Multiplex communications – Diagnostic testing – Of a switching system
Reexamination Certificate
1998-09-10
2001-03-20
Pham, Chi H. (Department: 2731)
Multiplex communications
Diagnostic testing
Of a switching system
C370S255000, C370S422000
Reexamination Certificate
active
06205121
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method of establishing logical connections in a synchronous digital communications network having a plurality of at least partially interconnected network elements designed for the transmission of data packets each containing a destination address. It is also directed, to a network element for such a synchronous digital communications network, and to a management system for such a synchronous digital communications network.
BACKGROUND OF THE INVENTION
Data packets, which originate, for example, from local area networks, are transmitted through data networks to respective addressees. Such data packets originate particularly from Internet applications, are structured in accordance with the Internet protocol (IP), and have a source address and a destination address. As transmission media (OSI Layer
1
) for long-haul data communications networks, synchronous digital networks based on the SDH or SONET standards and recommendations are used (SDH=Synchronous Digital Hierarchy, SONET=Synchronous Optical Network). This is stated, for example, in RFC 1619 (W. Simpson, Request for Comments 1619, Internet Engineering Task Force, Network Working Group, May 1994), which proposes to place data packets to be transferred over point-to-point links directly in synchronous transport modules (STM-N) of SDH or synchronous transport signals (STS-N) of SONET.
In synchronous digital communications networks, virtual, i.e., logical, connections can be switched between elements of the network. This is done manually with the aid of a management system. The switched logical connections are then used by routers of different data networks, which provide the gateways to the synchronous digital communications network, to transmit data packets.
Since applications of the Internet, in particular, produce widely time-varying data quantities (between 0 b/s and a few Mb/s) which have to be transmitted over the synchronous digital communications network in the form of IP data packets, the prior art has the disadvantage that either large transmission capacities have to be kept available in the communications network, which then remain unused most of the time, or that bottlenecks occur if several users want to send large amounts of data simultaneously.
In another concept, IP packets are first placed in ATM cells and then transmitted over virtual channel connections through a synchronous digital communications network (SDH or SONET). In an article published by Ipsilon Networks (“IP Switching: The Intelligence of Routing, the Performance of Switching”, Ipsilon Technical White Paper on IP Switching, February 1996, retrievable in the Internet at http://www.ipsilon.com/productinfo/wp-ipswitch.html), a device (IP Switch) is presented which combines the functions of an IP router and an ATM switch. This device is capable of identifying longer-duration sequences of data packets having the same source and destination addresses, so-called flows, by means of an address monitor, and to switch suitable connections for these flows in the hardware. This increases the throughput of data packets through the IP switch and shortens the mean switching time. This, too, has the disadvantage that only predetermined logical connections can be used, which are either underdimensioned or overdimensioned, depending on the current payload.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method whereby a synchronous digital communications network can be better adapted to time-varying data traffic. Further objects of the invention are to provide a network element and a management system for a synchronous digital communications network which are suited for carrying out the method.
One object is attained by a method of establishing logical connections in a synchronous digital communications network comprising a plurality of at least partially interconnected network elements designed for the transmission of data packets each containing a destination address, the method comprising the steps of: monitoring the destination addresses of the data packets to be transmitted; determining a current traffic volume between the individual network elements with the aid of the destination addresses; determining an optimized configuration of logical connections based on the traffic volume and existing logical connections; and updating the logical connections in the synchronous digital communications network with the optimized configuration.
Another object is a network element for a synchronous digital communications network comprising a plurality of at least partially interconnected network elements and designed for the transmission of data packets, the network elements comprising: means for monitoring destination addresses of the data packets to be transmitted; and an interface to a central management system for sending messages containing the destination addresses of the data packets to be transmitted and for receiving instructions relating to logical connections to be switched, the central management system being provided for establishing the logical connections in the communications network.
A further object is a management system for a synchronous digital communications network comprising a plurality of at least partially interconnected network elements and designed for the transmission of data packets, the management system comprising: interfaces to the network elements of the synchronous digital communications network for receiving messages containing destination addresses of the data packets to be transmitted and for sending to the network elements instructions relating to logical connections to be switched; means for determining a current traffic volume between the network elements based on the messages containing the destination addresses of the data packets to be transmitted; means for determining an optimized configuration of logical connections between the network elements based on the existing logical connections and the traffic volume; and means for sending to the network elements instructions relating to the logical connections to be switched in accordance with the optimized configuration.
One advantage of the invention is that transmission capacities can be better utilized for the transmission of data packets and that the average transmission rate is higher than in the prior art. Other advantages are that commercially available IP routers can be used, and that no changes to the equipment of a user wishing to transmit data packets over the communications network are necessary.
In a preferred embodiment of the invention, source-address monitoring is additionally performed. This makes it possible to determine charges for transmitted data packets.
In another preferred embodiment of the invention, data packets with predetermined source or destination addresses, e.g., all data packets from or for an individual, predetermined user, are given a higher priority during transmission.
REFERENCES:
patent: 4926419 (1990-05-01), Whipple
patent: 5103447 (1992-04-01), Takiyasu et al.
patent: 5251239 (1993-10-01), Turban et al.
patent: 5311506 (1994-05-01), Biesel
patent: 5315594 (1994-05-01), Noser
patent: 5357504 (1994-10-01), Siegmund
patent: 5430729 (1995-07-01), Rahnema
patent: 5633869 (1997-05-01), Burnett et al.
patent: 5784376 (1998-07-01), Le Gall
patent: 5818842 (1998-10-01), Burwell et al.
patent: 5835710 (1998-11-01), Nagami et al.
patent: 5864536 (1999-01-01), Foglar
patent: 5898668 (1999-04-01), Shaffer
patent: 5953338 (1999-09-01), Ma et al.
patent: 6028860 (2000-02-01), Laubach et al.
patent: 3210462 (1983-09-01), None
patent: 4304916 (1994-08-01), None
patent: 19505905 (1995-10-01), None
patent: 19531611 (1996-11-01), None
patent: 2728122 (1996-06-01), None
Alexander Gersht et al., “Integrated Traffic Management in SONET-Based Multi-Service Networks,” inTeletraffic and Datatraffic in a Period of Change, Elsevier Science Publishers, Holland, 1991.
J. Cornu et al., “Synchronous Networks” inElectrical Communication[ISSN 0013-4252] published by Alcatel NV. Paris,
Alcatel
Oliver Milton
Pham Chi H.
Ware Fressola Van der Sluys & Adolphson LLP
Yao Kwang B.
LandOfFree
Method of establishing logical connections in a synchronous... 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 of establishing logical connections in a synchronous..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of establishing logical connections in a synchronous... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2498856