bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing for scale and differentiation
Authors: Sollins Karen R.
Published: October 2004

Naïve pictures of the Internet frequently portray a small collection of hosts or LAN's connected by a "cloud" of connectivity. The truth is more complex. The IP-level structure of the Internet is composed from a large number of constituent networks, each of which differs in some or all of transmission technologies, routing protocols, administrative models, security policies, QoS capabilities, pricing mechanisms, and similar attributes. On top of this, a whole new structure of application-layer overlays and content distribution networks, equally diverse in the sorts of ways mentioned above, is rapidly evolving. Virtually any horizontal slice through the current Internet structure reveals a loosely coupled federation of separately defined, operated, and managed entities, interconnected to varying degrees, and often differing drastically in internal requirements and implementation. Intuitively, it is natural to think of each of these entities as existing in a region of the network, with each region having coherent internal technology and policies, and each region managing its interactions with other regions of the net according to some defined set of rules and policies.In this paper, we propose that a key design element in an architecture for extremely large scale, wide distribution and heterogeneous networks is a grouping and partitioning mechanism we call the
region
. Furthermore we postulate that such a mechanism can provide increased functionality and management of existing unresolved problems in current networks. The paper both describes a proposed definition of the
region
concept and explores the utility of such a mechanism through a series of examples. We claim that there is significant added benefit to generalizing the idea of the
region
.
BANANAS
Authors: Kaur H. Tahilramani , Kalyanaraman S. , Weiss A. , Kanwar S. , Gandhi A.
Published: October 2004

Today the Internet offers a single path between end-systems even though it intrinsically has a large multiplicity of paths. This paper proposes an evolutionary architectural framework "BANANAS" aimed at simplifying the introduction of multipath routing in the Internet. The framework starts with the observation that a path can be encoded as a short hash ("PathID") of a sequence of globally known identifiers. The PathID therefore has global significance (unlike MPLS or ATM labels). This property allows multipath capable nodes to
autonomously
compute PathIDs in a partially upgraded network without requiring an explicit signaling protocol for path setup. We show that this framework allows the introduction of sophisticated explicit routing and multipath capabilities within the context of widely deployed connectionless routing protocols (e.g. OSPF, IS-IS, BGP) or overlay networks. We establish these characteristics through the development of PathID encoding and route-computation schemes. The BANANAS framework also allows considerable flexibility in terms of architectural function placement and complexity management. To illustrate this feature, we develop an efficient variable-length hashing scheme that moves control-plane complexity and state over-heads to network edges, allowing a very simple interior node design. All the schemes have been evaluated using both sizable SSFNet simulations and Linux/Zebra implementation evaluated on Utah's Emulab testbed facility.
Towards a logic for wide-area Internet routing
Authors: Feamster Nick , Balakrishnan Hari
Published: October 2004

Interdomain routing is a massive distributed computing task that propagates topological information for global reachability. Today's interdomain routing protocol, BGP4, is exceedingly complex because the wide variety of goals that it must meet---including fast convergence, failure resilience, scalability, policy expression, and global reachability---are accomplished by mechanisms that have complicated interactions and unintended side effects. The complexity of wide-area routing configuration and protocol dynamics requires mechanisms for expressing wide-area routing that adhere to a set of logical rules. We propose a set of rules, called the
routing logic
, which can be used to determine whether a routing protocol satisfies various properties. We demonstrate how this logic can aid in analyzing the behavior of BGP4 under various configurations. We also speculate on how the logic can be used to analyze existing configuration in real-world networks, synthesize network-wide router configuration from a high-level policy language, and assist protocol designers in reasoning about new routing protocols.
NIRA
Authors: Yang Xiaowei
Published: October 2004

This paper presents the design of a new Internet routing architecture (NIRA). In today's Internet, users can pick their own ISPs, but once the packets have entered the network, the users have no control over the overall routes their packets take. NIRA aims at providing end users the ability to choose the sequence of Internet service providers a packet traverses. User choice fosters competition, which imposes an economic discipline on the market, and fosters innovation and the introduction of new services.This paper explores various technical problems that would have to be solved to give users the ability to choose: how a user discovers routes and whether the dynamic conditions of the routes satisfy his requirements, how to efficiently represent routes, and how to properly compensate providers if a user chooses to use them. In particular, NIRA utilizes a hierarchical provider-rooted addressing scheme so that a common type of domain-level route can be efficiently represented by a pair of addresses. In NIRA, each user keeps track of the topology information on domains that provide transit service for him. A source retrieves the topology information of the destination on demand and combines this information with his own to discover end-to-end routes. This route discovery process ensures that each user does not need to know the complete topology of the Internet.
FARA
Authors: Clark David , Braden Robert , Falk Aaron , Pingali Venkata
Published: October 2004

sloppy This paper describes FARA, a new organization of, network architecture concepts. FARA (Forwarding directive, Association, and Rendezvous Architecture) defines an abstract model with considerable generality and flexibility, based upon the decoupling of end-system names from network addresses. The paper explores the implications of FARA and the range of architecture instantiations that may be derived from FARA
. As an illustration, the paper outlines a particular derived architecture, M-FARA, which features support for generalized mobility and multiple realms of network addressing.
The case for TCP/IP puzzles
Authors: Feng Wu-chang
Published: October 2004

