Showing papers on "Fast packet switching published in 2003"

Optical switching: switch fabrics, techniques, and architectures

Abstract: The switching speeds of electronics cannot keep up with the transmission capacity offered by optics. All-optical switch fabrics play a central role in the effort to migrate the switching functions to the optical layer. Optical packet switching provides an almost arbitrary fine granularity but faces significant challenges in the processing and buffering of bits at high speeds. Generalized multiprotocol label switching seeks to eliminate the asynchronous transfer mode and synchronous optical network layers, thus implementing Internet protocol over wavelength-division multiplexing. Optical burst switching attempts to minimize the need for processing and buffering by aggregating flows of data packets into bursts. In this paper, we present an extensive overview of the current technologies and techniques concerning optical switching.

IEEE 802.11 packet delay-a finite retry limit analysis

Abstract: The contribution of this paper is on the study of packet delays for the IEEE 802.11 wireless local area network DCF MAC protocol. A method is presented capable of taking into account retransmission delays with or without retry limits. We present an analytical model based on a Markov chain which allows us to derive closed form expressions for the packet delays, the probability of a packet being discarded when it reaches the maximum retransmission limit and the average time to drop such a packet for the basic and RTS/CTS access mechanisms. The results presented are for standard protocol parameters versus the number of contention stations. Finally, the accuracy of the analytical model is verified by simulations.

An introduction to optical burst switching

Abstract: Optical burst switching is a promising solution for all-optical WDM networks. It combines the benefits of optical packet switching and wavelength routing while taking into account the limitations of the current all-optical technology. In OBS, the user data is collected at the edge of the network, sorted based on a destination address, and grouped into variable sized bursts. Prior to transmitting a burst, a control packet is created and immediately sent toward the destination in order to set up a bufferless optical path for its corresponding burst. After an offset delay time, the data burst itself is transmitted without waiting for a positive acknowledgment from the destination node. The OBS framework has been widely studied in the past few years because it achieves high traffic throughput and high resource utilization. However, despite the OBS trademarks such as dynamic connection setup or strong separation between data and control, there are many differences in the published OBS architectures. In this article we summarize in a systematic way the main OBS design parameters and the solutions that have been proposed in the open literature.

Fast flexible filter processor based architecture for a network device

Abstract: A method of filtering data packets in a network device is disclosed. An incoming packet is received from a port and the incoming packet is inspected and packet fields are extracted. The incoming packet is classified based on the extracted packet fields and action instructions are generated. The incoming packet is then modified based on the action instructions. Further, the inspection and extraction includes applying inspection mask windows to any portion of the incoming packet to extract programmable packet fields.

Prevention of deadlocks and livelocks in lossless backpressured packet networks

Abstract: No packets will be dropped inside a packet network, even when congestion builds up, if congested nodes send backpressure feedback to neighboring nodes, informing them of unavailability of buffering capacity-stopping them from forwarding more packets until enough buffer becomes available. While there are potential advantages in backpressured networks that do not allow packet dropping, such networks are susceptible to a condition known as deadlock in which throughput of the network or part of the network goes to zero (i.e., no packets are transmitted). In this paper, we describe a simple, lossless method of preventing deadlocks and livelocks in backpressured packet networks. In contrast with prior approaches, our proposed technique does not introduce any packet losses, does not corrupt packet sequence, and does not require any changes to packet headers. It represents a new networking paradigm in which internal network losses are avoided (thereby simplifying the design of other network protocols) and internal network delays are bounded.

Medium streaming distribution system

Abstract: A relay apparatus for connecting a communication link with a small delay and a communication link with a large delay, includes a first feedback device (71) for receiving a packet of a media stream transmitted on said link with a small delay, and transmitting information including a packet loss rate over a predetermined period to a transmission source (11), adjusting means (13') for adjusting passage of packets received from said network according to transmission capability of said communication link with a large delay, and a second feedback device (73) for transmitting to said transmission source (11) an acknowledge response about a packet transmitted through said adjusting means (13') to said communication link.

Time sliced optical burst switching

Abstract: Time Sliced Optical Burst Switching is a proposed variant of optical burst switching, in which switching is done in the time domain, rather than the wavelength domain. This eliminates the need for wavelength converters, the largest single cost component of systems that switch in the wavelength domain. We examine some of the key design issues for routers that implement time sliced optical packet switching. In particular, we focus on the design of the Optical Time Slot Interchangers (OTSIs) needed to effect the required time domain switching. We introduce a novel nonblocking OTSI design and also show how blocking OTSIs can be used to implement the required switching operations. We study the performance of systems using blocking OTSIs and demonstrate that near ideal statistical multiplexing performance can be achieved using even quite inexpensive, blocking OTSI designs. These results suggest that optical technology may one day be able to provide a cost-effective alternative to electronics in packet switching systems.

