Analysis of multi-path routing

Proceedings of INFOCOM '97, 1997

In high-speed networks it is desirable to interleave routing and resource (such as bandwidth) reservation. The PNNI standard for private ATM networks is a recent example for an algorithm that does this using a sequential crank-back mechanism. In this work, we suggest to do resource r eservation along several routes in parallel. We present an analytical model that demonstrates that when there a r e several routes to the destination it pays to attempt reservation along more t h a n a single route. Following this analytic observation, we present a family of algorithms that route and reserve resources along parallel subroutes. The algorithms of the family represent di erent trade-o s between the speed and the quality of the established r oute. The presented algorithms are simulated against several legacy algorithm, including PNNI crank-back, and exhibit higher network utilization and faster connection set-up time.

Computer Networks, 2008

A key problem in networks that support advance reservations is the routing and time scheduling of connections with flexible starting time. In this paper we present a multicost routing and scheduling algorithm for selecting the path to be followed by such a connection and the time the data should start so as to minimize the reception time at the destination, or some other QoS requirement. The utilization profiles of the network links, the link propagation delays, and the parameters of the connection to be scheduled form the inputs to the algorithm. We initially present a scheme of non-polynomial complexity to compute a set of so-called non-dominated candidate paths, from which the optimal path can be found. By appropriately pruning the set of candidate paths using path pseudo-domination relationships, we also find multicost routing and scheduling algorithms of polynomial complexity. We examine the performance of the algorithms in the special case of an Optical Burst Switched network. Our results indicate that the proposed polynomial time algorithms have performance that it is very close to that of the optimal algorithm.

IEEE Wireless Communications, 2002

2000

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.

Performance Evaluation, 1996

One of the main features of ATM (Asynchronous Transfer Mode) is that the transmission rate can be adjusted according to the degree of network congestion. FRP (Fast Reservation Protocol) is a recently proposed protocol which can utilize this unique feature of ATM technology in such a way that the amount of bandwidth a source requests is reduced if an attempt to reserve bandwidth is rejected by the network. A rationale behind this is that the rejection of the bandwidth request indicates network congestion. Therefore, requests for smaller amounts of bandwidth after reservation failures enable sources to share network resources efficiently. To evaluate burst (a protocol data unit of FRP) level performance of FRP, this paper provides an approximate analysis of FRP-based ATM networks with arbitrary topologies. Its mathematical model is considered as a loss network with retrials, which allows that the amount of bandwidth requested by retrial bursts is reduced and that bursts may have alternative routes. Through numerical results, the appropriate bandwidth reservation method and routing strategy are studied in depth. PI1 SOl66-5316(96)00013-Z ' J J J J '

Computer networks, 2003

IEEE Communications Magazine, 2002

1997

Absrrucr-This paper addresses the issue of QoS path management in IP networks. We describe a proposal aimed at allowing management through the RSVP 131 protocol of paths selected by a QoS routing algorithm such as those of I1 1,161. The goals of the proposal are to allow efficient management of such QoS paths with a minimal impact to the RSVP protocol and the existing routing infrastructure. Basic features of the approach include leveraging of RSVP soft state mechanisms, and simple extensions to enable soft pinning (sticking) of paths selected by the QoS routing algorithm. In addition, the proposal addresses the issue of preventing the formation of data path loops, and of avoiding potential race conditions.

Path computation elements (PCE's) are used to com- pute end-to-end paths across multiple areas. Multiple PCE's may be dedicated to each area to provide su cient path computation capacity and redundancy. An open problem is which PCE should be chosen to send the path computation request to, that may be a non trivial problem if PCE's have uneven processing capacities. This paper presents a product form queueing model to estimate the latencies in path computation while accounting for the arrival rate of path computation requests. The model is used to find the PCE selection policy to minimize the overall expected latencies in path computation. The model is validated against two simulation benchmarks obtained using OPNET, i.e., a network of queues and the multi protocol label switching with tra c engineering (MPLS- TE) network running the PCE communication protocol (PCEP). The study shows that the use of product form yields approxima- tions that are up to 15% at practical o...