RSVP Signaling Research Articles

IPv6-Based Dynamic Quality of Service Control Strategy for Wireless Network

On the basis of the architecture for fast handover of hierarchical IPv6, a coordinated call admission control mechanism was presented, providing an end-to-end RSVP context transfer for real-time applications to overcome t he weakness of the context transfer protocol which cannot meet the need of end-to-end QoS mechanisms because the contexts were only transferred between the previous and new access routers. The mechanism decreased the delay caused by re-initiate QoS signaling from scratch to reestablish QoS forwarding process, and minimized the handover service disruption. The signaling overhead and handover latencies could be reduced by adopting t he fast handover for hierarchical IPv6 architecture. The approach was compared with the re-initiating RSVP signaling to reestablish QoS states using network simulator ns2. The numerical results showed that the scheme has the less latency and packet loss than that of the re-initiating approach.

Supporting vertical handover between universal mobile telecommunications system and wireless LAN for real-time services

The provisioning of the seamless handovers for real-time services in-between UMTS/ WLAN loose-interworking by the network-layer technologies has been studied. Issues are how to execute such a vertical handover in a fast and efficient manner as well as how to achieve it in a viable way. To resolve such issues, a novel scheme called 'designated crossover point' (DCP) within the existing IP end-to-end quality of service (QoS) architecture has been proposed. The DCP is an agent at the edge router in the customer's premise to join the old RSVP signalling path and new RSVP signalling path. With the DCP in place, the vertical handover can be greatly accelerated. Besides, by enabling the DCP to handover to the edge router in the customer's network currently visited by the mobile, lower charging cost can be achieved. Finally, there is no modification required for the devices in the provider's network and thus the viability is much improved. It is then end up with a topology for resource management in IP backbone for UMTS/WLAN loose-interworking to support the idea of DCP. To determine when to perform the rerouting to remove the possible derouting caused by DCPs, use of an adaptive rule has been suggested. Simulation results show in general that the adaptive rule is effective.

Performance evaluation of RSVP extensions for a guaranteed delivery scenario

In some guaranteed data delivery scenarios, servers can quickly and carefully allocate the available bandwidth among the requests of the users to reduce rejections. This is particularly important when reservations are higher than minimum required delivery rate (semi-elastic reservations). As an example, when semi-elastic reservations utilize all the available server bandwidth and a new flow reservation arrives, it is useful to reallocate current reservations to accept the new one. The RSVP protocol is receiver oriented and it is in charge of setting up these reservations. However, in some cases, to reallocate bandwidth in a receiver oriented way could delay the required sender reservation adjustments. This paper presents a new extension of the RSVP signaling messages that allows the server to adjust and modify these reservations. The performance evaluation of the extended and the native RSVP signaling protocols when used to manage the access bandwidth of a semi elastic flows server shows the benefits of the extensions. In particular, the use of resource reservation is reduced because of a more efficient bandwidth usage. In addition, the blocking probability is also reduced because of a more flexible bandwidth reallocation situation. The authors believe that this procedure is an intermediate step to improve the lack of flexibility that RSVP presents.

A New Technique to Expedite RSVP Path Re-establishments in 802.11 Wireless LANs

This paper proposes a novel scheme that exploits the Inter Access Point Protocol (IAPP), currently standardized by IEEE, in order to expedite the RSVP path re-establishment that takes place after a handover from one WLAN Access Point (AP) to another. The prime characteristic of this scheme is that a WLAN AP serves as an RSVP proxy and starts RSVP signaling on behalf of the Mobile Node much earlier compared with the standard RSVP operation in a WLAN. Therefore, a considerable handover latency reduction can be achieved, which can be as high as 20%. To evaluate the performance and the benefits of the proposed scheme, we display and discuss a series of simulation results. In addition, we present in detail its operation and we discuss the RSVP objects that should be transferred across APs through IAPP. In this context, we also explain the structure of the proposed RSVP Information Elements. Our simulation results show considerable performance improvement, especially in heavy traffic load conditions. Note that the proposed scheme can work with the standard RSVP protocol, as well as with partial path re-establishment methods and can be combined with advanced admission control algorithms in the AP.

Reliable RSVP path reservation for multimedia communications under an IP micromobility scenario

We focus on how quality of service (QoS) guarantees can be provided for RSVP flows during handoff events in an IP micromobility network. For this purpose, RSVP message delays and signaling overheads should be minimized, and handoff service disruption should also be minimized. By rerouting the RSVP branch path at a crossover router at every handoff event, and establishing the new RSVP path between the CR and new BS in advance while the existing reservation path is maintained, ongoing RSVP flows can be kept with the guaranteed QoS. We propose the seamless switching of an RSVP branch path for soft handoff, and also show that this scheme could provide QoS guarantee with simulation and examples.

A QoS service for IP video applications on demand over DTM

The Differentiated Services model (DiffServ) provides a great flexibility in defining a variety of services through PHBs ( Per Hop Behaviors ) and traffic conditioners. It fits in well with the Integrated Services model (IntServ), jointly offering features such as: QoS signaling; admission control; channel management; assignment of resources (buffer and bandwidth); sorter configuration; and establishment of traffic agreements. With this integration you can have a scalable, flexible, and dynamic QoS environment in networks of the Internet core.This article describes and analyzes the DGF ( DTM Guaranteed Forwarding ) service that guarantees a minimum rate of retransmission of packets, based on RSVP signaling and traffic agreements (SLA), as well as losses close to the error rate of the physical medium, which are ideal features for video applications on demand.When this service is provided, the aforementioned QoS models are integrated with the transport and switching solution called DTM ( Dynamic Synchronous Transfer Mode ), a fast circuit switching technology. DTM is simple, cost-effective, provides QoS features, and is naturally dynamic in supplying bandwidth as well as flexible in fitting in with other IETF QoS models.Thus in the proposed architecture, IPoDQoS ( IP over DTM QoS ), we make use of the dynamism of network protocols and we offer managed VBR traffic in the IP layer (i.e.: DGF service) not originally offered in DTM technology.

Design and implementation of a QoS capable switch-router

An important challenge for the future growth of the Internet is to design routers that can forward the exponentially increasing volume of traffic, and at the same time provide the service differentiation needed by new applications. In this paper, we describe the architecture, implementation, and initial experiences with a system designed to meet this challenge. This system, which we call a QoS capable Switch-Router (QSR), combines the salient features of switching and routing technologies to provide high throughput and support the different classes of service being defined by the IETF. It consists of a core (ATM) switch fabric connecting intelligent adapters, each capable of both routing and switching packets. A control engine is responsible for routing, RSVP signaling, and resource management. We have built a prototype network of 3 systems connected to several UNIX hosts, and have conducted preliminary performance measurements on this network.