Network Infrastructure, Wireless Technology
EDUCAUSE Evolving Technologies Committee
Charles Bartel, Carnegie Mellon Unive...

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8:10 a.m. - 9:00 a.m. Thursday...
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Network Infrastructure, Wireless Technology

  1. 1. Network Infrastructure, Wireless Technology EDUCAUSE Evolving Technologies Committee Charles Bartel, Carnegie Mellon University Emilio DiLorenzo, Rochester Institute of Technology November 2003 Introduction Wireless Local Area Networks (WLANs) are being deployed in higher education enterprises all over the world. Institutes are recognizing the value of wireless networks and are using this technology in different ways. Whether to attract students, be more productive and efficient, (anywhere, anytime access), or just because its cool and everyone else is doing it, wireless technology has advanced tremendously in recent years. The media has often portrayed wireless technology as the panacea for the on-going challenge of keeping users connected to the Institutes enterprise network and information resources without hampering productivity. Cultural and social changes are driving more and more people to work “on the go” or from home. These changes require the enterprise IT infrastructure to support remote and mobile users. Approval of the IEEE 802.11 standard for WLANs and rapid progress made toward higher data rates have put the promise of truly mobile computing within reach. While LANs have been a mainstream technology for at least 15 years, WLANs are uncharted territory for most network professionals. There still remain some unanswered questions in this evolution of WLANs technology. In this document we will examine all aspects of WLANs and hopefully in the end you will have a better appreciation of the power of this technology and the tremendous impacts it will have on teaching and learning and how we interact with society in the 21st century. What Is 802.11 Wireless Networking? Before we dive into describing what exactly is 802.11, lets briefly talk about some high level concepts on how WLAN’s operate. WLAN’s use electromagnetic waves to transmit data without physical connection between Access Points (AP) and end users. APs are the components that act as a bridge between the wired network and the WLAN end users. WLANs are a shared media technology, and as such, users will be contending for bandwidth. An example might be a single user downloading a large file or opening up a large e-mail attachment that will definitely impact the overall performance. The range of the APs is directly proportional to speed. As distance between APs and users increases the speed will decrease. Furthermore, we also need to consider the environment around us. For example, building materials, floor plans, and types of other interfering devices can significantly decrease availability and data rates. WLANs transmit data radio waves. Radio waves are transported by Spread-Spectrum Technology (SST). The advantage of this is that that communication is tolerant of some noise and interference. It also allows
  2. 2. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 many users to share a common frequency band, which in turns means, that simultaneous transmission waves can travel on a single frequency. Lastly, wireless adaptors, which are either inserted or already built into laptops, handheld devices and other mobile products, are assigned a Media Access Control (MAC) address that is recognized by the APs. The MAC controls the communications access between the users device and the APs. What Are The Wireless Data Options? Depending on your geographic location you may have a glut of wireless data options, or you may have the opportunity to establish a wireless presence in your community. • 802.11b is the current common denominator in terms of wireless LANs. It operates at 2.4 GHz and operates in the United States as part of the unlicensed ISM band. It provides theoretical data rates of 11Mbps, but in practice data throughput is 5Mbps or lower depending on a number of factors. While there are 11 slices of the spectrum (channels) available for use, because of frequency overlap, there are actually only 3 to 4 channels that can be used across the 11-channel spread. 