Universal Bufferless Packet Switching

Abstract

Abstract. A packet-switching algorithm specifies the actions of the nodes in order to deliver packets in the network. A packet-switching algorithm is universal if it applies to any network topology and for any batch communication problem on the network. A long standing open problem has concerned the existence of a universal packet-switching algorithm with near optimal performance guarantees for the class of bufferless networks where the buffer size for packets in transit is zero. We give a positive answer to this question. In particular, we give a universal bufferless algorithm which is within a poly-logarithmic factor from optimal for arbitrary batch problems:where T is the packet delivery time of our algorithm, T * is the optimal delivery time, n is the size of the network, and N is the number of packets. At the heart of our result is a new deterministic technique for constructing a universal bufferless algorithm by emulating a store-and-forward algorithm on a transformation of the network. The main idea is to replace packet buffering in the transformed network with packet circulation in regions of the original network. The cost of the emulation on the packet delivery time is proportional to the buffer sizes used by the store-and-forward algorithm. We obtain the advertised result by using a store-and-forward algorithm with logarithmic sized buffers. The resulting bufferless algorithm is constructive and it can be implemented in a distributed way.

Bounding Residence Times for Atomic Dynamic Routings

“…The greedy scheduling studied in [24,5] and in this paper is essentially a non-algorithmic rule, which does not require algorithmic coordinations among packets (agents). This stands in sharp contrast to other related work on packet routing, where centralized or distributed algorithms are needed to produce global or distributed arrangements for storing and forwarding packets collaboratively [1,20,21,25,27]. Leighton et al [21,20] prove that there exists a polynomial-time computable schedule under which the residence time of every packet is O(l + b), where l is the length of the longest given path and b the largest number of packets that traverse a single edge during the entire course of the routing.…”

A Multifunctional Integrated Circuit Router for Body Area Network Wearable Systems

“…2) Routing by Circuit Switching: One of the methods that can overcome the drawbacks of packet switching is circuit switching at the MAC layer, because it is a bufferless method. In bufferless networks, such as optical networks or some Network-on-Chip (NoC) architectures, a packet arrives at the destination node over intermediate nodes without any buffering [2], [16], [25], [38]. This approach usually reduces the total network power consumption and delay under low network workloads, but routing performance for randomly generated packets is significantly worse when compared to packet switching for high network workloads.…”