Since the Morris worm was unleashed in 1988, distributed denial-of-service (DDoS) attacks via worms and viruses have continued to periodically disrupt the Internet. Client puzzles have been proposed as one mechanism for protecting protocols against denial of service attacks. In this paper, we argue that such puzzles
must
be placed within the slim waistline of the TCP/IP protocol stack in order to truly provide protection. We then describe several scenarios in which TCP/IP puzzles could be used to thwart port scans and coordinated DDoS attacks. Finally, while puzzles hold the promise of being able to change the Internet landscape, we describe a large number of open research issues that must be resolved before such a vision can be achieved.
An end-to-end approach to globally scalable programmable networking
Authors: Beck Micah , Moore Terry , Plank James S.
Published: October 2004

The three fundamental resources underlying Information Technology are bandwidth, storage, and computation. The goal of wide area infrastructure is to provision these resources to enable applications within a community. The end-to-end principles provide a scalable approach to the architecture of the shared services on which these applications depend. As a prime example, IP and the Internet resulted from the application of these principles to bandwidth resources. A similar application to storage resources produced the Internet Backplane Protocol and Logistical Networking, which implements a scalable approach to wide area network storage. In this paper, we discuss the use of this paradigm for the design of a scalable service for wide area computation, or programmable networking. While it has usually been assumed that providing computational services in the network will violate the end-to-end principles, we show that this assumption does not hold. We illustrate the point by describing Logistical Network Computing, an extension to Logistical Networking that supports limited computation at intermediate nodes.
A hash-based strong-password authentication scheme without using smart cards
Authors: Ku Wei-Chi
Published: October 2004

So far, many strong-password authentication schemes have been proposed, however, none is secure enough. In 2003, Lin, Shen, and Hwang proposed a strong-password authentication scheme using smart cards, and claimed that their scheme can resist the guessing attack, the replay attack, the impersonation attack, and the stolen-verifier attack. Later, Ku, Tsai, and Chen showed that Lin-Shen-Hwang's scheme suffers from a replay attack and a denial-of-service attack. Herein, we propose a more secure hash-based strong-password authentication scheme without using smart cards.
Secure communications between bandwidth brokers
Authors: Lee Bu-Sung , Woo Wing-Keong , Yeo Chai-Kiat , Lim Teck-Meng , Lim Bee-Hwa , He Yuxiong , Song Jie
Published: October 2004

In the Differentiated Services (DiffServ) architecture, each domain has a Bandwidth Broker to provide the resources management, primarily bandwidth reservation. In a multi-domain environment, Simple Inter-domain Bandwidth Broker Signaling (SIBBS) protocol is proposed for the inter-domain communication protocol proposed for bandwidth broker communication. Since the information exchanged between BBs are sensitive in sense of Service Level Agreement (SLA), the communications between the inter-domain bandwidth brokers should be protected from attacks. This paper presents the incorporation of the Public Key Infrastructure (PKI) security model for SIBBS. A prototype system with the security elements as well as the implementation of the SIBBS was successfully developed and tested.
Distributed mutual exclusion algorithms in mobile ad hoc networks
Authors: Benchaïba M. , Bouabdallah A. , Badache N. , Ahmed-Nacer M.
Published: October 2004

The problem of mutual exclusion has been extensively studied in distributed systems. The proposed solutions can be mainly classified in consensus based and token based protocols. Some of the proposed solutions consider the physical topology of the networks and try to provide optimal message exchange and minimal synchronisation delays. Others, impose a logical structure on the network like a ring or a tree. Recently, the mutual exclusion problem received an interest for mobile ad hoc networks. These networks are known as a challenging domain. To our knowledge, few algorithms have been proposed in the literature and all of them are token based approach. In this paper, we review the distributed mutual exclusion algorithms developed for mobile environments and principally for ad hoc networks and discuss some issues.
The ROLM Ada work center
Authors: Elliott Jon K.
Published: October 2004

