11.26.06
Geographic Addressing in WANs to Simplify Routing and Enable New Services
Mobility is becoming a huge driving force on the Internet today. More and more mobile users connect to the Internet everyday through the use of laptops, PDA’s and smart phones. Applications that take advantage of this shift towards mobility are gaining popularity. It is also becoming apparent that having host location information available in the network can unlock a whole other class of applications. Already, applications exist that could benefit from the addition of location information to the network. Geographic location in WAN addressing would reach this goal of location information in the network to enable new services. In addition, geographic addressing has the added benefit of simplifying routing.
Current Applications
There are already many applications used by mobile and stationary users that could benefit from location information provided at the network layer. Location-based search engines are becoming popular means of finding places and business in a specific geographic region. Google Maps [2] is one example; users can enter the kind of business they are looking for and the geographic region in which they would like to find it. However, mobile users may not always know their exact location but would like to search for places near them. Geographic addresses would allow Google Maps to infer a host’s location directly from the host’s address.
Another existing application that would benefit from universal location information is the face-to-face social networking application from Jambo Networks [1]. Jambo utilizes an ad-hoc Wi-Fi connection on a mobile device to locate nearby users of interest. This allows Jambo users with similar interest to meet up face-to-face when they are near each other. Although Jambo is able to identify when users are nearby, it only know that they are close. It is unaware of its own geographic location and the location of others. Adding location information to this sort of application could enable the system to map exactly where another user is and perhaps even suggest a nearby meeting place for the users.
These are just two example of where adding geographic information to the network would improve the quality and functionality of existing applications. Certainly there are many other applications that would benefit in similar ways. Imagine a calendar program that modifies notification times depending on how far the user is from the location of an appointment or an IM client that sorts buddies by proximity. Yet, the real benefit from adding location information to WAN addresses is the new applications and services that it would enabled.
Potential Services and Applications
Automobiles are one of the next big applications for mobile networks and Internet access. Soon, vehicles will be connected to the Internet allowing real-time access to multimedia, entertainment, the web, and email. Many vehicles are also being equipped with GPS-based navigation systems. Combining these two technologies would generate a plethora of new services.
Traffic management is an area that would benefit from location-based networking in automobiles. For public safety reasons, such a system could be used to broadcast emergency messages to vehicles. Ambulances and fire trucks would be able to broadcast to exactly the vehicles along their route in order to alert drivers to their presence, a more effective supplement to horns and sirens used today. In other cases, location information provided may help locate distressed users. Geographic addressed networking would also allow vehicles to participate in traffic condition monitoring and reporting. Instead of embedding costly sensors and monitors into roadways, the vehicles themselves could be utilized to collect and relay traffic conditions.
Vehicular location-based networking will also enhance the navigation systems currently used. Today’s systems can locate points of interest based on a set of stored data that may only be update yearly. With Internet access and location information, navigation systems could become much more interactive, finding up-to-date places and events that are both interesting and close to a user.
Outside of the vehicle, location information will also lead to numerous services for mobile hosts. Obviously, navigation and local search systems similar to those in vehicles could be implemented on mobile devices. To pay for these free services such as search engines, many service providers rely on advertisement. Location information will allow advertisers to better target their advertisement and maximize their return. The power that location adds to the Internet and web is almost unlimited. Imagine a restaurant guide that searches not only by the kind of cuisine but also by the proximity to the user. The ability to leverage location-based services without needing to know exactly location will become invaluable especially as more and more user go mobile and venture to unfamiliar places.
A final example of potential new uses for geographic addressing in the WAN is IPTV. Broadcast television technology is gradually going to make the leap to IP-based transition. There is no doubt of this as more and more technologies are converging on IP. It is just a matter of time. Current broadcast technologies are very much localized. Over-the-air broadcast and cable television are tied to a user’s physical location. With the move to IP, this tie important to location is lost. This link is necessary to provide targeted programming to specific geographic areas. For example, newscasts are typically localized as well as sporting events. In fact, all major professional sporting events have rules dictating which geographic regions can view events on television. Adopting geographic addressing would regain this link and allow for such rules and localizations to continue. Interestingly enough, this scheme works for wired hosts as well as mobile.
Simplified Routing
A final argument for geographic addressing is a simplification of routing. There are several proposals for performing geographic routing such as GFG [3], GPSR [4], and RFC 2009 [5]. One of the reoccurring reasons for exploring geographic routing is for simplicity and easy of routing.
Geographic routing requires much less state information than hierarchically routing. Routing decisions are based on the relative location of the destination and router rather than a best match on possible IP prefixes. In this way, many routing approaches are able to incorporate some sort of greedy routing for at least a portion of the routing, a much faster approach than having to perform a lookup.
Another routing benefit to geographic addressing is easy server selection. Although physical proximity is not the best indicator of RTT and thus routing distance, it has been argued to be reasonably good in practice [6]. The server selection process can be greatly simplified by choosing the service replica that is nearest a host as determined from location information in a host’s address. Many systems most infer a host’s location through the use of probing. Geographic addressing could eliminate the need for this extra overhead.
Overcoming Obstacles
Geographic addressing in the network is a substantial change to the current Internet Protocol. It will take a lot of work in order to convince others that it a worth while change. Opponents to geographic address might argue that all that it does is bloat the IP layer. It is seen as an unnecessary addition that just adds complex to an already complex protocol. Services that need location information could just obtain it from higher layer mechanisms.
However, with network level geographic addressing, all hosts can enjoy the benefits of location-based addressing. Host that do not have a means of acquiring location information themselves (no GPS receiver) can obtain it from their access point. In cellular networks for example, hosts without GPS can use the coordinates of their base station as their location or even triangulate their location from multiple base stations. Without location in the network layer, there is no guarantee that a host will be able to obtain location information.
One shortcoming of geographic addressing is inter-domain routing. So far, the major geographic routing proposals have focused on routing within individual networks, wireless networks in particular. It is not immediately apparent how geographic routing could be translated to work with multiple domains. A clear example of the problem is if two users are sitting next to each, but connected to different network, say one wireless and one wired. A greedy approach of trying to route nearest the other host will simply not work. Some sort of hybrid approach will need to be used in order to first route to the other domain and then route geographically to the specific host.
Despite the few challenges described above and the challenge of deploying such a drastic change in the Internet, geographic addressing would unleash a whole new set of services and features. Applications today stand to be improved by the adoption of location-based addressing as well as countless yet to be imagined applications that will take advantage of geographic addressing. In addition, we may even see a simplification of routing on the Internet.
Sources
1. “Jambo Networks” http://www.jambo.net
2. “Google Maps” http://maps.google.com
3. P. Bose, P. Morin, I. Stojmenovic, and J. Urrutia. Routing with guaranteed delivery in ad hoc wireless networks. In Proc. ACM DIALMWorkshop, pages 48–55, Seattle,WA, USA, Aug. 1999. ACM.
4. B. Karp and H. T. Kung. GPSR: Greedy perimeter stateless routing for wireless networks. In Proc. ACM/IEEE MobiCom, pages 243–254, Boston, Mass., USA, Aug. 2000. ACM.
5. T. Imielinski, J. Navas. “RFC 2009 GPS-Based Addressing and Routing.” IETF, Network Working Group. Nov 1996.
6. M. J. Freedman, K. Lakshminarayanan, and D. Mazieres. OASIS: Anycast for any service. In NSDI, 2006.