The Extricom WLAN Switch fully controls the transmissions of every AP connected to it. The switch is therefore able to avoid co-channel interference by permitting multiple APs to simultaneously transmit on the same channel only if the switch determines that they won't interfere with each other.
In terms of capacity and bandwidth, how is the channel blanket superior to cell-planning?
A common misconception in cell-based WLANs is the belief that just adding more APs and re-using the same channels will increase capacity. In practice, however, the very mechanisms of 802.11 (e.g. the Clear Channel Assessment (CCA) algorithm, rate adaptation) prevent channel re-use from providing appreciable increase in capacity, let alone bandwidth (throughput). In contrast, the channel blanket eliminates co-channel interference, the inaccuracies of CCA, and edge users stemming from rate adaptation, to ensure that the maximum throughput is delivered throughout the system, a function only of the density of APs. Simply put, in an Extricom system the more APs you add, the higher the system throughput.
What is TrueReuse?
TrueReuse is the name of the algorithm that enables multiple APs to transmit on the same channel, at the same time, yet without co-channel interference. The TrueReuse intelligence is essentially enabling the purest form of channel re-use, dynamically and in real-time, thereby providing the real capacity benefits of frequency reuse that cell-based WLANs have only promised.
Channel limitations will become even more severe with 802.11n. How will Extricom overcome these?
To reach their promised data rate and throughput, 802.11n systems will need to "bond" two existing Wi-Fi channels into one. So, if cell-planning was difficult with three channels, how much harder (or impossible) will it be with two? Since Extricom does not depend on cell-planning, opting instead for the channel blanket topology that makes each available channel present at every AP, Extricom customers will readily see the benefits of increased capacity and bandwidth promised by 802.11n.
What's the distinction between portability and mobility?
In terms of mobility, how is the Extricom system superior to a cell-based WLAN?
Can I be fully mobile with a voice handset that has WPA security?
What's the distinction between portability and mobility?
Portability is the ability to establish a wireless connection when the client is located at point A or point B. Historically, Wi-Fi networks have been optimized for wireless data connectivity, which is not delay sensitive and does not require a continuous connection as the client travels from point A to point B. New applications such as voice, locationing, connectioned data applications, and streaming video, however, demand mobility - that is, a continuous and steady connection as the client moves from point A to point B.
In terms of mobility, how is the Extricom system superior to a cell-based WLAN?
The Extricom system eliminates AP-to-AP handoffs, thereby delivering superior performance for all clients that require seamless mobility without the delays and latency of AP handoffs.
Can I be fully mobile with a voice handset that has WPA security?
Yes. The elimination of AP-to-AP handoffs ensures that all applications, including voice, will be fully and seamless mobile, no matter what type of security they are able to support.
Transmitter Power Control can degrade performance for voice users. Does the Extricom system depend on this?
Voice users, whether handsets or Vocera badges, require a steady, consistent signal in order to perform best. Transmitter power control (TPC), a mechanism often used by cell-based WLANs to counter the effects of co-channel interference and other issues, is detrimental to such voice users. The Extricom WLAN achieves its superior performance without resorting to TPC.
Why is the Extricom system the only one that can support UMA cellular/Wi-Fi convergence in the enterprise?
Once again, Extricom's advantage is the result of the absence of AP-to-AP handoffs. UMA (Unlicensed Mobile Access) systems enable a GSM cellular phone to seamlessly roam onto a Wi-Fi network and vice-versa. When the UMA phone is on a Wi-Fi network, however, it establishes a secure, encrypted tunnel to the UMA server. In any system where an AP handoff is experienced, this tunnel is severed every time the client attempts such a handoff, forcing the phone to look for the GSM network again. This is not the case for Extricom.
How is design and deployment of an Extricom WLAN different?
Can I place APs anywhere I want?
Do I need to conduct an RF site survey?
How is the Extricom system self-adapting to changes in the physical environment?
What is the process for adding APs?
Can I manage the Extricom system centrally?
Is there any limit to scalablity?
How is design and deployment of an Extricom WLAN different?
Thanks to its unique Interference-Free™ architecture. Extricom's WLAN eliminates much of the deployment complexity that characterizes the cell-based WLAN alternative. In the Extricom system, there is no need for RF cell planning, chasing co-channel interference, or having to iteratively design and re-design in an attempt to find an acceptable balance of coverage, capacity, and mobility.