On Monday, October 11, 1982 ROLM Corporation announced the ROLM Ada Work Center. This brief article provides additional information about this new Ada system.
Project SPERBER
Authors: Ploedereder Erhard
Published: October 2004

Project SPERBER is concerned with the development of a high-quality software environment facilitating the development of software written in Ada or Basic Pearl. It is to be used for the design. Implementation, maintenance and enhancement of embedded system software. This presentation elaborates on the background that led to project SPERBER, presents its current status and outlines future plans. It also provides an overview of the system structure from the viewpoint of a user.
A problem with Ada and resource allocation
Authors: Wellings A. J. , Keeffe D. , Tomlinson G. M.
Published: October 2004

Ada has been described as being suitable for the implementation of resource management algorithms. We explore four possible solutions to the problem of allocating a number of resources from a pool. We conclude that no ready method presents itself which avoids race conditions and is robust in the face of the failure of requesting tasks.
Runtime organization for the Ada language system programs
Authors: Kamrad J. Michael
Published: October 2004

The runtime organization provides the execution environment for generated code of a source program. The runtime organization includes the primitive data elements, such as scalar and composite data objects; system data elements, such as stack and heaps; and a runtime system to provide functionality not supported in the target computer. In effect the runtime organization provides an abstract or virtual machine.This paper is a brief overview of the runtime organization that is the execution environment for the code generated by the Ada compiler in the Army Ada Language System. Since this compiler translates the full Ada language, the runtime organization must provide support not normally found in other languages, such as exception handling and tasking. As retargetability is a major goal of the Ada Language System, the runtime organization must also exist on many targets, both with or without an operating system support. While this paper specifically describes the runtime organization for the VAX/VMS 11/780, it does explore the design flexibility that enables the design to support generated code over a variety of targets.
Efficient initialisation routines for multiprocessor systems programmed in Ada
Authors: Burns A.
Published: October 2004

As an Ada task cannot be initialised at the time of creation a rendezvous must be used to pass identification data to those tasks that require it. With multiprocessor systems this initialisation phase can be a source of inefficiency as it is, essentially, a sequencial activity. Algorithms, and code, are presented that remove this potential bottleneck by involving all tasks in the initialisation process. Two approaches are discussed; the first delays each active task by a minimum amount (the time it takes to perform two rendezvous), the second method delays all active tasks but initialises the maximum number in any time period. For example 1023 tasks can be initialised in the time taken to perform 10 rendezvous.
On teaching theoretical foundations of computer science
Authors: Mandrioli Dino
Published: October 2004

Theoretical foundations of Computer Science (Automata Theory, Complexity, Formal Languages...) are taught almost everywhere within Computer Science curricula. However little effort is usually done to present this material in an integrated and motivated way, that is in such a way that its application and use in the solution of practical problems appears to any student.A proposal is developed in order to overcome this inadequacy and to emphasize the basic aspects of theoretical Computer Science.
An NP-hard problem in bipartite graphs
Authors: Krishnamoorthy M. S.
Published: October 2004

Checking for Hamiltonian circuit in bipartite graphs is shown to be NP-hard.
Mutual exclusion with linear waiting using binary shared variables
Authors: Burns James E.
Published: October 2004

The problem of mutual exclusion among N asynchronous, parallel processes using only shared binary variables for communication is considered. Upper and lower bounds of N+1 and N shared binary variables, respectively, are shown for the problem of mutual exclusion with linear waiting. Lockout-free mutual exclusion is shown to require at least N shared binary variables when the primitive operations are suitably restricted. This latter bound is tight for N=2.
Running-mode analysis of the Security Socket Layer protocol
Authors: Zhang Yuqing , Liu Xiuying
Published: October 2004

The Secure-Socket Layer (SSL) protocol is analyzed using a formal analysis mehod called the approach of the running-mode analysis. This analysis uncovers successfully some anomalies in the basic SSL handshake protocol. And we give some attacks on these anomalies.
A secure user authentication scheme using hash functions
Authors: Yoon Eun-Jun , Ryu Eun-Kyung , Yoo Kee-Young
Published: October 2004

Recently, Lee et al. proposed an improvement on Peyravian and Zunic scheme to make the protocol withstand the guessing attack. However, their scheme suffers from a denial of service attack. In this paper, we show that an attacker can easily prevent the normal use of communication facilities by performing the attack. We also propose an enhancement of the scheme to isolate such a problem.
A secure one-time password authentication scheme with low-computation for mobile communications
Authors: Lin Min-Hui , Chang Chin-Chen
Published: October 2004

