Multiplex communications – Data flow congestion prevention or control – Control of data admission to the network
Reexamination Certificate
1997-03-31
2001-04-24
Chin, Wellington (Department: 2731)
Multiplex communications
Data flow congestion prevention or control
Control of data admission to the network
C370S412000, C370S252000
Reexamination Certificate
active
06222822
ABSTRACT:
FIELD OF THE INVENTION
The present invention deals with a method and system for optimizing a digital transmission network operation by tracking transient errors and monitoring and controlling data traffic accordingly, in a network node. More particularly, the invention relates to high speed packet switching transmission networks.
BACKGROUND OF THE INVENTION
The evolution of the telecommunications in general and of the packet switching networks in particular is driven by many factors among which two are worth emphasizing: technologies and applications.
Communication technologies have realized these last years considerable progress with:
the maturing of new transmission media and specially of optical fiber. High speed rates can now be sustained with very low bit error rates. For example, the very important bandwidth provided by optical connections, their low attenuation and their high transmission quality are turned into profit for long distance networks as well as for high rate local networks.
the universal use of digital technologies within private and public telecommunications networks.
The emergence of high speed transmission entails an explosion in the high bandwidth connectivity. The advent of these new technologies has pushed the speed of communication links to the area of the giga-bit per second representing an increase of several orders of magnitude over typical links in traditional networks. The increase of the communication capacity is generating more attractive tariffs and large bandwidths are economically more and more attractive.
On the other hand, in relation with these new emerging technologies, many potential applications that were not possible before are now becoming accessible and attractive. In this environment, three generic requirements are expressed by the users:
Improving old applications. Sub-second response times, which are achievable on low cost personal computers, have raised user expectations so that the lengthy wide area networks response times that were acceptable some years ago are today no longer tolerable. The user interface can be bettered, for example, with fast response full screen applications.
Optimizing communication networks. There is a need for rationalizing the many disparate networks that major users have. Investments can be optimized by integrating heterogeneous traffics like voice, video, and data over the same transport facilities regardless of protocols. Users want the opportunity to control their networking cost by choosing among the different price/performance options offered by the variety of vendors and carriers and to maximize their ability to take advantage of applications built on top of disparate underlying network technologies. However, the motivation for rationalization is not only to save money on links but also to provide a better networking service by integrating the many disparate networks into a single coherently managed unit.
Doing new applications. Emerging applications like graphic, image, video, and multimedia processing are requiring a very large volume of traffic. These new applications that were not feasible (or even thinkable) before are now accessible and generating an ever-increasing demand on bandwidth.
Data transmission is now evolving with a specific focus on applications and by integrating a fundamental shift in the customer traffic profile. Driven by the growth of workstations, the local area networks interconnection, the distributed processing between workstations and super computers, the new applications and the integration of various and often conflicting structures—hierarchical versus peer to peer, wide versus local area networks, voice versus data—the data profile has become more bandwidth consuming, bursting, non-deterministic, and requires more connectivity.
Based on the above, there is strong requirement for supporting distributed computing applications across high speed networks that can carry local area network communications, voice, video, and traffic among channel attached hosts, business engineering workstations, terminals, and small to intermediate file servers.
This vision of a high speed multiprotocol network is the driver for the emergence of fast packet switching networks architectures in which data, voice, and video information is digitally encoded, chopped into small packets and transmitted through a common set of nodes and links. This high speed packet switching network includes nodes interconnecting high speed links (lines or trunks) for orienting the traffics of a great number of users toward preassigned paths each establishing a connection between two end users. Given the high bandwidth over said links, hundreds of connections are supported by each link, and thus handled in each network node. One may therefore easily imagine how catastrophic the consequences of any transmission error that would jam the network, and possibly put the whole system down, would be. This certainly does emphasize the importance of early detecting these errors, particularly when they are of a transient nature, and reorganizing the network traffic accordingly. The present invention shall focus on that.
An efficient transport of mixed traffic streams on very high speed line means for these new network architectures, a set of requirements in terms of performance and resource consumption which can be summarized as follows:
a very large flexibility to support a wide range of connectivity options,
a very high throughput and a very short packet processing time,
an efficient flow and congestion control.
In high speed networks, the nodes must provide a total connectivity. This includes attachment of the user's devices, regardless of vendor or protocol, and the ability to have the end user communicate with any other device. The network must support any type of traffic including data, voice, video, fax, graphic or image. The nodes must be able to take advantage of all common carrier facilities and to be adaptable to a plurality of protocols. All needed conversions must be automatic and transparent to the end user.
One of the key requirements of high speed packet switching networks is to reduce the end-to-end delay in order to satisfy real time delivery constraints and to achieve the necessary highnodal throughput for the transport of voice and video.
Increases in link speeds have not been matched by proportionate increases in the processing speeds of communication nodes and the fundamental challenge for high speed networks is to minimize the packet processing time within each node. In order to minimize the processing time and to take full advantage of the high speed/low error rate technologies, most of the transport and control functions provided by the new high bandwidth network architectures are performed on an end-to-end basis. The flow control and particularly the path selection and bandwidth management processes are managed by the access points of the network which reduces both the awareness and the function of the intermediate nodes.
Communication networks have at their disposal limited resources to ensure an efficient packets transmission. An efficient bandwidth management is essential to take full advantage of a high speed network. While transmission costs per byte continue to drop year after year, transmission costs are likely to continue to represent the major expense of operating future telecommunication networks as the demand for bandwidth increases.
Thus considerable efforts have been spent on designing flow and congestion control processes, bandwidth reservation mechanisms, routing algorithms to manage the network bandwidth.
An ideal network should be able to transmit a useful traffic directly proportional to the traffic offered to the network and this as far as the maximum transmission capacity is reached. Beyond this limit, the network should operate at its maximum capacity whatever the demand is. In the reality, the operations diverge from the ideal for a certain number of reasons which are all related to the inefficient allocation of ressources in overloaded environment.
For the operating t
Gerardin Pierre
Massi Patrick
Spagnol Victor
Cesari & McKenna
Chin Wellington
Cisco Systems Incorporated
Nguyen Steven
LandOfFree
Method for optimizing a digital transmission network... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for optimizing a digital transmission network..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for optimizing a digital transmission network... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2492161