Yakov Rekhter

Tag-switching architecture: overview

Tag switching is based on two key ideas: (1) single forwarding algorithm based on label (tag) swapping, and (2) support for a wide range of forwarding granularities that could be associated with a single tag. Combination of these two ideas facilitates the development of a routing system that is functionally rich, scalable, suitable for high forwarding performance, and is capable of graceful evolution to address new and emerging requirements in a timely fashion.

Scalable inter-domain routing architecture

As internets grow, both in size and in the diversity of routing requirements, providing inter-domain routing that can accommodate both of these factors becomes increasingly crucial. We propose a scalable inter-domain routing architecture consisting of two major components: source-demand routing (SDR) and node routing (NR). The NR component pre-computes and installs routes that are shared by a significant number of sources. These generic routes are commonly used and warrant wide propagation. The SDR component provides on-demand computation and installation of specialized routes that are not shared by enough sources to justify computation by NR. The potentially large number of different specialized routes, combined with their sparse utilization, make them too costly to support with the NR mechanism. Together NR and SDR address the issue of scaling to global internet sizes without restricting the availability of a diverse set of routes. Routing will adapt naturally over time to changing traffic patterns and new services by shifting computation and installation of particular types of routes between the two components. To complement earlier discussions of SDR design choices [3], this paper evaluates the algorithmic design choices for the NR component in terms of scalability and functionality. In addition, we discuss mechanisms for improving the scaling properties of link-state SDR, and for integrating the two components of the architecture.

Tag switching architecture overview

Tag switching is a way to combine the label-swapping forwarding paradigm with network-layer routing with particular application to the Internet. This has several advantages. Tags can have a wide spectrum of forwarding granularities, so at one end of the spectrum a tag could be associated with a group of destinations, while at the other end, a tag could be associated with a single application flow. At the same time, forwarding based on tag switching, due to its simplicity, is well suited to high-performance forwarding. These factors facilitate the development of a routing system that is both functionally rich and scalable. Last, tag switching simplifies the integration of routers and asynchronous transfer mode switches by employing common addressing, routing, and management procedures.

An architecture and implementation toward multiprotocol mobility

The challenge is to design a set of protocols that provide seamless and robust network connectivity to mobile users for a variety of existing network protocol suites. An important additional constraint is that the design should not require any changes to the existing stationary infrastructure and it should interoperate with the existing protocol stacks at the stationary hosts. We propose a mobile data link (MDL) architecture that endeavors to meet this design challenge. The architecture hides the topological effects of mobility at the data link layer, thus making topology changes due to mobility transparent at layers above the data link. This provides a single mechanism to support a variety of distributed applications that use different protocol stacks without requiring changes to the implementations of the stacks. Further, the-solution provides the enhanced degree of mobility provided by prior network layer solutions. The novel features of the proposed solution are the use of the network layer infrastructure for carrying data link traffic, the ability to dynamically maintain a data link overlay over a common network layer infrastructure, and efficient handling of the broadcast traffic. We have developed an MDL architecture that allows data link networks (formed by the interconnection of LAN segments by bridges) to be dynamic, thereby supporting mobile hosts, eliminating the need for manual configuration. Moreover, our scheme efficiently handles broadcasts and multicasts. >

Injecting inter-autonomous system routes into intra-autonomous system routing: a performance analysis

The current TCP/IP Internet may be modeled as an arbitrary interconnection of autonomous systems 1 ( [Honig 90]) . Routing in the Interne t is partitioned into intra-autonomous system routing (intra.-S routing) an d inter-autonomous system routing (inter-AS routing) . If both a source and a destination belong to the same AS . then routing between the source and th e destination is completely realized by employing intra-AS routing procedure s used by the AS . However . if a source and a destination belong to differen t ASs . then routing between the source and the destination cannot be realized either completely within the inter-AS routing or completely within th e intra-AS routing . but involves both the intra and inter-AS routing . That . i n turn, requires a certain degree of interaction between the intra and inter-A S routing procedures .

IDRP protocol analysis: storage complexity

IDRP is an inter-domain routing protocol that is based on the path-vector routing algorithm. This paper analysis storage complexity of the protocol and suggests possible local techniques for reducing it.

Constructing intra-AS path segments for an inter-AS path

Based on the connectivity of an autonomous system to other autonomous systems we can classif y all autonomous systems as either stubs or non-stubs . A stub autonomous system may be connecte d to only one another autonomous system . Non-stub autonomous system may be connected to several other autonomous systems. A non-stub autonomous systems may be further classified as either multihomed or transit based on their willingness to carry transit traffic. A multihomed autonomous system is a non-stub that does not carry traffic that neither originates nor terminate s at that autonomous system . A transit autonomous system is a non-stub that is willing to carr y (under certain policy restrictions) traffic that neither originates nor terminates at that autonomou s system .

Forwarding database overhead for inter-domain routing

The network layer of the current Internet is built around the packet switched architecture. As the Internet grows both in size and diversity of services, providing mechanisms to contain the growth of information that is necessary to correctly perform packet switching becomes one of the crucial issues in the overall Internet architecture. The dominate factor of this issue is the routing data stored in Forwarding Information Bases. This paper analyzes storage overhead associated with the inter-domain component of Forwarding Information Bases and evaluates possible techniques for containing the growth of this overhead.