802.11b can be used for ad hoc networking (peer to peer), enterprise networking (access points deployed to cover a lab, a building or a campus) or to establish point-to-point links for interconnection of networks. • 802.11a is an approved standard that operates in a different radio range (5 GHz) than 802.11b and offers higher theoretical and actual data speeds than 802.11b (54Mbps theoretical, roughly 25Mbps actual). It operates under three bands of spectrum and can provide up to 12 non- interfering channels (although there is still a need to provide some channel separation in the design of an 802.11a wireless LAN). It is widely viewed as one successor to the very pervasive 802.11b. • 802.11g is an approved standard that uses the same radio spectrum as 802.11b, but operates at speeds similar to 802.11a. One of the pros is that because it uses the same radio spectrum, it is possible that devices using 11g will be able to “fall-back” to using 11b in the presence of an 11b only wireless LAN. A con is that 11 g is still restricted to the same 3 to 4 channels for design, and it may be difficult to design a high bandwidth 11g network without a significant amount of overlapping (interfering) adjacent channels. A further complication is that in the current implementation of the specification, 11g clients slow down to 11b client speeds (11Mbps or less) if an 11g network supports both 11b and 11g clients. • Bluetooth is more geared as a PAN (Personal Area Network) than as a LAN. It is a “standard” in the sense of a large number of technology companies have come together to develop the specification for devices that will use Bluetooth to inter-communicate with each other. Bluetooth uses the same unlicensed radio spectrum as 802.11b (and g) and as such there is a potential that the presence of Bluetooth and 11b devices in the same area will interfere with each other. There is an IEEE standard (802.15) that is based on the Bluetooth specification and there are efforts within the IEEE 802 working groups to have 11b(g) and 15 devices interoperate in the same radio space. While these efforts may someday bear fruit, the current devices now flooding the market will not necessarily provide a comfortable level of cohabitation of the radio spectrum. • Cellular and “3G” services- these are wireless data services being offered or talked about by primarily the various cellular providers (Verizon, Sprint, AT&T). For the most part, the notion is to carry data over the same radio spectrum as a cellular call, but to use different schemes to increase the data throughput. For example, Verizon is offering Express Network with a max throughput of 144Kbps and an average speed of 40-60Kbps. While this speed is perhaps double or triple previous schemes and rivals typical dial-up modem speeds, it is slow compared to wireless LAN PAGE 2 OF 9
  3. 3. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 speeds. There are even higher bandwidth services being planned by many of these same cellular providers. • Others (Infrared, laser, microwave)- There are wireless options ranging from low-speed (infrared) to very high speed (155Mbps and beyond) lasers that also fall under the wireless data umbrella. These products are more typically used for establishing point-to-point links. There are some emerging products (Canopy from Motorola for example) that can provide point to multipoint service at 10Mbps (and beyond) speeds of relatively long distances. There is a new wireless wide area standard being developed (IEEE 802.16) that will allow high speed point to point or point to multi- point connections. This technology is being viewed as a wireless replacement or enhancement for MANs (Metropolitan Area Networks) like DSL or Cable Modem. There are also some excellent web sites that provide a plethora of information: 1. - Institute of Electrical and Electronics Engineers 2. - Federal Communications Commission 3. - Wi – Fi Alliance 4. - European Telecommunications Standards Institute Why Is Wireless Networking Important To Higher Education? In a nutshell wireless networking is important because it is convenient. Students are increasingly mobile in their communication styles and activities, and to extend a campus network without wires allows for new cultures of learning too form. Once the network is everywhere, learning will be untethered about the campus. Wireless networking also gives universities a cost effective way to extend the campus network to previously unwirable locations, or quickly provide a network in a space that has none. Higher education Institutions are not immune by today’s economic challenges. IT budgets are being cut as much as 25% or more, not to mention that capital expenditures are non existent or being put off indefinitely. WLAN’s give Institutions a means of progressing their IT infrastructure to support the mission of teaching and learning in a fairly inexpensive way. What Are The Implementation Challenges? Perhaps security is the biggest challenge and one that has received the most publicity. WLAN’s specifications are based on the assumption that all who access the WLAN’s are trusted users. The WLAN specifications need to include security in order to make it an enterprise service. Malicious intruders can penetrate several kinds of attacks in a WLAN (Sniffing, Spoofing, Jamming, Denial of Service attacks). Anyone of these attacks could turn out to be a major catastrophe for Institutions, both on teaching and learning and bad publicity. The fact that there is “no wire” to be tapped leads us to two primary security issues. The first is that all transmissions may be monitored by anyone in reception range, these are the attacks listed above. The second is that of access. Assume that one would like to