G. Agrawal, B. Chen, and W. Zhao, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," in Proc. 12th IEEE Int. Conf. Distributed Computing Systems, June 1992, pp. 468--475.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....bandwidth allocation, which means that if a master station receives a late token (real token rotation time greater than target token rotation time) then only one high priority (synchronous) message will be transmitted. As a consequence, real time approaches such as those described in, e.g. [6 8] can not be applied to the case of PROFIBUS networks. PROFIBUS networks are widely used, with several hundreds of thousands of installations currently in operation worldwide. Recently, the timing properties of the protocol have been a focus of research. In [10] the authors suggest two different ....

Agrawal, G., Chen, B., Zhao, W. and Davari, S., "Guaranteeing Synchronous Message Deadline with the Timed Token Medium Access Control Protocol", IEEE Transactions on Computers, Vol. 43, No. 3, pp. 327-339, 1994.

....heterogeneous communication subsystems with both time triggered and event triggered protocols. Work in the area of scheduling and schedulability analysis diversified by considering particular communication protocols, like the Token Ring protocol [SM89, Ple92] the FDDI network architecture [ACZD94] the ATM protocol [EHS97, HST97] CAN bus [THW94, DF01] or TTP bus 92] For the case when the tasks are dynamically scheduled on the processors in a multi processor system, according to an EDF task priority assignment, the reader is referred to the work of Spuri [Spu96a, Spu96b] 2.2 Systems ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari. Guaranteeing synchronous message deadlines with the timed token medium access control protocol. IEEE Transactions on Computers, 43(3), March 1994.

....delay. This will allow us to model an internetwork in a hierarchical way. A subnetwork, as long as it can bound its end to end delay, can be modeled as a logical link at the immediately higher internetworking level [26] Various algorithms can be used to bound delay in subnetworks. For example, in [3, 4], algorithms are designed to bound packet delays in an FDDI network. It should be noted that most of the current delay bounding solutions assume a simple network model where link delays between switches are constant [20, 21, 51, 66, 68, 38, 6] Constant delay links have the desirable property ....

Gopal Agrawal, Baio Chen, Wei Zhao, and Sadegh Davari. Guaranteeing synchronous message deadline with the timed token protocol. In Proceedings of IEEE International Conference on Distributed Computing Systems, June 1992.

.... large number of applications (such as incorporation of uncompressed video streams in control loops for remote laboratoring) a number of very high speed networking technologies are currently under investigation for their applicability to support hard real time communication, such as ATM [2] FDDI [1], HIPPI [3] We are investigating the applicability of wormhole routed network technologies for this class of applications. As exemplified by recently developed technology, wormhole routed networks are a promising approach for high bandwidth, low latency communication for small and medium sized ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. In IEEE Computer, Vol. 43. No. 3, March 1994.

....The timing properties of the timed token protocol were first formally analyzed by Johnson and Sevcik in [4, 5] where it is shown that the average token rotation time is bounded by the Target Token Rotation Time (TTRT ) and the maximum token rotation time cannot exceed twice the TTRT . Chen et al. [1, 6, 7, 8] made a detailed study on the timing behavior of the timed token protocol and generalized the upper bound derived by Johnson and Sevcik on the maximum token rotation time. That is, they extended the upper bound on the time possibly elapsed between any two successive token s arrivals at a node ....

G. Agrawal, B.Chen, W.Zhao, and S.Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol," in Proceedings of the 12th IEEE Int'l Conf. on Distributed Computing Systems, June 1992.

.... many network standards including the Fiber Distributed Data Interface (FDDI) IEEE 802.4, the High Speed Data Bus (HSDB) the High Speed Ring Bus (HSRB) and the Survivable Adaptable Fiber Optic Enbedded Networks (SAFENET) which are used as backbone networks in many embedded real time applications [1]. The important concept of the timed token protocol was first proposed by Grow in [2] where the framework (the basic idea) of the timed token protocol, adaptable to either a physical or a logical ring, was described. Ulm [3] then studied the protocol proposed by Grow and its performance ....

