Wireless LAN Services for the NDSU Campus - DRAFT
In the last year, faculty, staff and students on the NDSU campus have begun purchasing and deploying access points demonstrating demand for this type of network service. ITS and CITPG are responding to this demand by organizing an open forum in which members of the NDSU community may come and ask questions and tell us what applications they have for WLANs. Based on the information gathered in the open forum, ITS will prepare a set of requirements for deploying a WLAN service. In addition, an implementation and operational plan will be created. Costs associated with this service will be included in these plans and the campus will be asked to evaluate the cost verses benefit of the service and recommend whether the service should be deployed and how funding should be made available. This document is intended to provide a very brief overview of what a WLAN is and what some of the technical and other issues associated with WLANs are in the hope that it will facilitate discussion during the open forum.
A wireless local area network (WLAN) is a data communication system implemented as an extension to, or as an alternative for, a wired LAN within a building or campus. Using electromagnetic waves, WLANs transmit and receive data over the air, minimizing the need for wired connections. Typically, WLANs are comprised of devices known as access points which send and receive signals to mobile devices using special wireless network cards. The range of the signals to and from the access point will vary depending on the transmitter strength and the type of antenna used. Thus, WLANs combine data connectivity with user mobility, and, through simplified configuration, enable movable LANs. The IEEE standard for WLANs is 802.11x where `x' is currently either `a' or `b'. Most current installations are based on the 802.11b standard which supports data speeds of up to 11 Mbs. The newer 802.11a standard supports data speeds of up to 54 Mbs.
Support
New technologies like WLANs require new or expanded support services. Devices which will be used with a WLAN will need wireless networking cards. Users will need to be trained to properly configure their wireless cards and/or a standardized setup developed that works within the NDSU WLAN. Networking staff will need to be trained to diagnose and fix problems unique to wireless networks. Help Desks will need to train their staff to answer common questions and develop documentation for support personnel and users alike. Content (e.g. web material) may need to be modified to support new kinds of devices (e.g. PDAs, tablet PC's, etc.) which were not viable without wireless networks.
Security
Security has not been a design requirement in many of the IT services in use on the NDSU campus today because when they were designed it was not nearly the issue it is today. This needs to be addressed but, in the mean time, we absolutely do not want to deploy new services without considering security along with the other requirements. WLANs present unique challenges in the security area. Because there is no physical connection required, by default, it is not possible to control who may connect to the network. In addition, while WLANs support encrypted communications, it turns out that the standard encryption method is weak which means that it is possible to “eaves-drop” on wireless communications. There are solutions to these problems but they may, in turn, require new services to be established which will add to the support issues addressed above. The security questions have a direct impact on the functionality of the WLAN.
Functionality
WLANs, like other services, should be designed to meet a particular need or needs. At this point, it appears that the need is mobility and convenience and not a new teaching, research, or administrative IT paradigm. This would imply that WLANs would be in areas such as the student union and library. The population in these areas of the campus is highly transitory; members of the campus are coming and going all the time. In addition, they are also frequently used by the general public. This raises questions about who should have access and how that will be facilitated. If access will be restricted then a mechanism to control access will be required.
WLANs are shared networks meaning that the bandwidth they provide is shared among all of the devices which connect to an access point. The 802.11b standard supports speeds up to 11 Mbs which, even when shared, is sufficient for web browsing, email, etc. However, for multi-media applications, file services, and other bandwidth intensive applications, the shared and relatively low speed nature of a WLAN can lead to poor performance. The 802.11a standard, which supports speeds up to 54Mbs, addresses some of these limitations. The right type of equipment for NDSU will depend on the applications it is intended to support. In some cases, no matter which standard is used, wired networks will be the only viable networking option.
There are two general classes of access points, ones that are intended for home use and others that are intended for business use. The home models often are multi-purpose devices that include standard wired connections, a router/firewall, and DHCP server. Without getting into the technical details, if these devices are not configured properly they will interfere with non-wireless devices elseswhere on the network. We have seen several instances of this already which is what drew our attention to the interest in WLAN technology. As the definition above notes, WLANs are really extensions of the wired LAN and need to be carefully planned for including insuring they don't negatively impact other users. In addition, many of the wired components are manageable remotely which improves the efficiency of the networking staff by allowing them to monitor and configure devices without having to physically connect to the devices. Business/professional versions of access points support the same functionality and should be used in a WLAN for NDSU.
Wireless networks are an exciting technology that provides convenience and flexibility. As we have seen, like any technology, WLANs have limitations that require careful planning. In addition, depending on the functionality required, WLANs may require changes or additions to the existing wired network infrastructure. By considering all of the options, the NDSU campus will make the best decision for the future.