The Dynamic Port Reservation Protocol

TitleThe Dynamic Port Reservation Protocol
Publication TypeThesis
Year of Publication2001
AuthorsReitz, A.
AdvisorKravets, R.
Academic DepartmentComputer Science
UniversityUniversity of Illinois at Urbana Champaign
AbstractIn the current Internet, Network Address Translation (NAT) gateways that provide port address translation are quite popular. These gateways allow many hosts to be multiplexed on one single IP address and still maintain full outbound connectivity. However, the ability to share a single IP address with many hosts doesn't come for free - the NAT denies these hosts the ability to receive unsolicited inbound connections. The lack of inbound connectivity is fine for a user base that wishes to only surf the web and check e-mail. However, with the rise of peer-to-peer applications such as instant messaging, Napster and Internet-enabled games, users are demanding inbound connectivity at an ever-increasing rate. Most NAT gateways already provide a method to restore limited inbound connectivity. It is possible to instruct the NAT gateway to forward unsolicited inbound packets on a specific port to a specific internal host. This is typically hard to configure and is only available to the administrators of the NAT gateway. In order to make the port-forwarding solution generally usable, a new network protocol is needed. The Dynamic Port Reservation Protocol (DPRP) allows endusers to establish their own port-forwarding rules on the NAT gateway. These port forwarding rules are not static { rather, they are dynamic. End users are only able to get a lease on a port, which they may use for a limited period of time, before it is reclaimed by the NAT gateway. In this manner, the gateway administrator is able to keep some measure of control over the port-forwarding rules and users are able to run their peer-to-peer applications with full functionality.
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