ACM SIGACT News
Rate vs. buffer size: greedy information gathering on the line
Proceedings of the nineteenth annual ACM symposium on Parallel algorithms and architectures
A tight bound on online buffer management for two-port shared-memory switches
Proceedings of the nineteenth annual ACM symposium on Parallel algorithms and architectures
Packet mode and QoS algorithms for buffered crossbar switches with FIFO queuing
Proceedings of the twenty-seventh ACM symposium on Principles of distributed computing
Best Effort and Priority Queuing Policies for Buffered Crossbar Switches
SIROCCO '08 Proceedings of the 15th international colloquium on Structural Information and Communication Complexity
Improved Competitive Performance Bounds for CIOQ Switches
ESA '08 Proceedings of the 16th annual European symposium on Algorithms
Competitive buffer management for shared-memory switches
ACM Transactions on Algorithms (TALG)
A Tight Bound on Online Buffer Management for Two-Port Shared-Memory Switches
IEICE - Transactions on Information and Systems
Proceedings of the twenty-first annual symposium on Parallelism in algorithms and architectures
A survey of buffer management policies for packet switches
ACM SIGACT News
Rate vs. buffer size--greedy information gathering on the line
ACM Transactions on Algorithms (TALG)
Online scheduling of packets with agreeable deadlines
ACM Transactions on Algorithms (TALG)
Providing performance guarantees in multipass network processors
IEEE/ACM Transactions on Networking (TON)
FIFO queueing policies for packets with heterogeneous processing
MedAlg'12 Proceedings of the First Mediterranean conference on Design and Analysis of Algorithms
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We study a basic buffer management problem that arises in network switches. Consider $m$ input ports, each of which is equipped with a buffer (queue) of limited capacity. Data packets arrive online and can be stored in the buffers if space permits; otherwise packet loss occurs. In each time step the switch can transmit one packet from one of the buffers to the output port. The goal is to maximize the number of transmitted packets. Simple arguments show that any work-conserving algorithm, which serves any nonempty buffer, is 2-competitive. Azar and Richter recently presented a randomized online algorithm and gave lower bounds for deterministic and randomized strategies. In practice, greedy algorithms are very important because they are fast, use little extra memory, and reduce packet loss by always serving a longest queue. In this paper we first settle the competitive performance of the entire family of greedy strategies. We prove that greedy algorithms are not better than 2-competitive no matter how ties are broken. Our lower bound proof uses a new recursive construction for building adversarial buffer configurations that may be of independent interest. We also give improved lower bounds for deterministic and randomized online algorithms.In this paper we present the first deterministic online algorithm that is better than 2-competitive. We develop a modified greedy algorithm, called semigreedy, and prove that it achieves a competitive ratio of $17/9 \approx 1.89$. The new algorithm is simple, fast, and uses little extra memory. Only when the risk of packet loss is low does it not serve the longest queue. Additionally we study scenarios when an online algorithm is granted additional resources. We consider resource augmentation with respect to memory and speed; i.e., an online algorithm may be given larger buffers or higher transmission rates. We analyze greedy and other online strategies.