....The timing properties of the timed token protocol were first formally analyzed by Johnson and Sevcik in [4, 5] where it is shown that the average token rotation time is bounded by the Target Token Rotation Time (TTRT ) and the maximum token rotation time cannot exceed twice the TTRT . Chen et al. [1, 6, 7, 8] made a detailed study on the timing behavior of the timed token protocol and generalized the upper bound derived by Johnson and Sevcik on the maximum token rotation time. That is, they extended the upper bound on the time possibly elapsed between any two successive token s arrivals at a node ....

[Article contains additional citation context not shown here]

G. Agrawal, B.Chen, W.Zhao, and S.Davari, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," IEEE Trans. on Computers, vol. 43, no. 3, pp. 327--339, 1994.

....its synchronous bandwidth (denoted as H i for node i) which is the maximum time for which the node is allowed to Sijing Zhang, currently with CCSR, University of Cambridge, is a Post Doctorate Fellow supported by Micromuse, Inc. transmit its synchronous messages every time it receives the token [3]. Whenever a node receives the token, it first transmits its synchronous messages, if any, for a time period up to its allocated synchronous bandwidth. The asynchronous messages can then be sent (if any) but only if the token rotated sufficiently fast (since the token s last arrival at the same ....

....all the nodes for asynchronous traffic. We study problems pertaining to guaranteeing a set of synchronous message streams with message deadlines no longer than message periods in FDDI networks. The previous research on protocol timing properties in the context of guaranteeing synchronous traffic [3, 4, 5, 6] implicitly assumes that the worst case happens when every network node has inexhaustible messages (both synchronous and asynchronous) to send such that all available bandwidth of either type (synchronous bandwidth or asynchronous bandwidth or both) can be consumed. Unfortunately, this assumption ....

[Article contains additional citation context not shown here]

G. Agrawal, B.Chen, W.Zhao, and S.Davari, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," IEEE Transactions on Computers, vol. 43, pp. 327--339, March 1994.

....consider a timed token network (say, FDDI) of three nodes, under two different nodes ordering patterns as shown in Figure 1. The considered synchronous message set M with P i = D i (i = 1; 2; 3) and the synchronous bandwidths (H i s) produced by the Normalized Proportional Allocation (NPA) scheme [4] are listed in Table I. Also, for simplicity, assume =0 and TTRT =50. Zhang et al. [3] proposed an algorithm to capture the exact value of R i , which can be used to form an optimal test on schedulability of a synchronous message set in a timed token network of any particular (fixed) ordering. ....

G. Agrawal, B. Chen, W. Zhao and S. Davari, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," IEEE Transactions on Computers, vol. 43, no. 3, pp. 327-339, March 1994.

....then the node may not have enough network access time to transmit a message before its deadline. Therefore, guaranteeing synchronous message deadlines lies on the appropriate allocation of synchronous bandwidths to the nodes. Many synchronous bandwidth allocation (SBA) schemes have been proposed [3, 4, 5, 6, 7, 8, 9, 10, 11] in terms of guaranteeing synchronous message deadlines. In [3] four SBA schemes are proposed and analyzed by Agrawal et al. and a metric called the worst case achievable utilization (WCAU) is adopted as a means to compare and evaluate different schemes. The WCAU of a SBA scheme is defined as the ....

....Therefore, guaranteeing synchronous message deadlines lies on the appropriate allocation of synchronous bandwidths to the nodes. Many synchronous bandwidth allocation (SBA) schemes have been proposed [3, 4, 5, 6, 7, 8, 9, 10, 11] in terms of guaranteeing synchronous message deadlines. In [3], four SBA schemes are proposed and analyzed by Agrawal et al. and a metric called the worst case achievable utilization (WCAU) is adopted as a means to compare and evaluate different schemes. The WCAU of a SBA scheme is defined as the largest utilization (U ) such that the scheme can always ....

[Article contains additional citation context not shown here]

G. Agrawal, B.Chen, W.Zhao, and S.Davari, "Guaranteeing synchronous message deadlines with the timed token protocol," in Proceedings of the 12th IEEE Int'l Conf. on Distributed Computing Systems, June 1992.