In recent years, m-commerce technology has been maturing. Various mobile devices are now designed to help users reach the servers of service providers and to process tasks such as stock trading, product purchasing, product information collecting, and so on. Once the services are only available to the members, authentication is applied to verify the identities of users. However, most current authentication methods used in m-commerce are designed for wired networks and require high computation costs, making them unsuitable for wireless environments.A one-time password authentication scheme that uses lighter computation and considers the limitations of mobile devices is proposed in this paper. Meanwhile, the proposed scheme is free from replay attacks, server spoofing attacks, off-line dictionary attacks, active attacks, and revelation of message contents.
A server assisted authentication protocol for detecting error vectors
Authors: Lee Cheng-Chi , Hwang Min-Shiang , Liao I-En
Published: October 2004

This article presents a server assisted authentication protocol for RSA signature and two cryptanalysis of the protocol. An improved protocol is also proposed for extending the previous server assisted authentication protocol for RSA signature to detect the one-round active attack.
Multilanguage programming with ada in the .Net environment
Authors: Humphries Jeffrey W. , Carlisle Martin C. , Wilson Terry A.
Published: October 2004

This paper describes our experiences in using Ada with other programming languages in the .NET environment. This paper explains our approach and presents lessons learned during our development of a real-world software project using .NET. We compare and contrast the languages used, justify our language choices, and present details of our efforts.
Static verification and extreme programming
Authors: Amey Peter , Chapman Roderick
Published: October 2004

At first glance, the worlds of high-integrity software engineering and Extreme Programming (XP) seem to have little in common. Somewhat surprisingly, we have found the reverse to be the case-indeed it seems that many practices advocated by the XP community are familiar to us from many years' of experience in building safety- and security-critical systems. This paper discusses our experiences in applying some XP practices in critical projects. Secondly, we discuss how static verification can augment XP, particularly in the Pairwise Programming and Refactoring practices.
AdaSlicer
Authors: Sward Ricky E. , Chamillard A.T.
Published: October 2004

The ability to slice a program or parts of a program is useful in a variety of domains, including re-engineering, dependency analysis, test case generation, test coverage evaluation and debugging. Although a variety of static analysis tools are available to support these activities for Ada programs, none of these tools provide a program slicing capability. Fortuitously, the Ada Semantic Interface Specification (ASIS) provides access to the Ada program information required to slice the program. This paper describes our use of ASIS to implement an Ada program slicer, called AdaSlicer.
A framework for designing and implementing the Ada standard container library
Authors: Marco Jordi , Franch Xavier
Published: October 2004

An open issue of the Ada language is the definition of a standard container library. Containers in this library (e.g., sets, maps and lists) shall offer some core functionalities that characterise their behaviour (i.e., different strategies for managing the elements stored therein) as well as other general functionalities. Among these general functionalities, we are interested in alternative ways for accessing the containers, namely direct access by position and traversals using iterators. In this paper, we present the Shortcut-Based Framework (SBF), a framework aimed at providing suitable, uniform, accurate and secure access by position and iterators, while keeping other nice properties such as comprehensibility and changeability. The SBF should be considered as a baseline upon which the Ada standard container library can be built. We assess the feasibility of our proposal defining a quality model for container libraries and evaluating the SBF using some metrics defined with the Goal-Question-Metric approach.
Measuring cohesion of packages in Ada95
Authors: Xu Baowen , Chen Zhenqiang , Zhao Jianjun
Published: October 2004

Ada95 is an object-oriented programming language. Pack-ages are basic program units in Ada 95 to support OO programming, which allow the specification of groups of logically related entities. Thus, the cohesion of a package is mainly about how tightly the entities are encapsulated in the package. This paper discusses the relationships among these entities based on dependence analysis and presents the properties to obtain these dependencies. Based on these, the paper proposes an approach to measure the package cohesion, which satisfies the properties that a good measure should have.
A complexity-theoretic proof of a Recursion-Theoretic Theorem
Authors: Ben-Amram Amir M.
Published: October 2004

It is well known that Complexity Theory inherited many tools from Recursion Theory. This note is an example where tools from Complexity Theory simplify the proof of a Recursion Theoretical result, illustrating the value of mingling the two subjects.
A stop-and-go queueing framework for congestion management
Authors: Golestani S. J.
Published: October 2004

