45,289 research outputs found
Cell Utilization Efficiency of Internet Protocol Traffic over Asynchronous Transfer Mode Networks
In the near future, large computer networks will be connection oriented,
with at least the data link connectivity being provided by the Asynchronous
Transfer Mode.
(ATM) networks. However, these networks may have to
communicate with the existing network which predominantly use Internet
Protocol (IP). Running Internet Protocol over Asynchronous Transfer Mode
Network has been a contentious issue due to the inefficient segmentation of
Internet Protocol packets into Asynchronous Transfer Mode (ATM) cells. In
this thesis, the current protocols and standards pertaining to Internet
Protocol over Asynchronous Transfer Mode are discussed and overheads
involved in placing Internet Protocol packets into Asynchronous Transfer
Mode cells, taking Logical Link Control/Sub Network Attachment Point
Encapsulation into consideration, are analysed to find out the cell utilization
of Asynchronous Transfer Mode cell in carrying the Internet Protocol
packets. The Wide Area Network (WAN) oriented traffic for our analysis is
collected from the Internet Traffic Archive. Analysis of the trace results show that the Asynchronous Transfer Mode
cell utilisation is better in carrying the user information if the Internet
Protocol packet are sizes larger. It is observed that ranges of Internet
Protocol packets require similar number of Asynchronous Transfer Mode
cells. At small values of Internet Protocol packets, the efficiency of
Asynchronous Transfer Mode cell in carrying the user information is
significantly low due to the Logical Link Control Encapsulation, padding and
the trailer overheads. The Asynchronous Transfer Mode Cell utilization is
better in Virtual Circuit (VC) based multiplexing, saving 8 bytes of
encapsulation for each packet, thus improving the Asynchronous Transfer
Mode (ATM) cell utilization marginally. It is seen that 80% of the Internet
Protocol packet length varies from 54 to 200 bytes for which cell utilisation
varies from 50%-to 82%. However, the average cell utilisation is 84% in the
20,000 packets observed since 20% of the Internet Protocol packet length is
greater than 1000 bytes
Source Behavior for ATM ABR Traffic Management: An Explanation
The Available Bit Rate (ABR) service has been developed to support data
applications over Asynchronous Transfer Mode (ATM) networks. The network
continuously monitors its traffic and provides feedback to the source end
systems. This paper explains the rules that the sources have to follow to
achieve a fair and efficient allocation of network resources.Comment: IEEE Communications Magazine, November 1, 1996, vol 34, no11, pp50-5
Performance and Buffering Requirements of Internet Protocols over ATM ABR and UBR Services
The Asynchronous Transfer Mode (ATM) networks are quickly being adopted as
backbones over various parts of the Internet. This paper analyzes the
performance of TCP/IP protocols over ATM network's Available Bit Rate (ABR) and
Unspecified Bit Rate (UBR) services. It is shown that ABR pushes congestion to
the edges of the ATM network while UBR leaves it inside the ATM portion.Comment: IEEE Communications Magazine, Vol 36, no 6, pp152-15
Saturation routing for asynchronous transfer mode (ATM) networks
The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that the overall effect on performance when using saturation routing is not significant over ATM networks. Then saturation routing ATM implementation is also provided, with important extensions to services such as multicast routing.
After an analytical comparison, in terms of routing overhead, is made between Saturation Routing and the currently proposed Private Network-Network Interface (PNNI) procedure for ATM routing made by the ATM forum. This comparison is made for networks of different sizes (343node and 2401 -node networks) and different number of hierarchical levels (3 and 4 levels of hierarchy). The results show that the higher the number of levels of hierarchy and the farthest (in terms of hierarchical levels) the source and the destination nodes are from each other, the more advantageous saturation routing becomes. Finally, a set of measures of performance for use by saturation routing (or any routing algorithm), as metrics for routing path selection, is proposed. Among these measures, an innovative new measure of performance derived for measuring quality of service provided to Constant Bit Rate (CBR) users (e.g., such as voice and video users) called the Burst Voice Arrival Lag (BVAL) is described and derived
Asynchronous transfer mode link performance over ground networks
The results of an experiment to determine the feasibility of using asynchronous transfer mode (ATM) technology to support advanced spacecraft missions that require high-rate ground communications and, in particular, full-motion video are reported. Potential nodes in such a ground network include Deep Space Network (DSN) antenna stations, the Jet Propulsion Laboratory, and a set of national and international end users. The experiment simulated a lunar microrover, lunar lander, the DSN ground communications system, and distributed science users. The users were equipped with video-capable workstations. A key feature was an optical fiber link between two high-performance workstations equipped with ATM interfaces. Video was also transmitted through JPL's institutional network to a user 8 km from the experiment. Variations in video depending on the networks and computers were observed, the results are reported
A Novel Simulation Based Methodology for the Congestion Control in ATM Networks