....4 experimental evaluation of the performance of the algorithms is discussed in Section 6. Finally, the paper concludes with a summary of the work and conclusions in Section 7. 2. Previous Work Past efforts in real time communication research have focused primarily on static message scheduling [ACZD92, BM91, CAZ92, Fer92, FV90, KZ93, KMZ93, MZ95, MKZ96, Sath93, SLS88a, TBW95]. The fundamental thesis of these efforts is that the communication behavior of the application can be made to be deterministic through extensive a priori knowledge about communication load parameters, message latencies, and precedence relationships. The a priori information is then used to ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing Synchronous Message Deadlines with Timed Token Protocol," Proceedings of The Twelfth IEEE International Conference on Distributed Computing Systems, June 1992.

....Token Cell Cell Cell Cell Cell Channel Figure 1: An architecture for FDDI based mobile networks and a BS is a topic of many papers (e.g. 7, 11, 15, 24] and will not be discussed here. Supporting real time communications in regular (non mobile) FDDI networks has been studied in [1, 2, 8, 33], where the major concern is the amount of FDDI synchronous bandwidth that is needed for a given real time connection. Several schemes have been proposed in attempts to minimize the amount of synchronous bandwidth allocated to a connection. Most technical issues that do not exist in a regular FDDI ....

.... real time channels in FDDI networks is bandwidth allocation: what is the minimum amount of synchronous bandwidth required to support a real time channel (T ; C; d) so that all packets of this channel will be delivered (transmitted) within the delay constraint d This problem has been studied in [1, 2, 8, 33] and several bandwidth allocation schemes have been proposed, all of which generate only approximate, as opposed to optimal, solutions. We will adopt the scheme of [33] which is able to generate optimal solutions for many problem instances. Definition 2 A real time channel (T ; C; d) that has ....

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G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token protocol," in Proc. IEEE International Conference on Distributed Computing Systems, pp. 468--475, June 1992.

....access points. One of the services, real time communications service [7, 12, 19] is of particular importance in today s high speed networks. It can be used to support many applications such as manufacturing systems management, remote monitoring, robotic control, voice and video transmission. In [1, 2, 21], the synchronous transmission capacity of the FDDI networks is shown to be able to support real time communications service. It is desirable to extend this service to mobile users of wireless FDDI networks. One important application of this extension is robotic communications. Communications ....

....last token arrival for the new BS to start transmission without delay constraint violation is t u 1 if M = 1 or t u if M 1. Proof. Let t g be the packet generation starting time and t 0 i (i 0) be the token arrivals to transmit these packets. Bandwidth h s allocated by any scheme, such as in [1, 2, 21], ensures that all packets will be transmitted without delay if t 0 i t g (i 2)TTRT Gamma h s (1) If M = 1, t h = t u . According to Theorem 1, we have t u i 1 t u i 1 t u (i 2)TTRT Gamma h s for any i 0. By Eq. 1) we know data generated after t h will not be delayed if ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token protocol," in Proc. IEEE International Conference on Distributed Computing Systems, pp. 468--475, June 1992.

....excess amount of synchronous capacities to the nodes increases T TR , which may also cause message deadlines to be missed. Therefore, synchronous capacities must be properly allocated to individual nodes. As a consequence, synchronous capacities allocated to the nodes must satisfy two constraints [Agr92, Che92, Mal93]: a protocol constraint and a deadline constraint. The protocol constraint states that the total sum of the allocated synchronous capacities should not be greater that the available portion of T TR , i.e. n i TTRT H 1 t (3.1) Theoretically, the total available time to transmit ....

....to the nodes should be such that the synchronous messages are always guaranteed to be transmitted before their deadlines. A message set can be guaranteed by an allocation scheme once the protocol and the deadline constraints are satisfied. Several allocation schemes have been proposed in [Agr92, Che92, Mal93]. In [Vas94] we can find a first analysis on the message schedulability in Profibus networks. Based on the Timed Token Protocol, these results were later improved and presented in [Vas96] The work here by described is a step forward in the analysis of message schedulability in Profibus networks. ....

Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol", Proceedings of the 12 th IEEE International Conference on Distributed Computing Systems, (June 1992).

....than TTRT. When a token arrives late, a node transmits only synchronous messages. The performance of FDDI depends on protocol parameters such as TTRT and synchronous bandwidths. Thus, previous works focused on the synchronous bandwidth allocation to meet the timing constraints of messages. (Agrawal et al. 1992)(Chen et al. 1992) Agrawal et al. 1993) Chen et al. 1992) proposed optimal allocation schemes. However, depending on the periodic message streams, the network utilization may drop below 33 . 2.3 Overview of FC AL FC AL is a serial data channel that provides a logical bidirectional link ....

