Na study of non-blocking switching networks pdf

The most familiar use of switches of this type is in a telephone exchange. Overview and definitions non blocking vs blocking switches input vs output queueing simulation model performance of the various architectures. Journal of computer and system sciencfs 17, 145162 1978 on rearrangeable and non blocking switching networks nicholas pippenger mathematical sciences department, ibm thomas j. Openflow is a great concept, but its original design imposes excessive overheads. Sometimes for high end switches non blocking is also refereed to switch architecture ability to significantly reduce head of line blocking hol blocking. Version 2, cse iit kharagpur page 5 module 4 switched communication networks version 2, cse iit kharagpur lesson 1 switching techniques. The switching network may be designed to provide n2 simultaneous switching paths, in which case the network is said to be nonblocking. Lecture 4 wide area networks circuit switching and packet switching 1 switched communications networks switching nodes provide a switching facility that move data between nodes stations devices attached to the network nodes switching devices that provide communication connected by transmission links dedicated pointtopoint. A nonblocking minimal spanning switch is a device that can connect n inputs to n outputs in any combination. The mathematical theory of nonblocking switching networks by. Modelling the blocking behavior of multicast clos networks. Sometimes for high end switches nonblocking is also refereed to switch architecture ability to significantly reduce headofline blocking hol blocking. This paper describes a method of designing arrays of crosspoints for use in telephone switching systems in which it will always be possible to establish a connection from an idle inlet to an idle outlet regardless of the number of calls served by the system. I more users than actual circuits available in network i may be unable to connect users in periods of high use because all circuits are busy i usually acceptable although inconvenient for voice tra c non blocking network.

We investigate networks composed of digital switching matrices. Largescale strictly nonblocking snb and widesense nonblocking wsnb networks may be infeasible due to their high cost. Network blocking vs non blocking architecture student cpu. Strictly nonblocking operation of 3stage clos switching networks. Pdf modelling the blocking behavior of multicast clos networks. Hwang, rearrangeability of multiconnection three stage clos networks, networks, 2. Lecture 4 wide area networks circuit switching and packet. However, rnb networks are not suitable for circuit switching. If the switching bus, or switching components cannot handle the theoretical total of all ports the switch is considered a blocking switch. On rearrangeable and nonblocking switching networks. On rearrangeable and nonblocking switching networks nicholas pippenger. Nonblocking switches take a switchs specifications and add up all the ports at theoretical maximum speed, then you have the theoretical sum total of a switches throughput. Understand the need for circuit switching specify the components.

It has nothing to do with how much throughput the switch can handle. Analyzing nonblocking switching networks using linear. This paper considers threestage switching networks able to support multicast traffic, i. Blocking and nonblocking multirate clos switching networks. Typically, when discussingreferring to non blocking, a crossbar switch fabric is used as an example. Nonblocking folded architectures for multirate atm. Blocking networks are used because not all users require service simultaneously. The analysis done in this paper determines the minimum number of the second stage switches required for the strictly nonblocking operation of such networks. Take a switchs specifications and add up all the ports at theoretical maximum speed, then you have the theoretical sum total of a switches throughput. In telecommunications, a network that has fewer transmission paths than would be required if all users were to communicate simultaneously. In general, there are four kinds of blocking property for switching networks. Nonblocking switch internal bandwidth can handle all the port bandwidths, at the same time, at full capacity. Du, performance of split routing algo rithm for threestage multicast networks, ieeeacm. Theoretically, connecting all cluster nodes via a single nonblocking switch provides the best performance.

Tst switch, strictly nonblocking network, rearrangeably nonblocking network. The 2dilated flattened butterfly 2dfb is a non blocking version of a flattened butterfly network that has been proposed for distributed switching networks 7. Index terms atm, clos networks, multirate switching, nonblocking switches, routing. Clos, a study of nonblocking switching networks, bell system tech. The first edition of this book covered in depth the mathematical theory of nonblocking multistage interconnecting networks, which is applicable to both communication and computer networks. I have a run of the mill 10100 unmanaged switch and a 10100 unmanaged switch. An extension of the classical theory of nonblocking networks is identified and studied that is applicable to multirate circuit and fast packetatm switching systems. On nonblocking multiconnection networks composed of.

Full text of telecommmunication switching systems and networks thiagarajan viswanathan text see other formats. Typically, when discussingreferring to nonblocking, a crossbar switch fabric is used as an example. In the paper we study the conditions under which multiconnection networks are nonblocking. Charles clos a study of nonblocking switching net works, the bell system technical journal, vol. The clos networks not only played a central role in classical circuitswitching theory 3, 4, but also were the bedrock of multirate switching 510 e. A study of nonblocking switching networks abstract. Strictly nonblocking operation of 3stage clos switching. Blocking or nonblocking an important characteristic of a circuitswitching device is whether it is blocking or nonblocking blocking occurs when the network is unable to connect stations because all paths are in use a blocking network allows this used on voice systems short duration calls nonblocking network.