Path diversity with forward error correction (PDF) system for packet switched networks

Abstract: Packet loss and end-to-end delay limit delay sensitive applications over the best effort packet switched networks such as the Internet. In our previous work, we have shown that substantial reduction in packet loss can be achieved by sending packets at appropriate sending rates to a receiver from multiple senders, using disjoint paths, and by protecting packets with forward error correction. In this paper, we propose a path diversity with forward error correction (PDF) system for delay sensitive applications over the Internet in which, disjoint paths from a sender to a receiver are created using a collection of relay nodes. We propose a scalable, heuristic scheme for selecting a redundant path between a sender and a receiver, and show that substantial reduction in packet loss can be achieved by dividing packets between the default path and the redundant path. NS simulations are used to verify the effectiveness of PDF system.

Optical signal processing for optical packet switching networks

Abstract: Optical packet switching promises to bring the flexibility and efficiency of the Internet to transparent optical networking with bit rates extending beyond that currently available with electronic router technologies. New optical signal processing techniques have been demonstrated that enable routing at bit rates from 10 Gb/s to beyond 40 Gb/s. We review these signal processing techniques and how all-optical-wavelength converter technology can be used to implement packet switching functions. Specific approaches that utilize-ultra-fast all-optical nonlinear fiber wavelength converters and monolithically integrated optical wavelength converters are discussed and research results presented.

Packet flow processing in a communication system

Abstract: Method and apparatus for processing packet flows in a communication system. In one embodiment, a resource reservation message includes packet flow parameter information used to determine flow treatment of the associated packet flow. The packet flow mapping is based on the quality of service of the associated packet flow. In another embodiment, a bearer connection is established and monitored for information relating to flow treatment.

Packet delay analysis of IEEE 802.11 MAC protocol

Abstract: A new packet delay analysis for the IEEE 802.11b protocol is developed by extending throughput analysis introduced by Bianchi. This analysis is validated by comparison with simulation results using the OPNETTM simulation package. Packet delay results are presented as a function of a number of stations and packet size for basic access and RTS/CTS medium access mechanisms. The proposed analysis identifies when the RTS/CTS mechanism achieves lower packet delay with respect to the basic access mechanism and becomes highly beneficial for the performance of IEEE 802.11 WLANs.

High-performance optical-label switching packet routers and smart edge routers for the next-generation Internet

Abstract: This paper discusses the architecture, protocol, analysis, and experimentation of optical packet switching routers incorporating optical-label switching (OLS) technologies and electronic edge routers with traffic shaping capabilities. The core optical router incorporates all-optical switching with contention resolution in wavelength, time, and space domains. It is also capable of accommodating traffic of any protocol and format, and supports packet, flow, burst, and circuit traffic. The edge router is designed to achieve traffic shaping with consideration for quality of service and priority based class-of-service. Simulation results show packet loss rates below 0.3% at load 0.7 and jitter values below 18 /spl mu/s. The traffic shaping reduces the packet loss rate by a factor of /spl sim/5 while adding negligible additional latency. The OLS core routers and the electronic edge routers are constructed including the field-programmable-gate-arrays incorporating the wavelength-aware forwarding and contention resolution algorithms. The experiment shows optical-label-based packet switching with a packet loss rate near 0.2%.

Frame forwarding in a switch fabric

Abstract: A method of forwarding data in a network switch fabric is disclosed. An incoming data packet is received at a first port of the fabric and a first packet portion, less than a full packet length, is read to determine particular packet information including an opcode value. The opcode value allows the fabric to determine the packet type, such a a whether the packet is a broadcast packet, a unicast packet, a multicast packet, etc. Based on the opcode value read, a particular forwarding table of a plurality forwarding tables is read and an egress port bitmap is determined based on entries read from the particular forwarding table. The incoming data packet is then forwarded based on the egress port bitmap. In addition, the architecture of the switch fabric is also disclosed.

Current issues in packet switch design

Abstract: Addressing the ever growing capacity demand for packet switches, current research focuses on scheduling algorithms or buffer bandwidth reductions. Although these topics remain relevant, our position is that the primary design focus for systems beyond 1 Tb/s must be shifted to aspects resulting from packaging disruptions. Based on trends such as increased link rates and improved CMOS technologies, we derive new design factors for such switch fabrics. For instance, we argue that the packet round-trip transmission time within the fabric has become a major design parameter. Furthermore, we observe that high-speed fabrics have become extremely dependent on serial I/O technology that is both high speed and high density. Finally, we conclude that in developing the architecture, packaging constraints must be put first and not as an afterthought, which also applies to solving the tremendous power consumption challenges.