Agrawal, G., B. Chen, W. Zhao and S. Davari (1992). Guaranteeing synchronous message deadlines with the timed token protocol.

....guarantees. This protocol is implementable as an enhancement to existing TCP IP protocol suite and will work with off the shelf Ethernet hardware. Earlier work in the area of supporting synchronous or real time traffic on LANs, based on timed token protocols have been analytical in nature ([2], 3] 8] 11] while other implementation efforts have required specialized hardware ( 1] 5] 7] 9] 10] In contrast, the proposed protocol can be fully implemented in software without requiring any modifications to existing Ethernet hardware. Also, RETHER addresses failure and ....

Agrawal, G., Chen, B., Zhao, W., and Davari, S. Guaranteeing synchronous message deadlines with timed token protocol. Proc. of IEEE Intl. Conf. on Distributed Computing Sys., June 1992.

....capabilities of FIP have been widely studied, and [11,12] are just some examples. PROFIBUS adopts a simplified version of the timed token (TT) protocol [13] Despite some differences to the TT protocol used in FDDI or IEEE802.4, for which real time characterisation have been extensively addressed ([14,15] are just some examples) it is still possible to guarantee real time behaviour with PROFIBUS networks [16,17] CAN is itself a priority bus, which adopts a collision avoidance version of the wellknown CSMA CD protocol. In [18,19] the authors show how to guarantee real time behaviour with CAN ....

Agrawal, G., Chen, B., Zhao, W., Davari, S.: "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol", Proceedings of the 12th IEEE International Conference on Distributed Computing Systems, June 1992.

....priority message cycles that a station k is allowed to perform at each token visit. The following low priority message stream notation will be used: k k k nlp Cl Sl , 2) 3.2. Timing Analysis Approach Real time approaches for timed token based protocols, such as for FDDI (Agrawal, et al. 1994; Zheng and Shin, 1995) or for IEEE802.4 Token Bus (Montuschi, et al. 1992) rely on the possibility of allocating specific bandwidth for real time traffic. This means that a minimum amount of time is always available, at each token visit, to transmit real time messages. The above referred ....

Agrawal, G., B. Chen, W. Zhao and S. Davari (1994). Guaranteeing Synchronous Message Deadline with the Timed Token Medium Access Control Protocol. In: IEEE Transactions on Computers, Vol. 43, No. 3, pp. 327-339.

....transmission when holding the token. Figure 3 illustrates this situation. 7 In Profibus, the absence of synchronous bandwidth allocation prevents the use of the traditional Timed Token real time analysis. In fact, real time solutions for networks based on the Timed Token protocol, such as [10,11] (for FDDI networks) or [12] for IEEE 802.4 token bus) rely on the possibility of allocating specific bandwidth for the real time traffic. Master 1 T TR Token Arrival Message Cycle with TTH 0 Token Transmission Message Cycle with TTH 0 Master 2 Master 3 Figure 3 Example of Profibus ....

G. Agrawal, B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadline with the Timed Token Medium Access Control Protocol", IEEE Transactions on Computers, Vol. 43, No. 3, pp. 327-339, March 1994.

....excess amount of synchronous capacities to the nodes increases T TR , which may also cause message deadlines to be missed. Therefore, synchronous capacities must be properly allocated to individual nodes. As a consequence, synchronous capacities allocated to the nodes must satisfy two constraints [15,16]: a protocol constraint and a deadline constraint. The protocol constraint states that the total sum of the allocated synchronous capacities should not be greater that the available portion of T TR , i.e. t = TR n i T H 1 (6) Theoretically, the total available time to transmit ....

Agrawal, G., Chen, B., Zhao, W., Davari, S.: "Guaranteeing Synchronous Message Deadlines with Timed Token Protocol Medium Access Control Protocol", IEEE Transactions on Computers, Vol. 43, No. 3, pp. 327-339, March 1994.