© ASEE 2009In this project, we use the OPNET simulation tool for modeling and analysis of packet data networks. Our project is mainly focused on the performance analysis of Asynchronous transfer mode (ATM) networks. Specifically, in this project, we simulate two types of high-performance networks namely, Fiber Distributed Data Interface (FDDI) and Asynchronous Transfer Mode (ATM). In the first type of network, we examine the performance of the FDDI protocol by varying network parameters in two network configurations. In the second type, we build a simple ATM network model and measure its performance under various ATM service categories. Finally, we develop an OPNET process model for leaky bucket congestion control algorithm and examine its performance and its relative effect on the traffic patterns (loss and burst size) in an ATM network. Our simulation results show that the ATM network has longer response time than FDDI. On the other hand, it shows that for both token ring and MAC delay, ATM is shorter than FDDI
Transmission of variable bit rate video over an Orwell ring
Asynchronous Transfer Mode (ATM) is fast emerging as the preferred information
transfer technique for future Broadband Integrated Services Digital Networks (BISON),
offering the advantages of both the simplicity of time division circuit switched techniques
and the flexibility of packet switched techniques. ATM networks with their inherent rate
flexibility offer new opportunities for the efficient transmission of real time Variable Bit
Rate (VBR) services over such networks. Since most services are VBR in nature when
efficiently coded, this could in turn lead to a more efficient utilisation of network resources
through statistical multiplexing. Video communication is typical of such a service and could
benefit significantly if supported with VBR video over ATM networks. [Continues.
Динамические задачи структурного синтеза компьютерных сетей с технологией АТМ и методы их решения
Cформульовані нові задачі структурного синтезу комп’ютерних мереж АТМ (Asynchronous Transfer Mode) з урахуванням динаміки їх розвитку та наданих капітальних вкладень за етапами.The new problems of ATM computer networks structural synthesis with the account of dynamics of their development are considered. The algorithms of their solution are suggested. The experimental investigations of the algorithm are presented out at the example of Ukrainian global network design
Distributed Failure Restoration for Asynchronous Transfer Mode (ATM) Tactical Communication Networks
Asynchronous Transfer Mode (A TM) is an attractive choice for future military
communication systems because it can provide high throughput and support multi-service
applications. Furthermore its use is consistent with the 'off the shelf technology
policy that is currently operated by the Defence Engineering Research Agency of Great
Britain. However, A TM has been developed as a civil standard and is designed to
operate in network infrastructures with very low failure rates. In contrast, tactical
networks are much less reliable. Indeed tactical networks operate on the premise that
failures, particularly node failures, are expected. Hence, efficient, automatic failure
restoration schemes are essential if an A TM based tactical network is to remain
operational. The main objective of this research is the proposal and verification of one
or more new restoration algorithms that meet the specific requirements of tactical
networks.
The aspects of ATM networks that influence restoration algorithms' implementation are
discussed. In particular, the features of A TM networks such as the concept of Virtual
Paths Virtual Channels and OAM (Operation And Maintenance) mechanisms that
facilitate implementation of efficient restoration techniques. The unique characteristics
of tactical networks and their impact on restoration are also presented.
A significant part of the research was the study and evaluation of existing approaches to
failure restoration in civil networks. A critical analysis of the suitability of these
approaches to the tactical environment shows no one restoration algorithm fully meets
the requirements of tactical networks. Consequently, two restoration algorithms for
tactical A TM networks, DRA-TN (Dynamic Restoration Algorithm for Tactical
Networks) and PPR-TN (Pre-planned Restoration Algorithm for Tactical Networks), are
proposed and described in detail. Since the primary concern of restoration in tactical
networks is the recovery of high priority connections the proposed algorithms attempt to
restore high-priority connections by disrupting low-priority calls. Also, a number of
additional mechanisms are proposed to reduce the use of bandwidth, which is a scarce
resource in tactical networks.
It is next argued that software simulation is the most appropriate method to prove the
consistency of the proposed algorithms, assess their performance and test them on
different network topologies as well as traffic and failure conditions.
For this reason a simulation software package was designed and built specifically to
model the proposed restoration algorithms. The design of the package is presented in
detail and the most important implementation issues are discussed. The proposed
restoration algorithms are modelled on three network topologies under various traffic
loads, and their performance compared against the performance of known algorithms
proposed for civil networks. It is shown that DRA-TN and PPR-TN provide better
restoration of higher priority traffic. Furthermore, as the traffic load increases the
relative performance of the DRA-TN and PPR-TN algorithms increases. The DRA-TN
and PPR-TN algorithms are also compared and their advantages and disadvantages
noted.
Also, recommendations are given about the applicability of the proposed algorithms,
and some practical implementation issues are discussed. The number of problems that
need further study are briefly described.Defence Engineering Research Agency of Great Britai
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