grant access to the network to only certain individuals. The challenge is how to accomplish this for a user that is not physically attached to a switched point on the network, but rather on a shared bus that is roaming around campus. The second challenge, but less limited is roaming. Roaming issues are present in some 802.11 wireless networks. In a cellular network, as one moves between ‘cells’, a handoff takes place, and calls survive the transition between cellular towers and networks. However, since the IEEE did not initially specify a standard for the handoff protocol, vendors developed their own methods for dealing with this issue. The end result is that roaming is a problem for some of today’s wireless networks, due to vendor interoperability issues. Even PAGE 3 OF 9
  4. 4. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 with a homogeneous deployment of equipment from one manufacturer, roaming will only work when there is a single IP subnet for a given wireless network. This is primarily due to the fact that all IP connections depend on a given host keeping the same address for the duration of a connection. If a wireless client roams, and obtains a new IP address in the process, connections will be dropped. Seamless roaming dictates a large, flat layer-2 network, and issues with the scalability of large flat networks are well known (this is one of the reasons we have the word “router” in our telecom dictionaries). Broadcast storms are one of the primary concerns, as a large flat network grows, which in turn means significant down time to users. Another challenge is the behavior of radio signals on you campus and the potential interferers of those signals. Wireless LANs use radio as the communications medium and in fact use unlicensed radio spectrum that they cohabitate with many devices. Some devices like 2.4GHz cordless phones can cause major problems with Wi-Fi devices in the area. Bluetooth devices are becoming more pervasive and these too can interfere with 802.11b and g Wi-Fi networks. Also in this area, the reflection or absorption of radio signals by the materials used in the construction of a building can cause problems or anomalies in coverage. As a rule of thumb, if a material absorbs sound waves for acoustic insulation of a space, it will likely absorb radio waves as well. The above can translate into the need for additional access points to cover a given space and ultimately this translates into higher costs for deployment. Lastly we cannot forget the cultural and social issues that could present themselves as challenges. While the network is generally viewed as a tool in the educational community, it can also be a distraction to some students. The technological problem presented by this is how to allow faculty in a given classroom control over what students may do on the wireless network. Immediately we think about students cheating, making social plans after class, or just not paying attention because there to busy surfing the net. Who Are The Major Vendors? • In terms of wireless LANS, the IEEE is the major standards body with the FCC governing the radio spectrum in the United States. Local regulatory agencies worldwide govern the radio spectrum (and its usage) in different ways. • Depending on which version of wireless data you are considering the major players may be different. • Cellular providers are likely to be your “3G” providers (Verizon, Sprint, AT&T,). • Most wired network companies now offer 802.11b wireless solutions as part of their product line (Cisco, Nortel, 3Com, Enterasys and Extreme to name a few). There are a few companies that are almost exclusively fixed on wireless data solutions. Proxim is a company that offers a full spectrum of wireless data solutions. Also, there are a number emerging “switched” wireless vendors that are for the most part exclusively wireless LAN vendors, Airespace, Airflow, Aruba Networks, Chantry Networks, Symbol Technologies and Trapeze Networks to name a few. What Are The Rules of Thumb For Judging Among Them? This is a question that many vendors can debate about for hours on end, my wireless is better that your wireless scenarios. I like to keep things very simple and stick to facts, not marketing or media hype. After PAGE 4 OF 9
  5. 5. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 all if an implementation fails or service is bad who do you think the Administration will point the finger at? I can safely say that it wont be the vendor. Here are some key points to consider in the WLANs marketplace: • Longevity of the vendor (are they going to survive this economy and do they have the vision and strategy to get there?) • Throughput and scalability of the vendor’s solution. Typically enterprise level vendors have these issues well under control. • Up-gradability. Since this is a fast developing technology can the vendor upgrade their hardware with new software to provide new features? • Support of external antennas • Transmit power levels • Ease of configuration and management • Interoperability in a non-homogenous environment (especially in a higher education environment) How Should We Proceed? Proceeding with a deployment of WLAN’s based on the 802.11b specification will not be a mistake. It is important that Institutions understand and answer a few hard questions: • What am I trying to achieve with WLAN’s? • What is the value proposition for doing this? • Is my infrastructure ready to accept WLAN’s? • Can I support this new service? • Can I accept the inherent risks of today’s WLAN’s? Of course there are many more questions to answer, the important point to make is that the WLANs market is constantly evolving. As the industry matures, we will see more and more implementations of WLAN’s in the enterprise. When Will Wireless Become Essential On Campuses Today. Your peer institutions are using it as a selling point for students to try and gain some competitive edge that distinguishes them from other Institutions. Student expectations are high, especially on technological campuses. However, essential is not the same thing as ubiquitous. It will take time for us to determine if this technology is going to be required everywhere on campus. How Is The Industry Evolving? With current trends clearly indicating a growing acceptance and adoption of WLAN/s in the enterprise and coupled with the fact that the industry is trying hard to provide multiple options and ratify specifications, WLAN’s is evolving at warp speed. In fact, many leading experts and colleagues are not referring to WLAN’s but as “Mobile Computing”. The reason is simple, your cell phone, your PDA, your car that you drive and many other devices can and are being considered wireless in nature. So referring to wireless as networks is already becoming a dinosaur and true Mobile Computing is taking over. So, let’s take a quick look at how the industry is really evolving from a technical, management and security standpoint: There are emerging approaches to try to increase the available bandwidth within Wi-Fi networks. PAGE 5 OF 9
  6. 6. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 These have been nick-named “Switched” wireless to distinguish from the current standards-based shared- radio 802.11wireless networks. Standards-Based Wi-Fi networks use “intelligent/smart/heavy” Access Points (APs) wired to wireless bridge/router/gateway to connect wireless users to campus wired networks. “Switched” wireless LANs use “dumb/lite” APs (essentially a radio and NIC) connected to a central device. The central device acts as the controller of the “dumb” APs. There are a number of non-standards bases approached to provide a “switched” solution. Some vendors use tunable antennas and/or variable RF power levels to adjust the coverage pattern of the AP. Some have coverage-prediction capabilities to assist in WLAN design and implementation. Some vendors have built-in the management functionality of “middle-boxes” (ReefEdge, Vernier, BlueSocket) into their control devices Players in the space include: Airespace, Airflow, Aruba Networks, Chantry Networks, Cisco, Extreme Networks, Foundry Networks, Legra Systems, Nortel Networks, Proxim, Symbol Technologies and Trapeze Networks to name a few. Some caveats to consider if you are looking at these products: While they all support IEEE 802.11standards-based (Wi-Fi) clients, most vendors use proprietary approaches for RF management. Presently there is no standard for this area of WLANs (no interoperability between vendor products) Most vendors only support 802.11b (11Mbps) clients (not 11g or 11a 54Mbps clients). As mentioned earlier, the IEEE standards are moving to address some of the issues with respect to bandwidth. 802.11a and 802.11g are both targeting higher bandwidths (54Mbps/sec speeds). The IEEE is also starting to address the concept of Quality of Service (QOS) for WLANs. Without a major breakthrough speeds are not likely to go much higher than 54Mbps/sec. Therefore, IEEE and vendors alike will need to address and deliver QOS issues needed for advancing reliable amounts of bandwidth to applications that will require it (i.e. 802.11b, VOIP phones). The IEEE is also working on extending their standards to implement multi-vendor roaming interoperability. Finally most importantly efforts are being made towards advanced security standards that are causing IT professional’s sleepless nights. What Are The Issues To Be Addressed? When talking to anyone in the IT field, rest assured that if they say everything is working fine and there are no issues, they are lying. In a nutshell I see three key issues with WLAN’s that need to be addressed. Security, security, security. As mentioned throughout this document security is one of the main considerations when contemplating WLAN’s. Much effort is underway to offer advanced security, however were not there yet. There are tactical solutions that users can put in place. One of those solutions is using Virtual Private Network (VPN) to force users to authenticate and most importantly create an encrypted