....on FIP [9,10] and on P NET [11,12] Contrarily to other networks [15 16] which are based in the timed token protocol [17] in PROFIBUS it is not possible to define, in each master, its synchronous bandwidth allocation 1 . Thus, it is not possible to use analysis similar to those proposed in [18 19]. In [13] the authors take two different approaches to guarantee real time traffic using PROFIBUS networks. One of the approaches considers a worst case scenario with, at most, one high priority message cycle 2 transmission per token visit. Thus, if there are m high priority messages pending to ....

Agrawal, G., Chen, B., Zhao, W., Davari, S.: "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol". Proceedings of the 12th IEEE International Conference on Distributed Computing Systems, June 1992.

....communicate with each other. This approach is then adopted to the multiprocessing systems. In the area of control we are often coping with problems of decentralized control systems. In such environment a systematic design of a flexible and modular control system and reliable communication support [1] are of major importance. Conventional industrial systems have already been in the process of being replaced by distributed intelligent systems, where intelligence is increasingly being located in the process area of such systems. Nearest to the process is the field area of an industrial system, ....

G.Agrawal, B.Chen, W.Zhao, "Guaranteeing Synchronous Messages Deadlines with the Timed Token Medium Access Control Protocol", IEEE Transactions on Computers, Vol. 43, No. 3, 1994, pp. 327-339.

....Deadline First and Minimum Laxity first on CSMA CD (Carrier Sense Multiple Access with Collision Detection) In [69] Strosnider et al. proposed the use of rate monotonic scheduling (RMS) on an IEEE 802.5 token ring. The use of timed token protocol for real time traffic has been studied in [3, 18]. Point to point networks have also received attention [8, 19, 47, 53, 54, 62] The key advantage of point to point networks is the existence of multiple paths between nodes. However, messages may have to travel multiple hops to reach their destinations. A study of scheduling mixed traffic of ....

....exceed its synchronous capacity. A node is allowed to transmit asynchronous messages only if the time since the last token visit has not exceeded TTRT. The timed token protocol has a nice property that each node is guaranteed v token visits in any time interval of length (v 1)TTRT, for any v 1 [3]. As a result, each node is guaranteed a certain bandwidth for transmitting synchronous messages. Using this property, several different schemes have been proposed in the literature for selecting TTRT and synchronous capacities to guarantee the hard deadlines of a given set of periodic messages ....

[Article contains additional citation context not shown here]

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token protocol," in Proceedings of Distributed Computing Systems, pp. 468--475, June 1992.

....constraints, even for very simple systems. Additional schemes, such as timed tokens in FDDI, must be used to give timing guarantees. Such schemes substantially reduce the maximum utilization of the network resources by real time traffic, e.g. by two thirds for the case of timed tokens in a ring [9]. Time division multiplexing (TDM) on the other hand, avoids resource contention by explicitely laying out the transmission schedule. This obviates the need for expensive collision resolution schemes and results in a high utilization of the network because it allows for high concurrency of access ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token protokol", in Proceedings of the 12th International Conference on Distributed Computing Systems, pp. 468--475, Yokohama, Japan, June 1992.

....procedure used by the SBA manager is left unspecified. In addition, the SMT standard leaves the SBA manager selection scheme totally unspecified. Note that SMT protocols, e.g. neighbor identification, synchronous bandwidth reservation, etc. use asynchronous transmissions. Agrawal et al. [7] present and analyze several synchronous bandwidth allocation schemes. During the bidding for T Opr individual stations would bid a TTRT equal to half their desired CAT (so that the chosen T Opr would satisfy their CAT requirement) FDDI parameter configuration is then straightforward and requires ....

Agrawal et al., "Guaranteeing Synchronous Message Deadlines with the Time Token Protocol," Proc. 12th International Conference on Distributed Computing Systems, Yokohama, Japan, June 1992.

.... large number of applications (such as incorporation of uncompressed video streams in control loops for remote laboratoring) a number of very high speed networking technologies are currently under investigation for their applicability to support hard real time communication, such as ATM [2] FDDI [1], HIPPI [3] We are investigating the applicability of wormhole routed network technologies for this class of applications. As exemplified by recently developed technology, wormhole routed networks are a promising approach for high bandwidth, low latency communication for small and medium sized ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. In IEEE Computer, Vol. 43. No. 3, March 1994.