Can I place APs anywhere I want?
Yes. The Extricom WLAN switch enables the placement of APs at any density and even varying densities as the physical environment dictates, without worrying about co-channel interference, channelization, and excessive/insufficient overlap between APs.
Do I need to conduct an RF site survey?
The time-consuming and iterative RF site surveys traditionally needed in cell-based WLANs are not necessary. Thanks to Extricom's great flexibility in AP placement, an Extricom system can be fully deployed without concern for cell-planning or RF constraints, thereby reducing the site survey to just physical equipment installation planning.
How is the Extricom system self-adapting to changes in the physical environment?
The Extricom WLAN system is resilient to changes in the surrounding environment thanks to the uplink path diversity effect created by its APs. The system always selects the optimal AP to serve the client, dynamically adjusting for variations in the physical space. In addition, Extricom does not resort to Transmitter Power Control (TPC) to do this, thereby avoiding its detrimental effects on real-time applications such as voice over WLAN.
What is the process for adding APs?
Whenever changes to the physical environment occur (e.g. room reconfigurations, additional walls, space expansion), the Extricom system can be modified simply by adding and/or moving APs. This is literally a plug-and-play process that does not require any re-design or even changes to the configuration in the WLAN switch.
Can I manage the Extricom system centrally?
Yes. The Extricom system includes a web-based management capability. This enables the user to manage all switches, and corresponding APs, centrally. In addition, SNMP-based control is available for those organizations that wish to use their existing management console infrastructure.
Is there any limit to scalablity?
There is no limit to the physical scale of an Extricom WLAN deployment. Each WLAN forms its own high-performance Wi-Fi zone, and the performance of any individual WLAN switch is independent of the any other individual switch. The system can be continually expanded without any performance degradation simply by adding more WLAN switches, enabling the enterprise to cover any size service area.
Can a wireless system be as secure as a wired one?
Does the Extricom solution support standards-based security?
Does the Extricom system support LEAP?
In an Extricom WLAN, will security impact performance?
How does Extricom solve the trade-off between mobility and security?
Does the Extricom WLAN support LDAP and active directory for role-based access controls?
Does the Extricom system support multiple SSIDs and VLANs?
Is rogue AP detection included in the Extricom WLAN?
Can a wireless system be as secure as a wired one?
Yes. In fact, today a wide range of technologies and options is available for the organization, which means the crucial differentiator is not the availability of technology, but rather the deployment and successful operation of the appropriately selected technologies. The Extricom WLAN permits any security technology to be used in a fully mobile environment.
Does the Extricom solution support standards-based security?
Yes, the Extricom system is 802.11i compliant.
Does the Extricom system support LEAP?
Yes. Extricom builds standards-compliant systems, but it recognizes the importance of supporting Cisco's LEAP authentication which, although proprietary, is widely deployed. By offering such legacy support, Extricom offers a smooth transition to stronger and standards-based authentication mechanisms.
In an Extricom WLAN, will security impact performance?
No. In the Extricom system, security functions are performed in a separate, dedicated hardware co-processor in the WLAN switch. This ensures that no matter how rigorous the security, including AES encryption, communications performance is not affected.
How does Extricom solve the trade-off between mobility and security?
In an Extricom WLAN, a client device experiences no AP-to-AP handoff while inside the channel blanket. As a result, any type of security session, even WPA, will be maintained continuously as the client moves.
Does the Extricom WLAN support LDAP and Active Directory for role-based access controls?
Yes. The Extricom solution supports the 802.1X authentication framework as part of its compliance with the 802.11i standard. Consequently, the Extricom system is transparent to these upper-level authentication methods and thereby enables them to be deployed.
Does the Extricom system support multiple SSIDs and VLANs?
Yes. Each channel blanket supports up to 16 unique SSIDs which can also be mapped to their own VLANs.
Is rogue AP detection included in the Extricom WLAN?
Yes. Extricom offers built-in rogue AP detection, at no extra charge. In fact, since one of the radios inside each AP can be dedicated to security monitoring, the organization gains all the performance and accuracy benefits of dedicated monitoring, without the added cost of a security sensor overlay array.