A framework for congestion management in integrated services packet networks based on a particular service discipline, called
stop-and-go queueing,
is proposed. In this framework, loss-free and bounded-delay transmission is provided to the class of traffic with stringent delay and loss requirements, e.g., real-time traffic, while the bursty traffic without such requirements is treated on a different basis to achieve high transmission efficiency. Loss-free and bounded-delay transmission is accomplished by means of an admission policy which ensures smoothness of the traffic at the network edge, and the stop-and-go queueing which maintains the traffic smoothness throughout the network. Both the admission policy and the stop-and-go queueing are based on a time framing concept, addressed in a previous paper. This concept is further developed here to incorporate several frame sizes into the strategy, thereby providing the necessary flexibility in accommodating throughput and end-to-end delay requirements of different connections on an as-needed basis.
Virtual clock: a new traffic control algorithm for packet switching networks
Authors: Zhang L.
Published: October 2004

A challenging research issue in high speed networking is how to control the transmission rate of statistical data flows. This paper describes a new algorithm, VirtualClock, for data traffic control in high-speed networks. VirtualClock maintains the statistical multiplexing flexibility of pocket switching while ensuring each data flow its reserved average throughput rate at the same time. The algorithm has been tested through simulation.
Dynamic adaptive windows for high speed data networks: theory and simulations
Authors: Mitra D. , Seery J. B.
Published: October 2004

Recent results on the asymptotically optimal design of sliding windows for virtual circuits in high speed, geographically dispersed data networks in a stationary environment are exploited here in the synthesis of algorithms for adapting windows in realistic, non-stationary environments. The algorithms proposed here require each virtual circuit's source to measure the round trip response times of its packets and to use these measurements to dynamically adjust its window. Our design philosophy is quasi-stationary: we first obtain, for a complete range of parameterized stationary conditions, the relation, called the “design equation”, that exists between the window and the mean response time in asymptotically optimal designs; the adaptation algorithm is simply an iterative algorithm for tracking the root of the design equation as conditions change in a non-stationary environment. A report is given of extensive simulations of networks with data rates of 45 Mbps and propagation delays of up to 47 msecs. The simulations generally confirm that the realizations of the adaptive algorithms give stable, efficient performance and are close to theoretical expectations when these exist.
Efficient at-most-once messages based on synchronized clocks
Authors: Liskov B. , Shrira L. , Wroclawski J.
Published: October 2004

This paper describes a new message passing protocol that provides guaranteed detection of duplicate messages even when the receiver has no state stored for the sender. It also discusses how to use these messages to implement higher-level primitives such as at-most-once remote procedure calls and sequenced bytestream protocols, and describes an implementation of at-most-once RPCs using our method. Our performance measurements indicate that at-most-once RPCs can be provided at the same cost as less desirable RPCs that do not guarantee at-most-once execution. Our method is based on the assumption that clocks throughout the system are loosely synchronized. Modern clock synchronization protocols provide good bounds on clock skew with high probability; our method depends on the bound for performance but not for correctness.
A data processing performance model for the OSI application layer protocols
Authors: Shiroshita T.
Published: October 2004

The need for data structure analysis of OSI protocols has increased with the development of OSI protocols into Application layer protocols which require a wide variety of data structures. Especially, when using high speed networks such as FDDI and B-ISDN. Application data processing is liable to be the critical performance factor in the communications based on the OSI frameworks. This paper presents a data processing model to analyze the performance of the Application data receiving process in the Presentation layer. The model is based on a finite pushdown automaton. A scheme is proposed that can determine the memory space and processing time needed by the receiving process for any type of data structure. Consequently, an evaluation method is developed for Application protocols data structures in OSI. The method is then used to evaluate sample data structures commonly used for document transmission.
The DARPA wideband network protocol
Authors: Edmond W. , Leib K. , Topolcic C.
Published: October 2004

This paper discusses the Dual Bus Protocol (DBP) developed for the Terrestrial Wideband Network (TWBNET), a high-speed trans-continental network that supports distributed real-time applications and protocol research. DBP is a descendant of the QPSX protocol proposed as the IEEE 802.6 Metropolitan Area Network (MAN) standard, with enhancements to create a protocol suitable for a wide area network and to provide network services such as reserved bandwidth. In addition, the protocol was designed to be scalable for use in networks that are larger and faster than the TWBNET. This paper describes the DBP and its network environment and provides an analysis of the performance of the protocol based on both simulations and TWBNET measurements.
Gauss: a simple high performance switch architecture for ATM
Authors: de Vries R. J. F.
Published: October 2004

Broadband ISDN will use the Asynchronous Transfer Mode (ATM) as its basic switching, multiplexing and transmission technique. ATM is very flexible and promising, nevertheless, it requires high-performance switching hardware. The ATM Switching Element (ASE) proposed in this paper, called the Gauss ASE, can meet ATM requirements. Using traffic observations and a number of well known design principles the Gauss ASE gets a number of favorable properties, for example the Gauss ASE is nonblocking and has minimum delay and variance of delay. The ASE is kept modular so that it can easily grow towards a large single stage switching fabric using only two types of Integrated Circuits.
Pulsa: non-blocking packet switching with shift-register rings
Authors: Murakami G. J. , Campbell R. H. , Faiman M.
Published: October 2004