....of the key issues in tailoring the timed token MAC protocol for real time applications is the synchronous bandwidth allocation (SBA) problem whose objective is to meet both the protocol and deadline constraints. Several non optimal local SBA schemes and an optimal global scheme have been proposed [1 3]. Local SBA schemes use only information available locally to each node, and are thus preferred to global schemes because of their lower network management overhead. Unfortunately, it has been formally proved in [4] that there does not exist any optimal local SBA scheme. Chen et al. 2] proposed ....

....less than TTRT. Many researchers studied the access time bounds and other timing properties of the timed token protocol. In particular, Johnson et al. 5, 6] proved that the average token cycle time is bounded by TTRT, and the maximum token cycle time is bounded by 2 Theta TTRT. Agrawal et al. [1, 2] extended Johnson s result and proved that the time elapsed between k consecutive token s visits to a node is bounded by k Theta TTRT. They also formulated a synchronous bandwidth allocation (SBA) problem and attempted to calculate the synchronous bandwidth H i that should be allocated to node ....

[Article contains additional citation context not shown here]

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," IEEE Trans. on Computers, vol. 43, pp. 327--350, March 1994.

....bounded access time of 2 Delta TTRT to the transmission medium. This is because the maximum token rotation time has been shown to be 2 Delta TTRT [12,22] Agrawal et al. generalized this result to provide an upper bound on the time between any v consecutive visits of the token to a given station [2,3]. Let t i (l) denote the time when the token makes its l th visit to station i. Theorem 1: From [2,3] For any l 0, v 0, and any station i (1 i n) t i (l v Gamma 1) Gamma t i (l) v Delta TTRT Gamma H i : 4:1) Suppose that at time t 0 , station i has a real time message with a ....

....time has been shown to be 2 Delta TTRT [12,22] Agrawal et al. generalized this result to provide an upper bound on the time between any v consecutive visits of the token to a given station [2,3] Let t i (l) denote the time when the token makes its l th visit to station i. Theorem 1: From [2,3]] For any l 0, v 0, and any station i (1 i n) t i (l v Gamma 1) Gamma t i (l) v Delta TTRT Gamma H i : 4:1) Suppose that at time t 0 , station i has a real time message with a relative deadline d and a transmission time C queued for transmission. In order to guarantee that the ....

[Article contains additional citation context not shown here]

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," IEEE Transactions on Computers, vol. 43, no. 3, pp. 327--339, March 1994.

.... of utilization based tests are known for centralized systems (e.g. 69 and 100 utilization bounds for periodic tasks on a single server using rate monotonic and earliest deadlinefirst scheduling, respectively[14] or distributed systems (such as 33# for synchronous traffic over FDDI networks [23]) In this paper, we adopt utilization based tests in providing differentiated services in static priority scheduling networks. Flow population insensitive delay analysis has been recently studied in [3] for the case of aggregate scheduling. Lower bounds on the worst case delay are derived. These ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol, IEEE Proceedings of

....mechanism defines a utilization bound below which all the workload using the resource is guaranteed to meet its deadline. UBAC was first proposed in [22] for preemptive scheduling of periodic tasks on a single server. Then the concept was applied to FDDI networks for scheduling synchronous traffic [1]. Most recently, the idea was used in general multi node networks in the diffserv setting for providing deterministic guarantees [30] In these studies, although the idea of UBAC remains the same, the approaches taken are different. It is much more difficult to derive the utilization bounds in the ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol, IEEE International Conference on Distributed Computing Systems, 1992, pp.468-475.

....scheduling of periodic tasks. A variety of the utilization levels for different settings have been found, e.g. 69 and 100 for periodic tasks on a single server using rate monotonic and earliest deadline first scheduling, respectively [14] or 33 for synchronous traffic over FDDI networks [22]. In this paper, we adopt this approach in providing absolute differentiated services in static priority scheduling networks. C. Priority Assignment This paper focuses on priority assignment in static priority scheduling networks for real time communication applications, within Diffserv domain. ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol, IEEE International Conference on Distributed Computing Systems, 1992, pp.468-475.