Versatile optical code-based MPLS for circuit, burst, and packet switchings

Abstract: We will present versatile optical code (OC)-based photonic MPLS, so-called OC-MPLS which ranges from circuit switching, burst switching, to packet switching. OC-label is an identifier attached to the data, of which information is mapped onto an optical code, a sequence of optical pulses. The OC-label recognition is performed by the optical correlation between an incoming OC-label and the OC-label entries. Unique to the OC-label processing is that it is analog operation entirely in optical domain, and no optical logic operation is involved, therefore, the processing speed is only limited by the propagation delay in the optical correlator, which is a passive optical device. This is a key to the ultrahigh-speed processing capability. Circuit switching of OC-label switched path (OC-LSP) is characterized by the finer data granularity than the wavelength path of GMPS, resulting in a better bandwidth efficiency. In a one-way reservation protocol of photonic burst switching, the OC-labeled control packet improves the throughput by nearly cutting the offset time between the control packet and the following data burst. OC-labeled header of the packet can enables the ultrafast routing in photonic packet switching. To exploit the ultrafast routing capability, a new packet switch architecture is investigated, in which the longest-prefix match algorithm as well as WDM buffering into the fiber delay lines are introduced.

Influence of channel BER on IEEE 802.11 DCF

Abstract: A new performance model of the IEEE 802.11 protocol is introduced that calculates throughput, average packet delay, packet drop probability and average packet drop time. This model is validated with simulation results using the OPNETTM simulation package. The proposed model predicts 802.11 protocol performance very accurately since it considers both transmission errors and packet retry limits. The effect of errors and network size on the performance of the basic access scheme, in terms of throughput, packet delay, packet drop time and drop probability is explored.

Enhanced H-VPLS service architecture using control word

Abstract: The present disclosure is generally directed to systems and methods associated with data communications. In a particular embodiment, a method for use of multi-protocol labels switching (MPLS) encapsulation with control word communicated over a distributed computer network is disclosed. The method includes providing MPLS virtual circuit label with the control word associated with a data packet selected from one of a customer data packet and an OAM data packet, and communicating the MPLS packet with control word and the data packet over the distributed computer network. In another embodiment, a method of handling a data packet within a computer network is disclosed. The data packet is either an unknown unicast, multicast, or broadcast packet. The method includes encapsulating the packet into a multi-packet label switching label and a control word, the control word having a source site identity and a multi-cast identity; and distributing the packet to a plurality of sites within the computer network.

A four-terabit packet switch supporting long round-trip times

Abstract: This 4-TBPS packet switch uses a combined input- and crosspoint-queued (CICQ) structure with virtual output queuing at the ingress to achieve the scalability of input-buffered switches, the performance of output-buffered switches, and low latency.

A hybrid optical switching approach

Abstract: Optical circuit switching (OCS) is a sophisticated technology widely deployed in current optical networks, and has many advantages in the transport of stable and long-duration traffic flows. However, it is not suitable for bursty data traffic. On the other hand, an alternative technology, optical burst switching (OBS), well addresses bursty IP traffic transport, but is not suitable for stable and large flows. To transport both types of traffic effectively, a hybrid optical switching approach is proposed which combines OCS and OBS to exploit the merits of both technologies. The performance has been evaluated in terms of throughput and blocking probability.

Services processor having a packet editing unit

Abstract: A services processor includes an editing unit, which performs various functions for editing data packets, such as packet creation, packet encapsulation, and packet replication.

TCP-PR: TCP for persistent packet reordering

Abstract: Most standard implementations of TCP perform poorly when packets are reordered. In this paper, we propose a new version of TCP that maintains high throughput when reordering occurs and yet, when packet reordering does not occur is friendly to other versions of TCP. The proposed TCP variant, or TCP-PR, does not rely on duplicate acknowledgments to detect a packet loss. Instead, timers are maintained to keep track of how long ago a packet was transmitted. In case the corresponding acknowledgment has not yet arrived and the elapsed time since the packet was sent is larger than a given threshold, the packet is assumed lost. Because TCP-PR does not rely on duplicate acknowledgments, packet reordering (including out-of-order acknowledgments) has no effect on TCP-PR performance. Through extensive simulations, we show that TCP-PR performs consistently better than existing mechanisms that try to make TCP more robust to packet reordering. When the case that packets are not reordered, we verify that TCP-PR maintains the same throughput as typical implementations of TCP (specifically, TCP-SACK) and shares network resources fairly.

