Routing table

About: Routing table is a research topic. Over the lifetime, 16589 publications have been published within this topic receiving 336842 citations. The topic is also known as: routing information base & RIB.

Greedy Virtual Coordinates for Geographic Routing

Abstract: We present a new approach for generating virtual coordinates that produces usable coordinates quickly and improves the routing performance of existing geographic routing algorithms Starting from a set of initial coordinates derived from a set of elected perimeter nodes, greedy embedding spring coordinates (GSpring) detects possible dead ends and uses a modified spring relaxation algorithm to incrementally adjust virtual coordinates to increase the convexity of voids in the virtual routing topology This reduces the probability that packets will end up in dead ends during greedy forwarding The coordinates derived by GSpring achieve routing stretch that is up to 50% lower than that for NoGeo, the best existing algorithm for deriving virtual Euclidean coordinates for geographic routing For realistic network topologies with obstacles, GSpring coordinates achieves from between 10 to 15% better routing stretch than actual physical coordinates

DUNE-a multilayer gridless routing system

Abstract: Advances of very large scale integration technologies present two challenges for routing problems: (1) the higher integration of transistors due to shrinking of featuring size and (2) the requirement for off-grid routing due to the variable-width variable-spacing design rules imposed by optimization techniques. In this paper, we present a multilayer gridless detailed routing system for deep submicrometer physical designs. Our detailed routing system uses a hybrid approach consisting of two parts: (1) an efficient variable-width variable-spacing detailed routing engine and (2) a wire-planning algorithm providing high-level guidance as well as ripup and reroute capabilities. Our gridless routing engine is based on an efficient point-to-point gridless routing algorithm using an implicit representation of a nonuniform grid graph. We proved that such a graph guarantees a gridless connection of the minimum cost in multilayer variable-width and variable-spacing routing problem. A novel data structure using a two-level slit tree plus interval tree in combination of cache structure is developed to support efficient queries into the connection graph. Our experiments show that this data structure is very efficient in memory usage while very fast in answering maze expansion related queries. Our detailed routing system also features a coarse grid-based wire-planning algorithm that uses exact gridless design rules (variable-width and variable-spacing) to accurately estimate the routing resources and distribute nets into routing regions. The wire-planning method also enables efficient ripup and reroute in gridless routing. Unlike previous approaches for gridless routing that explore alternatives of blocked nets by gradually tightening the design rules, our planning-based approach can take the exact gridless rules and resolve the congestion and blockage at a higher level. Our experimental results show that using the wire-planning algorithm in our detailed routing system can improve the routability and also speed up the runtime by 3 to 17 times.

Failure inferencing based fast rerouting for handling transient link and node failures

Abstract: With the emergence of voice over IP and other real-time business applications, there is a growing demand for an IP network with high service availability. Unfortunately, in today's Internet, transient failures occur frequently due to faulty interfaces, router crashes, etc., and current IP networks lack the resiliency needed to provide high availability. To enhance availability, we proposed failure inferencing based fast rerouting (FIFR) approach that exploits the existence of a forwarding table per line-card, for lookup efficiency in current routers, to provide fast rerouting similar to MPLS, while adhering to the destination-based forwarding paradigm. In our previous work, we have shown that the FIFR approach can deal with single link failures. In this paper, we extend the FIFR approach to ensure loop-free packet delivery in case of single router failures also, thus mitigating the impact of many scenarios of failures. We demonstrate that the proposed approach not only provides high service availability but also incurs minimal routing overhead.

Managing processing utilization in a network node

Abstract: A technique for managing the utilization of processing resources involves filtering packets that are sent to a CPU for learning before allowing the packets to reach the CPU. The filtering involves determining if related packets have already been allowed to reach the CPU for learning and using the knowledge about related packets to determine if a current packet should be allowed to reach the CPU In one embodiment, the processing resource of the CPU are conserved by allowing one packet per flow to reach the CPU for learning The one packet is used by the CPU (102) to generate the necessary forwarding information and to initiate programming of the hardware-based forwarding table (112) so that subsequent packets of the same flow can be forwarded directly from the hardware-based forwarding engine (104).

Method for load balancing in routers of a network using overflow paths

Abstract: A method for managing packet flow in network routers is provided which communicates the congestion status among the ports inside routers in the network, and substantially eliminates packet dropping due to congestion by providing overflow paths for destination IP addresses. Each router in a network stores at least two possible output paths for selected destination IP addresses, so that the router may direct the output of packets appropriately when congestion is detected on one of the paths. A forwarding table stores the possible output paths for each destination IP address.