This paper discusses the design of a switch for high-speed computer networking at gigabit rates. We present the
Pulsar
switch, a non-blocking design based on a high-spin-rate, port-dedicated, word-parallel, shift-register ring. Several design alternatives address the problem of Head-Of-Line blocking. In contrast to Batcher-Banyan switches, access to the ring is asynchronous which facilitates low delay and arbitrary packet length. The switch can support ATM cells simultaneously with packets sized for applications such as single characters, memory words, disk blocks, memory pages, or video images.
Pulsar
can be used as a high-throughput computer backplane replacement. The design can be implemented with existing high-speed circuit technology.
Shortest paths and loop-free routing in dynamic networks
Authors: Awerbuch B.
Published: October 2004

In this paper, we survey the existing methods for designing shortest paths routing algorithms for dynamic networks. We compare them based on worst-case communication and message complexity, and suggest new approach that yields a protocol with linear time and polynomial communication.

The main idea behind our approach is to use a “dynamic synchronizer”, which transforms a dynamic asynchronous network into static synchronous one. We believe this is an important methodology in design and analysis of communication protocols, that can be applied to other problems as well.
Architectural considerations for a new generation of protocols
Authors: Clark D. D. , Tennenhouse D. L.
Published: October 2004

The current generation of protocol architectures, such as TCP/IP or the ISO suite, seem successful at meeting the demands of todays networks. However, a number of new requirements have been proposed for the networks of tomorrow, and some innovation in protocol structuring may be necessary. In this paper, we review some key requirements for tomorrow's networks, and propose some architectural principles to structure a new generation of protocols. In particular, this paper identifies two new design principles, Application Level Framing and Integrated Layer Processing. Additionally, it identifies the presentation layer as a key aspect of overall protocol performance.
Design of inter-administrative domain routing protocols
Authors: Breslau L. , Estrin D.
Published: October 2004

Policy Routing (PR) is a new area of development that attempts to incorporate policy related constraints on inter-Administrative Domain (AD) communication into the route computation and forwarding of inter-AD packets.

Proposals for inter-AD routing mechanisms are discussed in the context of a design space defined by three design parameters: location of routing decision (i.e., source or hop-by-hop), algorithm used (i.e., link state or distance vector), and expression of policy in topology or in link status. We conclude that an architecture based upon source routing, a link state algorithm, and policy information in the link state advertisements, is best able to address the long-term policy requirements of inter-AD routing. However, such an architecture raises several new and challenging research issues related to scaling.
Topology distribution cost vs. efficient routing in large networks
Authors: Bar-Noy A. , Gopal M.
Published: October 2004

Routing a message in a network is
efficient
(in terms of weight of the path used to carry the message) when nodes know the full topology of the network. This may not be the case in large networks since a network may be composed of smaller autonomous pieces by design or by requirements on performance, with each piece having less than complete information about other pieces. We present a trade-off between the amount of topology information exchanged among these pieces and the efficiency of routing in the network. The large network that we study is a collection of networks connected by boundary nodes. Each boundary node knows the topology of its network and the connectivity of networks to each other. The question addressed here is how much topology information about each network should be distributed to other networks in order to achieve reasonably efficient routing.
Efficient use of workstations for passive monitoring of local area networks
Authors: Mogul J.
Published: October 2004

Effective management of a local area network (LAN) requires not only a protocol to manage the active entities, but also a means to monitor the LAN channel. This is especially true in shared-channel LANs, such as Ethernet, where the behavior of the LAN as a whole may be impractical to deduce from the states of the individual hosts. Passive monitoring can be done using either a dedicated system or a general-purpose system. Dedicated monitors have been favored for several reasons, but recent workstations, when carefully programmed, are sufficiently powerful to serve this function. Using a workstation offers high-performance graphics and a more flexible environment for collecting and presenting LAN behavior.
Performance analysis of FDDI token ring networks: effect of parameters and guidelines for setting TTRT
Authors: Jain Raj
Published: October 2004

Fiber-Distributed Data Interface (FDDI) is a 100-Mbps Local Area Network (LAN) standard being developed by the American National Standards Institute (ANSI). It uses a timed-token access method and allows up to 500 stations to be connected with a total fiber length of 200 km.

