Multiplex communications – Wide area network – Packet switching
Patent
1993-06-04
1994-11-08
Chin, Wellington
Multiplex communications
Wide area network
Packet switching
370 97, H04B 7212, H04B 7185
Patent
active
053633741
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in a general manner to the resource control for satellite telecommunication networks using the asynchronous time-division technique ATM (Asynchronous Transfer Mode).
2. Description of the Prior Art
After the introduction of the services offered by the "narrow-band" integrated service digital networks, the network designers sensed the need to produce a more efficient network in the medium-term. This need was based on the following considerations: a "narrow-band" digital network does not enable complete integration of the existing or "futuristic" telecommunication services. The existing digital networks do not fully satisfy needs as regards data communications with very high bit rate, services generating a traffic flow of a highly sporadical nature, or in the long-term, video communications. The asynchronous time-division technique ATM was thus advocated to meet three requirements: digital technology, high bit rate, and flexibility in the routing of the different types of communications.
An international strategy for the development of "wide-band" integrated service digital networks (WB-ISDN), defined by the CCITT, is based on three fundamental principles: basic element processed by all means constituting the network: terminals, multiplexers and switches. An ATM cell typically comprises 53 bytes, 48 being allocated to the transmission of information and 5 to the routing of the cell in the network, network, and all transfers of information. The mode selected is the "virtual-circuit" mode for the transmission of the cells throught the nodes of the network, of a type comparable to X.25 networks.
The conventional networks using the circuit mode, which is the main component of the "narrow-band" integrated service digital network, solve all of their resource control problems at admission of calls in the network: once a call has been set up, a fixed bit rate resource is reserved for a user. The circuit mode would not of course suit the WB-ISDN network for obvious reasons of under-utilization of the transmission means due to the highly sporadic nature of certain communications.
Conversely, the ATM technique is based upon packet mode communications and therefore on operation in queues. Nevertheless, contrary to the techniques usually used for congestion control in conventional packet networks, an oversizing of the network or a step-by-step control of the traffic between nodes of the network is inconceivable for a wide-band network in which the bit rates can reach a hundred Mb/s. The control mechanisms substantially penalize the transmission times and prove inefficient. A solution consists in posing the problem backwards: if the congestion of the network cannot be controlled (deterioration of transmission times), it must be avoided by means of resource allocating mechanisms when accesses to the network are requested. But this prior condition imposes evaluation of the resource to be reserved as a function of the service: it is as easy to determine a resource to be reserved for a request for a constant or variable bit rate service, as it is difficult to define a resource to be reserved for highly-sporadicalness services.
When a source-user transmits a connection request, the request must contain the address of the destination but also the capacity required to route a traffic associated with the request. This request is routed within the network, from one node to another, according to routes determined by a routing algorithm. The call is accepted if there exists at least one route between the source-user and the destination such that each internodal link of said route has sufficient capacity to satisfy the transmission capacity required by the user. The problem has been stated: what bit rate capacity has to be required to route traffics having highly sporadic flows?
The complete generalization of the capacity of the network makes it difficult to provide an answer, insofar as the connections interact with one another.
Modification of the
REFERENCES:
patent: 4736371 (1988-04-01), Tejima et al.
patent: 5012469 (1991-02-01), Sardana
patent: 5121387 (1992-06-01), Gerhardt et al.
patent: 5197125 (1993-03-01), Engel et al.
patent: 5295140 (1994-03-01), Crisler et al.
Proceedings of the IEEE, vol. 79, No. 2, Feb. 1991, pp. 170-189.
Infococom '89, 23-27 Apr. 1989, vol. 2, pp. 632-640.
Maral Gerard
Seret Dominique
Tondriaux Marc
Zein Al Abedeen Tarif
Chin Wellington
France Telecom
LandOfFree
Method for allocating resources by anticipated reservation in an 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 allocating resources by anticipated reservation in an, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for allocating resources by anticipated reservation in an will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1788552