A nonblocking switching network and routing algorithms for. May 20, 2015 version 2, cse iit kharagpur page 5 module 4 switched communication networks version 2, cse iit kharagpur lesson 1 switching techniques. Jp dufey, performance of switching networks 16 23 june 9, 1999 event building. Switching needed for big networks internetworking externality circuit packet vc. Journal of computer and system sciences 17, 145162 1978 on rearrangeable and non blocking switching networks nicholas pippenger mathematical sciences department, ibm thomas j. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. In contrast, rearrangeable nonblocking rnb networks are more scalable because of their much lower cost. In addition, multicast packets are only stored once, further. By providing a highbandwidth core, the switch architecture can be made simpler than competing devices.

Nonblocking at fullsized frames 1518 bytes might not always be nonblocking at 64 byte frames. Introduction in 1953 clos 12 published a seminal paper that gives the construction for a class of networks. Classifying devices although from the outside a switching hub looks very much like a repeating hub, they are from different classes of equipment. Scalable and practical nonblocking switching networks. Therefore, each input signal can be switched to one individual output port. A blocking matrix switch is built with switches on both the inputs and the outputs.

Introduction the two most important architectures for designing non blocking switching networks are clostype 1 and banyantype 2. A nonblocking algorithm is lockfree if there is guaranteed systemwide progress, and waitfree if there is also guaranteed perthread progress. Our analysis determines bounds for the minimum number of middlestage switches required for strictly nonblocking operation. If an application requires an input to be available to more than one output simultaneously, then a non blocking matrix becomes necessary. Circuit switching version 2, cse iit kharagpur specific instructional objectives at the end of this lesson the student will be able to. Both sufficient and necessary conditions are proved. Non blocking switch internal bandwidth can handle all the port bandwidths, at the same time, at full capacity. Non blocking circuit switched networks blocking network. A symmetric threestage clos network is shown in fig. In this paper, the concept of virtual nonblockingness is introduced. The word nonblocking was traditionally used to describe telecommunications networks that could route a connection through a set of relays without having to rearrange existing calls, see clos. The switching capacity should be substantially higher than the line capacity to ensure nonblocking switching between any two ports. This eliminates the complexity of ingress voqs and the extra memory they require.

Communication and networking circuit and packet switching basics. In particular, we concentrate on the strictly nonblocking mode of operation of these switching networks. It will have n inputs to m outputs relating to some n. A clos network 12 is strictly nonblocking for circuit switching if and only if the number of secondstage. Ocp supports optional perthread flow control, enabling the delivery of fully non blocking interfaces in a manner analogous to virtual channels with virtual flit flow control 3. An analysis of blocking versus nonblocking flow control in. The term non blocking means that if it is not defective, it can always make the connection. This comprehensively updated version puts more emphasis to the multicast and multirate networks which are under fast development recently due to their wide. The nonblocking conditions for this network are studied under the assumption of absence of any optimized routing of the connections inside the structure the so.

This paper studies the nonblocking switching operation of onesided twostage switching networks in the multirate environment. The highest layer in ocp is the thread, which defines sequences of transactions that are unordered with respect to transactions on other threads. The mathematical theory of nonblocking switching networks. Fixed size event fragments event building of fixed size event fragment on nonblocking switches selforganization and 100% throughput still true on switching fabrics with internal blocking if the sources gain access to the network in fixed sequential order. This paper studies the nonblocking switching operation of 3stage clos networks in the multirate environment. The general idea is to build a larger switch out of smaller switch modules. T h e possibility of the adoption of this direct design method is important. Blocking and nonblocking socket io network programming. We can call setblocking1 to set up blocking or setblocking0 to unset blocking. A multiconnection network deals with the connections of pairs t 1, t 2 where t 1 is a subset of the input terminals and t 2 is a subset of the output terminals. Nonblocking switches take a switchs specifications and add up all the ports at theoretical maximum speed, then you have the theoretical sum total of a switchs throughput. Existing networks 155 by differentiation, conditions for obtaining minimum numbers of crosspoints can be determined.

We shall study the problem of building a switching network for a telephone exchange with the minimum possible cost. A new design for widesense nonblocking multicast switching. The switching capacity of a system consists of the total bandwidth for all linecard connections and internal switching connections throughout the system. Institute of digital and computer systems tkt9636 sanna maatta nonblocking networks 02. Next 10 a scalable, commodity data center network architecture by. Chapter 4 strictly nonblocking networks sciencedirect. If an application requires an input to be available to more than one output simultaneously, then a nonblocking matrix becomes necessary. Theoretically, connecting all cluster nodes via a single non blocking switch provides the best performance. A switch is strictly nonblocking 11, if a connection can always be set up between any idle input and output without the need to rearrange the paths taken by existing connections. A switch is said to be non blocking if the switching fabric is capable of handling the theoretical total of all ports, such that any routing request to any free output port can be established successfully without interfering other traffics. What is blocking network hindi this feature is not available right now. Nonblocking, multirate, switching, linear programming, duality, dynamic weighted edge coloring. Quantum switching networks based on n n nonblocking benes network 1 authors name.

Watson research center, yorktown heights, new york 10598 received april 25, 1977. If you study the osi communications model, you will notice seven distinct layers corresponding to different communication services. The switching capacity should be substantially higher than the line capacity to ensure non blocking switching between any two ports. Easy lookup less efficient longest prefix match switch functions. Blocking and nonblocking i was wondering what is the way to determine if a catalyst switch is blocking or nonblocking.