We analyze the performance of FDDI using a simple analytical model and a simulation model. The performance metrics of response time, efficiency, and maximum access delay are considered. The efficiency is defined as the ratio of maximum obtainable throughput to the nominal bandwidth of the network. The access delay is defined as the time it takes to receive a usable token.

The performance of FDDI depends upon several workload parameters; for example; the arrival pattern, frame size, and configuration parameters, such as the number of stations on the ring, extent of the ring, and number of stations that are waiting to transmit. In addition, the performance is affected by a parameter called the Target Token Rotation Time (TTRT), which can be controlled by the network manager. We considered the effect of TTRT on various performance metrics for different ring configurations, and concluded that a TTRT value of 8 ms provides a good performance over a wide range of configurations and workloads.
Frame content independent stripping
Authors: Yang H. , Ramakrishnan K. K.
Published: October 2004

Token rings have the property that a station that transmits a frame on the ring is responsible for removing the frame after it has been delivered to the destination stations. The algorithm to perform the frame removal is called 'Frame Stripping'. Most existing algorithms strip frames based on their content. This is not always adequate. The need for a new algorithm arises from the fact that frames transmitted by a station need not have the station's own address as the source address for a variety of reasons - such as when a bridge transmits a frame or when another address is used as the source address by a station instead of its original station address. This paper discusses a new frame content independent stripping (FCIS) algorithm for token rings.

The FCIS algorithm
counts
the number of frames transmitted by the station after capturing the token. In addition, the station places a special delimiter frame at the end of the transmission of frames, before releasing the token. The station then strips all received frames until either the number of frames stripped equals the number of frames transmitted or when either the delimiter frame or a
token
is received. We demonstrate that the FCIS algorithm has a minimal impact on the performance of the ring. We study the robustness of the algorithm to errors and demonstrate that its reliability is as good as the inherent mechanisms of the token ring.

The algorithm studied here is very simple to implement and interoperates with other stations not implementing this algorithm. The algorithm places no topological restrictions on the network and has the attractive feature of removing large fragments and no-owner frames.
An inclusive session level protocol for distributed applications
Authors: Sunderam V. S.
Published: October 2004

The design of an inclusive session level protocol targeted at distributed applications on local networks is presented. The session protocol is motivated by the observation that application requirements, as well as network characteristics, for current and future distributed systems are not well matched to available protocol suites. The nature of services provided in the proposed protocol are derived from typical application requirements, and include group communications, synchronization and recovery, and integrated distributed primitives such as mutual exclusion and consensus. The protocol is also influenced by the characteristics of typical local networks that support sequenced delivery with data integrity, have low latency and high throughput, and are well suited to global addressing schemes. Initial experiences with a test implementation indicate that high level service support is valuable and can be provided with good performance.
Non-stationarity and high-order scaling in TCP flow arrivals
Authors: Uhlig Steve
Published: October 2004

The last decade has been a very fruitful period in important discoveries in network traffic modeling, uncovering various scaling behaviors. Self-similarity, long-range dependence, multifractal behavior and finally cascades have been studied and convincingly matched to real traffic. The first purpose of this paper is to provide a methodology to go beyond the naive analysis of the second-order wavelet-based estimators of scaling, by performing non-stationarity checks and relying on the information contained in the high-order properties of the wavelet coefficients. Then, we apply this methodology to study the scaling properties of the TCP flow arrivals based on several traffic traces spanning the years from 1993 to early 2002. Our study reveals that the second-order scaling properties of this process describe its dynamics quite well. However, our analysis also provides evidence that high-order scaling in this process appears due to pathological behaviors like rate limitation and non-stationarity.
SAKM
Authors: Challal Yacine , Bettahar Hatem , Bouabdallah Abdelmadjid
Published: October 2004

Multicasting is increasingly used as an efficient communication mechanism for group-oriented applications in the Internet. In order to offer secrecy for multicast applications, the traffic encryption key has to be changed whenever a user joins or leaves the system. Such a change has to be communicated to all the current users. The bandwidth used for such rekeying operation could be high when the group size is large. The proposed solutions to cope with this limitation, commonly called
1 affects n
phenomenon, consist of organizing group members into subgroups that use independent traffic encryption keys. This kind of solutions introduce a new challenge which is the requirement of decrypting and reencrypting multicast messages whenever they pass from one subgroup to another. This is a serious drawback for applications that require real-time communication such as video-conferencing. In order to avoid the systematic decryption / reencryption of messages, we propose in this paper an adaptive solution which structures group members into clusters according to the application requirements in term of synchronization and the membership change behavior in the secure session. Simulation results show that our solution is efficient and typically adaptive compared to other schemes.
Modeling wireless links for transport protocols
Authors: Gurtov Andrei , Floyd Sally
Published: October 2004

