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101
Decoupling QoS Control from Core Routers: A Novel Bandwidth Broker Architecture for Scalable Support of Guaranteed Services
, 2000
"... We present a novel bandwidth broker architecture for scalable support of guaranteed services that decouples the QoS control plane from the packet forwarding plane. More specifically, under this architecture, core routers do not maintain any QoS reservation states, whether per-flow or aggregate. Inst ..."
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Cited by 77 (8 self)
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We present a novel bandwidth broker architecture for scalable support of guaranteed services that decouples the QoS control plane from the packet forwarding plane. More specifically, under this architecture, core routers do not maintain any QoS reservation states, whether per-flow or aggregate. Instead, the QoS reservation states are stored at and managed by a bandwidth broker. There are several advantages of such a bandwidth broker architecture. Among others, it avoids the problem of inconsistent QoS states faced by the conventional hop-by-hop, distributed admission control approach. Furthermore, it allows us to design efficient admission control algorithms without incurring any overhead at core routers. The proposed bandwidth broker architecture is designed based on a core stateless virtual time reference system developed in [16]. This virtual time reference system provides a unifying framework to characterize, in terms of their abilities to support delay guarantees, both the per-hop behaviors of core routers and the end-to-end properties of their concatenation. In this paper we focus on the design of efficient admission control algorithms under the proposed bandwidth broker architecture. We consider both per-flow end-to-end guaranteed delay services and class-based guaranteed delay services with ow aggregation. Using our bandwidth broker architecture, we demonstrate how admission control can be done on an entire path basis, instead of on a "hop-by-hop" basis. Such an approach may significantly reduce the complexity of the admission control algorithms. In designing class-based admission control algorithms, we investigate the problem of ow aggregation in providing guaranteed delay services, and devise a new apparatus to effectively circumvent this problem. We conduct extensiv...
Internet telephony: Architecture and protocols – an IETF perspective
- Computer Networks and ISDN Systems
, 1999
"... Internet telephony offers the opportunity to design a global multimedia communications system that may eventually replace the existing telephony infrastructure. We describe the upper-layer protocol components that are specific to Internet telephony services: the Real-Time Transport Protocol (RTP) to ..."
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Cited by 71 (20 self)
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Internet telephony offers the opportunity to design a global multimedia communications system that may eventually replace the existing telephony infrastructure. We describe the upper-layer protocol components that are specific to Internet telephony services: the Real-Time Transport Protocol (RTP) to carry voice and video data, and the Session Initiation Protocol (SIP) for signaling. We also mention some complementary protocols, including the Real Time Streaming Protocol (RTSP) for control of streaming media, and the Wide Area Service Discovery Protocol (WASRV) for location of telephony gateways. 1
Comparison of Adaptive Internet Multimedia Applications
"... The current Internet does not offer any quality of service guarantees or support to Internet multimedia applications such as Internet telephony and video-conferencing, due to the besteffort nature of the Internet. Their performance may be adversely affected by network congestion. Also, since these a ..."
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Cited by 65 (11 self)
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The current Internet does not offer any quality of service guarantees or support to Internet multimedia applications such as Internet telephony and video-conferencing, due to the besteffort nature of the Internet. Their performance may be adversely affected by network congestion. Also, since these applications commonly employ the UDP transport protocol, which lacks congestion control mechanisms, they may severely overload the network and starve other applications. We present an overview of recent research efforts in developing adaptive delivery models for Internet multimedia applications, which dynamically adjust the transmission rate according to network conditions. We classify the approaches used to develop adaptive delivery models with brief descriptions of representative research work. We then evaluate the approaches based on important design issues and performance criteria, such as the scalability of the control mechanism, responsiveness in detecting and reacting to congestion, and ability to accommodate receiver heterogeniety. Some conclusions are developed regarding the suitability of particular design choices under various conditions.
Theories and Models for Internet Quality of Service
, 2002
"... We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated serv ..."