Timestamping network controller for streaming media applications

Abstract: A system and method of end-to-end clock recovery for media streaming. The method including inspecting a data packet sent by an application to determine a protocol type of the data packet and a location of a timestamp field in the data packet. If the data packet matches a pre-determined protocol type, a new timestamp is generated and inserted into the timestamp field of the packet in real-time in place of an original, possibly less reliable timestamp. The new timestamp accurately defines the time of transmission of the data packet. The data packet is transmitted over a network to a receiver. A receiver receiving the data packet, inspects the received data packet to determine whether the received data packet matches an identification criterion. If the received data packet matches the identification criterion, the receiver generates a local timestamp in real-time and processes the local timestamp and the new timestamp from the received packet to determine an error signal. The error signal is used to adjust the local clock within the receiver.

Packet communication device

Abstract: A reliable packet communication device capable of flexibly adding new functions. A packet communication device is composed of multiple interface elements (IFEs), switching elements (SWE) connecting these IFEs, and a routing manager element (RME) and may also if necessary comprise special functional packet processors (xFPs) capable of different special functions. The interface element and special functional packet processor are connected by a logical bus. For the purpose of connecting the interface elements and special functional packet processors through the switching element when the logical bus has a failure, the logical bus data format is made identical to the data format for passing data through the switch element and a selection circuit is installed in the interface element for selectively sending and receiving data to/from either the logical bus or the switching element.

Method and apparatus for transmission of control data in a packet data communication system

Abstract: A communication system comprising a mobile station and a network implements a persistent packet data control channel that provides for a continuous exchange of control information, such as system information (SI) messages and handoff-related information. The mobile station implements the persistent packet data control channel by mapping the persistent packet data control channel to a packet associated control channel when a packet associated control channel is available and to a virtual associated control channel when a packet associated control channel is not available. The virtual associated control channel allows the mobile station to pass control information to network in the absence of an uplink Temporary Block Flow (TBF).

Ethernet architecture with data packet encapsulation

Abstract: A method of encapsulating data packets for use in a distributed computer network is disclosed. The method includes providing a data packet for transmission over the distributed computer network, the data packet selected from one of a customer data packet and an OAM data packet; and encapsulating the data packet with a medium access control outer packet. The disclosed data packet handling method includes receiving a data packet from a customer facing data port, the customer facing data port within a network node of a computer network; performing medium access control (MAC) learning for the received packet; determining whether the data port is a MAC-in-MAC port; performing a packet mapping to a destination address based on a service provider destination address; and encapsulating the received data packet with a header associated with the service provider.

Switch for local area network

Abstract: Methods and apparatus, including computer program products, implement techniques for processing data packets in a computer network. A packet filter engine (230) is configured to process data packets at wire-speed based on or more user defined packet policies. A received data packet is examined to determine if there is a match between the data packet and one or more packet policies. If no matching packet policies are found, the packet is routed. If a matching packet policy is found, the data packet is processed based on the policy action fields of the matching policy.

System for early packet steering and FIFO-based management with priority buffer support

Abstract: A network interface card (NIC) with FIFO-based packet memory management including priority queues for controlling scheduling of network traffic to thereby prioritize packet transmission for time-critical applications. Furthermore, the invention comprises a system for early packet steering, wherein a packet header is analyzed without having to store the entire packet and before a packet payload arrives, thereby making it possible to make steering decisions before the complete arrival of the packet.

Demonstration of all-optical packet switching routers with optical label swapping and 2R regeneration for scalable optical label switching network applications

Abstract: This paper investigates comprehensive operation and experimentation of an all-optical packet switching router with optical label swapping and reamplification and reshaping (2R) regeneration, capable of multihop operation and Internet protocol (IP)-client interoperability. In particular, the experiment demonstrates successful packet switching and transport up to 11 hops with 10/sup -9/ bit-error rate and error-free up to four hops. Furthermore, this paper demonstrates the optical label switching (OLS) core router and edge routers working together to support IP-client-to-IP-client packet transport and switching across the optical label switching network. The edge router generates an optical label based on the IP header content of the packet and generates an optical label encoded packet, which subsequently ingresses into the OLS network. The optical label switching router (OLSR) forwards the packet with all-optical label swapping at each hop with 2R regeneration. The 2R regeneration leads to an experimentally measured negative penalty and a successful experimental demonstration of multihop cascaded OLSR operation with the edge routers interfacing with IP clients. The successful IP-client-to-IP-client packet forwarding via the edge routers and the cascaded multihop OLSR with all-optical label swapping indicate the viability of OLS in the scalable and transparent IP-over-optical Internet.

40 Gbit/s interface, optical code based photonic packet switch prototype

Abstract: A 40 Gbit/s interface, optical code based photonic packet switch prototype is developed for the first time. Photonic packet switching with 200 Gchip/s all-optical label processing, 40 Gbit/s/port packet switching, and optical buffering to avoid packet collision is experimentally demonstrated.