.... of utilization based tests are known for centralized systems (e.g. 69 and 100 utilization bounds for periodic tasks on a single server using rate monotonic and earliest deadlinefirst scheduling, respectively[14] or distributed systems (such as 33 for synchronous traffic over FDDI networks [23]) In this paper, we adopt utilization based tests in providing differentiated services in static priority scheduling networks. Flow population insensitive delay analysis has been recently studied in [3] for the case of aggregate scheduling. Lower bounds on the worst case delay are derived. These ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol, IEEE Proceedings of ICDCS, 1992. APPENDIX A: PROOF OF THEOREM 2 Theorem 2: The aggregated traffic of the group of flows

....schedulability testing and admission control mechanisms. All these techniques de ne a utilization level below which all the workload using the resource is guaran1 teed to meet its deadline. This utilization level is sometimes called the worst case achievable utilization (WCAU) for that resource [3]. The WCAU can then be compared against the resource utilization during schedulability testing at design time or during admission control at run time to determine whether the workload can be guaranteed to meet its deadlines. A variety of WCAU s for di erent settings have been found, e.g. 69 and ....

.... A variety of WCAU s for di erent settings have been found, e.g. 69 and 100 for preemptive scheduling of periodic tasks on a single server using rate monotonic and earliest deadline rst scheduling, respectively [2] or 33 bandwidth utilization for scheduling synchronous trac over FDDI networks [3]. Unfortunately, previous work on utilization based methods to provide end to end delay guarantees in distributed systems has been limited. WCAU s have been derived for single servers only, or for some shared servers (like token rings) and can therefore be used only indirectly for systems with ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, \Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol," IEEE International Conference on Distributed Computing Systems, 1992, pp.468-475.

....provide scalable and robust schedulability testing and admission control mechanisms. These methods define a utilization level below which all the workload using the resource is guaranteed to meet its deadline. This utilization level is sometimes called the worst case achievable utilization (WCAU)[3]. The WCAU can then be compared against the resource utilization during schedulability testing or during admission control to determine whether the workload can be guaranteed to meet its deadlines. A variety of WCAU s for different settings have been found, e.g. 69 and 100 for preemptive ....

.... of WCAU s for different settings have been found, e.g. 69 and 100 for preemptive scheduling of periodic tasks on a single server using rate monotonic and earliest deadline first scheduling, respectively [2] or 33 bandwidth utilization for scheduling synchronous traffic over FDDI networks [3]. Unfortunately, previous work on utilization based meth ods to provide end to end delay guarantees in distributed systems has been limited. WCAU s have been derived for single servers only, or for some shared servers (like token rings) Most previous studies on utilization based methods also ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol," Proc. of ICDCS, 1992.

....allocation scheme (PA) can asymptotically approach 0 . Two other schemes, the equal partition allocation scheme (EPA) and the normalized proportional allocation scheme (NPA) fare better, with the latter achieving a WCAU of 33 if the value of TTRT is selected as recommended in the FDDI standard [3]. However, this SBA scheme is a global one, in that system wide information such as message periods and lengths on the nodes as well as the total utilization is required. As a result, global SBA schemes are not very suitable for dynamic environments since changes in the message stream at a ....

G. Agrawal, B. Chen, W. Zhao, and S. Davari. Guaranteeing synchronous message deadlines with the timed token medium access control protocol. IEEE Trans. Comput., 43:327--339, 1994.

....the proposal of FDDI M. To guarantee the transmission of synchronous messages before their deadlines, it is important to select the appropriate values for the parameters TTRT and H i . Various schemes for allocating synchronous bandwidth of each station have been proposed in the literature. In [1], Agrawal et al. proposed and analyzed a number of SBA scheme. H i s results showed that the WCAU of two local SBA schemes (the full length allocation scheme (FLA) and the proportional allocation scheme (PA) can asymptotically approach 0 . Two other schemes, the equal partition allocation scheme ....

....bandwidth to transmit asynchronous packets, a scheme known as FDDI M [11] Note this scheme does not attempt to improve the ability of FDDI M in supporting synchronous traffic. In a previous paper [4] we have derived analytically the WCAU values for three of the earliest SBA schemes proposed in [1]. Some simulation work on the ability of FDDI M to support video traffic has also appeared previously [14] but the results are based only on the FLA scheme. 3. Classification of the SBA Schemes Traditionally, SBA schemes are classified into local or global schemes according to whether they need ....