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Cited by 64 (1 self)
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We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also briefly discussed. We then turn our attention to statistical performance guarantees, and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review recent proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support.
An integrated resource negotiation, pricing, and QoS adaptation framework for multimedia applications
- IEEE Journal on Selected Areas in Communications
, 2000
"... Abstract—We study a dynamic, usage- and congestion-dependent pricing system in conjunction with price-sensitive user adaptation of network usage. We first present a resource negotiation and pricing (RNAP) protocol and architecture to enable users to select and dynamically renegotiate network service ..."
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Cited by 44 (7 self)
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Abstract—We study a dynamic, usage- and congestion-dependent pricing system in conjunction with price-sensitive user adaptation of network usage. We first present a resource negotiation and pricing (RNAP) protocol and architecture to enable users to select and dynamically renegotiate network services. We develop mechanisms within the RNAP architecture for the network to dynamically formulate prices and communicate pricing and charging information to the users. We then outline a general pricing strategy in this context. We discuss candidate algorithms by which applications (singly, or as part of a multiapplication system) can adapt their rate and QoS requests, based on the user-perceived value of a given combination of transmission parameters. Finally, we present experimental results to show that usage- and congestion-dependent pricing can effectively reduce the blocking probability, and allow bandwidth to be shared fairly among applications, depending on the elasticity of their respective bandwidth requirements. Index Terms—Adaptive systems, communication system economics, communication system signaling, communication system traffic, computer network management, multimedia communication, resource management. I.
RNAP: A resource negotiation and pricing protocol
- in International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV’99), Basking
, 1999
"... Network delivery services providing “better-than-best-effort ” service over the Internet are being studied, and are particularly necessary for multimedia applications. The selection and use of a specific delivery service involves negotiation between the user and the network; they agree upon specific ..."
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Cited by 35 (9 self)
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Network delivery services providing “better-than-best-effort ” service over the Internet are being studied, and are particularly necessary for multimedia applications. The selection and use of a specific delivery service involves negotiation between the user and the network; they agree upon specifications such as the type of service user packets will receive, the constraints the user traffic must adhere to, and the price to be charged for the service. In this paper, we describe a protocol through which the user and the network (or two network domains) can negotiate network services. We refer to the protocol as a Resource Negotiation and Pricing protocol (RNAP). Through RNAP, the network service provider communicates availability of services and delivers price quotations and charging information to the user, and the user requests or re-negotiates services with desired specifications for one or more flows. RNAP protocol mechanisms are flexible enough to support multiple delivery service models, and allow dynamic re-negotiation of services during a session. Two different network architectures are defined to support RNAP, a centralized architecture with a Network Resource Negotiator (NRN) administering each network domain, and a distributed architecture without any centralized controlling entity. Mechanisms are proposed for local price and charge computation, formulation of end-to-end prices and charges across multiple domains, and communication of this information through RNAP messages. Results of a prototype implementation are briefly described. 1
Staged Refresh Timers for RSVP
- in Proc of IEEE Global Internet
, 1997
"... Abstract—The current resource Reservation Protocol (RSVP) design has no reliability mechanism for the delivery of control messages. Instead, RSVP relies on periodic refresh between routers to maintain reservation states. This approach has several problems in a congested network. End systems send PAT ..."
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Cited by 35 (9 self)
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Abstract—The current resource Reservation Protocol (RSVP) design has no reliability mechanism for the delivery of control messages. Instead, RSVP relies on periodic refresh between routers to maintain reservation states. This approach has several problems in a congested network. End systems send PATH and RESV messages to set up RSVP connections. If the first PATH or RESV message from an end system is accidentally lost in the network, a copy of the message will not be retransmitted until the end of a refresh interval, causing a delay of 30 seconds or more until a reservation is established. If a congested link causes a tear-down message (PATHTEAR or RESVTEAR) to be dropped, the corresponding reservation will not be removed from the routers until the RSVP cleanup timer expires. We present an RSVP enhancement called staged refresh timers to support fast and reliable message delivery that ensures hop-by-hop delivery of control messages without violating the soft-state design. The enhancement is backwards-compatible and can be easily added to current implementations. The new approach can speed up the delivery of trigger messages while reducing the amount of refresh messages. The approach is also applicable to other soft-state protocols. Keywords—RSVP; soft state; reliability; signaling. I.