tunnel from the AP to the user. The issue around VPN is that depending on the vendor you implement for VPN you may end up needing to install client software, which will cause management and licensing issues. A second tactical solution might be to use your vendors proprietary security if you are installing a single vendor solution, including using the vendors wireless adaptors. For example, if you have installed a full Cisco wireless infrastructure, you have the option of using Cisco’s own security methods incorporated into their products. However, you can only take advantage of this feature if you are using Cisco’s wireless adaptors. Any other vendor’s adaptors will not be able to take advantage of Cisco’s security. There are a number of efforts in the area of security and a number of ways to secure a Wi-Fi network. There is an alphabet soup of options (WEP, TKIP, EAP, LEAP, PEAP, IEEE 802.11i, IEEE 802.1x, PAGE 6 OF 9
  7. 7. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 VPNs…). Given the limited scope of this whitepaper, we will refer the reader to an excellent whitepaper that Dell has written on the subject: A user of a WLAN should not experience roaming issues due to the fact that they changed location. Obviously this completely defeats the purpose of being mobile. All APs allow for roaming within the same subnet. In a perfect world, products should be able to roam multiple subnets with an enterprise WLAN. As with security some vendors have their own proprietary methods for handling roaming issues. Finally Quality of Service versus more bandwidth. This pervasive debate will be brought down to the wireless level, where QOS will likely win due to the fact that higher speeds will create distance limitations that can’t be overcome by “replacing the cabling”. The Wi–Fi Alliance has a subcommittee working on and exploring an adaptable industry standard. Where Are The Likely Impacts In The Coming One To Three Years? In the near term, demand for WLANs will continue to grow and be implemented in additional areas that were once not thought of. Bandwidth usage will lead to redesigns of existing WLANs. These redesigns may have a negative impact on an enterprises ability to support seamless roaming. As time goes on, additional features and/or functionality may require upgrades of the underlying AP hardware supporting your WLAN. In short, expect to allocate more resources to supporting your WLAN as it grows. As with all technologies, as the usage pushes the limit of the technology unforeseen problems will arise. Conclusion With the alphabet soup of wireless standards and protocols and the appearance that wireless LANs are still an immature technology given the state of flux within the standards and vendor implementations, one could assume that it is still best to sit back and wait for the dust to settle. Unfortunately, given the apparent commoditization and “consumerization” of wireless gear campus IT professional are facing the situation that wireless LANs will show up on their campuses. They now have the choice of deploying them in as structured way as possible as a central service, or watch wireless LANs spring up like weeds in an unstructured and insecure way. PAGE 7 OF 9
  8. 8. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 Related Higher Education Projects • Wireless Andrew- Carnegie Mellon University • Mobile Computing- Rochester Institute of Technology • Kiewit Wireless- Dartmouth College • DragonFly-Drexel University • Nomad- University of Tennessee –Knoxville • Wireless LAN Pilot - Virginia Tech • University of Minnesota Duluth Related EDUCAUSE2003 Sessions • Seminar 08F - Implementing a Campus-Wide Wireless LAN: Considerations and Practices PLEASE NOTE: Separate registration and fee is required to attend this seminar. 8:30 a.m. - 4:30 p.m. Tuesday Network Infrastructure and Equipment, Wireless Local Area Network (WLAN) Class on the Go: Want Fries with That? 11:40 a.m. - 12:30 p.m. Wednesday Distributed Learning, Handheld Computers, Portals, Wireless Technology Large-Scale Deployment of a Secure Wireless Network 3:50 p.m. - 4:40 p.m. Wednesday Network Security and Applications, Wireless Local Area Network (WLAN) No More "Online": Wireless to the Distance Learner 4:55 p.m. - 6:10 p.m. Wednesday Distance Education, Wireless Local Area Network (WLAN), Wireless Technology Wireless Local Area Networking 4:55 p.m. - 6:10 p.m. Wednesday Network Infrastructure and Equipment, Wireless Local Area Network (WLAN) Cutting the Cord: Wireless Networking Made Hard PAGE 8 OF 9
  9. 9. EDUCAUSE EVOLVING TECHNOLOGIES COMMITTEE, OVERVIEW OF WIRELESS TECHNOLOGY, 10/21/2003 8:10 a.m. - 9:00 a.m. Thursday Network Infrastructure and Equipment, Wireless Local Area Network (WLAN), Wireless Technology Network Management 4:55 p.m. - 6:10 p.m. Thursday Network Management, Network Security and Applications, Wireless Technology Wireless Campus Networking 4:55 p.m. - 6:10 p.m. Thursday Network Infrastructure and Equipment, Wireless Local Area Network (WLAN) PAGE 9 OF 9