[Article contains additional citation context not shown here]

G. Agrawal, B. Chen, and W. Zhao. Guaranteeing synchronous message deadlines with the timed token medium access protocol. Proc. 12th IEEE International Conf. on Distributed Computing Systems 1992, 1992.

....Sha [22] However, no analysis of such a scheme has been reported so far. The timed token protocol was first proposed by Grow in [6] This protocol has the important property of bounded access time for the nodes on the ring. The real time performance of this protocol has been recently studied in [2, 3, 4, 9]. It was shown that with a proper choice of protocol parameters, this protocol can guarantee a synchronous traffic of up to 33 in the worst case. However, the issue of average case performance of this protocol has not been addressed so far. Our objective here is to derive precise criteria for ....

....protocols to schedule real time messages over the entire population of message sets. For a meaningful comparison between two protocols, we need an aggregate measure to quantify the overall performance of a protocol. Recent research in real time systems has focussed on utilization based metrics. In [2, 3], Minimum Breakdown Utilization 1 has been used to quantify the performance of a protocol. Minimum Breakdown Utilization of a protocol is defined as the threshold utilization below which all the real time messages are always guaranteed. The minimum breakdown utilization indicates the worst ....

[Article contains additional citation context not shown here]

G. Agrawal, B. Chen, W. Zhao, and S. Davari, "Guaranteeing Synchronous Message Deadlines with Timed Token Protocol", IEEE Conf. on Distributed Computing Systems, June 1992.

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G. Agrawal, B. Chen, and W. Zhao, "Guaranteeing synchronous message deadlines with the timed token medium access control protocol," in Proc. 12th IEEE Int. Conf. Distributed Computing Systems, June 1992, pp. 468--475.

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Agr92b. Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol", Proceedings of the 12th IEEE International Conference on Distributed Computing Systems (June 1992).

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Agr92a. Agrawal, G., B. Chen, W. Zhao and S. Davari , "Guaranteeing Synchronous Message Deadlines with the Timed Token Medium Access Control Protocol", Technical Report, Computer Science Department, Texas A&M University (Feb. 1992).

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Agr94. Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Medium Access Control Protocol", IEEE Transactions on Computers 43(3), pp. 327-339 (March 1994).

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Agr92b. Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Medium Access Control Protocol", Technical Report 92-006, Computer Science Department, Texas A&M University (April 1992).

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Agr92a. Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol", Proceedings of the 12th IEEE International Conference on Distributed Computing Systems (June 1992).

No context found.

Agrawal, G., Chen, B., Zhao, W. and Davari, S. 1992. Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. Proceedings of the 12

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Agrawal, G., Chen, B., Zhao, W. and Davari, S. 1992. Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. Proceedings of the 12

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G. Agrawal, B. Chen, W. Zhao, and S. Davari. Guaranteeing synchronous message deadlines with the timed token medium access control protocol. IEEE Transactions on Computers, 43(3):327--339, Mar. 1994.

No context found.

G. Agrawal, B. Chen and Wei Zhao, Guaranteeing Synchronous Message Deadline with Timed Token Medium Access Control Protocol, IEEE Trans on Computer, 43(3), pp 327-339, 1994.

No context found.

Gopal Agrawal, Baio Chen, Wei Zhao, and Sadegh Davari. Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. In The 12 th International Conference on Distributed Computing Systems, pages 468--475, IEEE Computer Society Press, June 1992.

No context found.

Gopal Agrawal, Baio Chen, Wei Zhao, and Sadegh Davari. Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol. In The 12 th International Conference on Distributed Computing Systems, pages 468--475, IEEE Computer Society Press, June 1992.

No context found.

Agr92b. Agrawal, G., B. Chen, W. Zhao and S. Davari, "Guaranteeing Synchronous Message Deadlines with the Timed Token Protocol", Proceedings of the 12th IEEE International Conference on Distributed Computing Systems (June 1992).

No context found.

Agr92a. Agrawal, G., B. Chen, W. Zhao and S. Davari , "Guaranteeing Synchronous Message Deadlines with the Timed Token Medium Access Control Protocol", Technical Report, Computer Science Department, Texas A&M University (Feb. 1992).

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