Intra-Domain QoS Routing in IP Networks: A Feasibility and Cost/Benefit Analysis
- IEEE Network
, 1999
"... Constraint-based routing gradually becomes an essential enabling mechanism for a variety of emerging network services such as virtual private networking and QoS support. A number of recent works have recognized its significance and investigated many aspects of the operation of constraint based ro ..."
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Cited by 30 (2 self)
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Constraint-based routing gradually becomes an essential enabling mechanism for a variety of emerging network services such as virtual private networking and QoS support. A number of recent works have recognized its significance and investigated many aspects of the operation of constraint based routing and in particular its variant that is concerned with determining paths for requests with specific QoS requirements, known as QoS routing. In this work we build on previous results on the cost of QoS routing and investigate the performance/cost trade-offs involved in the operation of a representative QoS routing architecture, elaborate on the constituents of this cost, and identify the main methods for containing the cost that QoS routing incurs on routers. Our results show that the cost of QoS routing is not excessive and that there indeed exist operational configurations, that can achieve reasonable performance gains with only a minimal increase in processing cost when compared...
Internet Telephony Gateway Location
- Proc. Conf. Computer Comm. (IEEE Infocom), IEEE CS Press, Los Alamitos, Calif
, 1998
"... Although the Internet was designed to handle non-real time data traffic, it is being used increasingly to carry voice and video. One important class of contributors to this growth are Internet telephones. Critical to more widespread use of Internet telephony is smooth interoperability with the exist ..."
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Cited by 26 (5 self)
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Although the Internet was designed to handle non-real time data traffic, it is being used increasingly to carry voice and video. One important class of contributors to this growth are Internet telephones. Critical to more widespread use of Internet telephony is smooth interoperability with the existing telephone network. This interoperability comes through the use of Internet Telephony Gateway’s (ITG’s) which perform protocol translation between an IP network and the Public Switched Telephone Network (PSTN). In order for an IP host to call a user on the PSTN, the IP host must know the IP address of an appropriate gateway. We consider here the problem of finding these gateways. An analysis of a number of protocol architectures is presented, including hierarchical databases, multicast advertisement, routing protocols, and centralized databases. We propose a new protocol architecture, called Brokered Multicast Advertisements (BMA) which serves as a lightweight, scalable mechanism for locating ITG’s. The BMA architecure is general, and can be applied to location of any service across a wide area network. 1
A hardware implementation of a signaling protocol
- Proc. of Opticomm 2002, July 29-Aug
"... Signaling protocols in switches are primarily implemented in software for two important reasons. First, signaling protocols are quite complex with many messages, parameters and procedures. Second, signaling protocols are updated often requiring a certain amount of flexibility for upgrading field imp ..."
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Cited by 19 (9 self)
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Signaling protocols in switches are primarily implemented in software for two important reasons. First, signaling protocols are quite complex with many messages, parameters and procedures. Second, signaling protocols are updated often requiring a certain amount of flexibility for upgrading field implementations. While these are two good reasons for implementing signaling protocols in software, there is an associated performance penalty. Even with state-of-the-art processors, software implementations of signaling protocol are rarely capable of handling over 1000 calls/sec. Correspondingly, call setup delays per switch are in the order of milliseconds. Towards improving performance we implemented a signaling protocol in reconfigurable FPGA hardware. Our implementation demonstrates the feasibility of 100x-1000x speedup vis-à-vis software implementations on state-of-the-art processors. The impact of this work can be quite far-reaching by allowing connection-oriented networks to support a variety of new applications, even those with short call holding times.