Wireless links have intrinsic characteristics that affect the performance of transport protocols; these include variable bandwidth, corruption, channel allocation delays, and asymmetry. In this paper we review simulation models for cellular, WLAN and satellite links used in the design of transport protocols, and consider the interplay between wireless links and transport. We argue that the design and evaluation of transport protocols can be improved by providing easily available models of wireless links that strike a balance between realism, generality, and detail.There is an ongoing tussle between wireless link design and transport protocol design, with papers about how wireless link designers should take into account the dynamics of TCP, and other papers about how TCP and other transport protocols can be designed or modified for better performance over current wireless link technologies. In this paper we consider how appropriate models for wireless links can help in this tussle, and in the general design and evaluation of transport protocols over wireless links.
Task state transitions in Ada
Authors: Härtig Hermann , Pfitzmann Andreas , Treff Leo
Published: October 2004

By stepwise refinement a state transition diagram for ADA-tasks is derived. Four steps of refinements are explained and then a complete list of state transitions is given containing reference s and short explanations.
Classical optimizations in Ada
Authors: Davis Mark
Published: October 2004

Ada contains several features which have posed problems for optimizers when included in other languages. These features are subprograms, exception handling, and multi-tasking. They are defined in Ada in such a way that classical optimizations, such as common sub-expression elimination and code motion, are minimally affected. This paper discusses the impact of Ada's semantics on classical optimizations and the information needed for the correct application of these transformations.
The case for full Ada as a design language
Authors: Chase Anna I. , Gerhardt Mark S.
Published: October 2004

This paper proposes the use of Ada for a design language. It suggests the use of full Ada constructs to represent a design which can be rigorously checked both syntactically and semantically. First it reviews the objectives of Ada and of design languages and, discusses the relationship between Ada and the design process, and reviews current design strategies. It cites the constructs of Ada relevant to the design process and surveys rurrent industry PDL efforts. Finally it suggests how to use Ada for design by giving examples of how and when to use appropriate Ada constructs and the appropriate forms hy which to convey the design information.
Interactive
Ada™
in the Arcturus environment
Authors: Standish Thomas A.
Published: October 2004

A
RCTURUS
offers an approach to the integrated use of compiled and interpreted Ada, template-driven Ada text editing, an Ada Program Design Language (PDL), Ada program performance measurement with color profiles, formatted printing of Ada programs with useful listing options, and automated stepwise refinement from Ada program designs written in Ada PDL into executable Ada. This paper has two objectives : (a) to provide a two page thumbnai l sketch of some interactive Ada capabilities in A
RCTURUS
, and (b) to provide a detailed scenario of interactive Ada programming at the very simplest level, using Ada-oriented variants of interactive programming techniques that have proven effective in practice --- th e hope being that the reader will be convinced that
interactive Ada
is an idea worth vigorous further pursuit.
An Ada® language type checking problem and two morals
Authors: Wetherell C. S. , Quinn M. E.
Published: October 2004

A simple type checking problem given to some Ada compilers illustrates some potential problems in compiler design and implementation. We draw two morals for software designers.
Experience with Ada for the Graphical Kernel System
Authors: Gilroy Kathleen
Published: October 2004

This paper describes the effort to produce an Ada language binding to the Graphical Kernel System (GKS) and to implement a subset of the GKS functionality in Ada. It presents an overview of the GKS/Ada project, discusses some of the issues raised during development of the GKS software, describes the results of a post-coding analysis comparing the binding and prototype code, and comments on the lessons drawn from this experience.
A perfect hash function for Ada reserved words
Authors: Wolverton David Alan
Published: October 2004

A fast perfect hash function is presented which allows the 63 Adat reserved words to be differentiated quickly from other Ada identifiers. Such functions are potentially useful in improving the performance of software that processes the text of Ada programs.
The use of structured systems analysis in the rapid creation of Information Management Systems prototypes written in Ada
Authors: Kirkham J. A. , Burns A. , Thomas R. J.
Published: October 2004

The Structured Systems Analysis Methodology is introduced and the requirements specification for a simple Information Management System is documented using Data Flow Diagrams and a Data Dictionary. The transformation of the structured requirements specification into a system prototype using the ADA package, task, generic, exception handling and separat e compilation constructions is described. The future development of the approach is discussed.
Ada software on distributed targets
Authors: Armitage James W. , Chelini James V.
Published: October 2004

Several approaches to developing Ada software for distributed targets have been proposed. This paper presents a survey of four such methods. These fall into two categories : distributed-target compilers and source code distribution. Problems associated with these approaches are identified.