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A Method to Determine the Average IP Packet Delay in an APSON Network with non-negligible Path Setup Times

IP.com Disclosure Number: IPCOM000127686D
Original Publication Date: 2005-Oct-10
Included in the Prior Art Database: 2005-Oct-10
Document File: 6 page(s) / 216K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

The optimization of the design of Adaptive Part Switched Optical Networks (APSON) in the manner that a certain delay requirement is met depicts a technical problem. Until now the only method of resolution of this problem is described by a method which determines the Average IP Packet Delay in an APSON. Because this method is aimed to APSON’s with fast switching equipment (in the range of ns or ps) the path setup times could be neglected. But in case of switching times in the range of µs or ms, which is more desirable, the path setup times are non-negligible. In the following a solution is proposed which extends the concept of the mentioned method in case of non-negligible path setup times. In addition the model is also extended to the case of multimode optical fibers comprising several wavelengths. In particular, new expressions for the average throughput, for the average burst arrival rate, for the average link load and for the average IP packet delay are given. In addition a new concept in APSON called the effective bandwidth is introduced and calculated by means of the analytical model. The effective bandwidth is the link capacity that is left after removing the path setup times during which no information can be sent. Therefore, it is a measure of the link capacity which can really be used to transfer information. As described in the mentioned method the delay formula is used in order to calculate the average IP packet delay in any APSO network.

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A Method to Determine the Average IP Packet Delay in an APSON Network with non-negligible Path Setup Times

Idea: Miguel de Vega Rodrigo, DE-Munich

The optimization of the design of Adaptive Part Switched Optical Networks (APSON) in the manner that a certain delay requirement is met depicts a technical problem. Until now the only method of resolution of this problem is described by a method which determines the Average IP Packet Delay in an APSON. Because this method is aimed to APSON's with fast switching equipment (in the range of ns or ps) the path setup times could be neglected. But in case of switching times in the range of µs or ms, which is more desirable, the path setup times are non-negligible.

In the following a solution is proposed which extends the concept of the mentioned method in case of non-negligible path setup times. In addition the model is also extended to the case of multimode optical fibers comprising several wavelengths. In particular, new expressions for the average throughput, for the average burst arrival rate, for the average link load and for the average IP packet delay are given. In addition a new concept in APSON called the effective bandwidth is introduced and calculated by means of the analytical model.

The effective bandwidth is the link capacity that is left after removing the path setup times during which no information can be sent. Therefore, it is a measure of the link capacity which can really be used to transfer information. As described in the mentioned method the delay formula is used in order to calculate the average IP packet delay in any APSO network.

Method to calculate the average link utilization in an APSO network:

Figure 1 shows the analytical model of a 2WR-OBS (Wavelength Routed-Optical Burst Switching) network, which is used. A total number of NS sources send information through a common link (optical fiber) which capacity C is equal to Nλ wavelengths * Cλ capacity of each wavelength (C = Nλ*Cλ). The average IP packet arrival rate of each source is represented by λIPi , and the average IP packet size by µ. Each burst from each one of the NS sources is carried out by one of the Nλ available wavelengths. The mapping between wavelengths and bursts is done according to a wavelength assignment or wavelength scheduling algorithm, which selects the wavelength on which a burst will be sent according to some performance criteria. It is assumed that the load of the NS traffic sources is equally distributed among the Nλ wavelengths of capacity Cλ. In the following a single wavelength (and its capacity Cλ) of the optical fiber and its capacity C is analyzed.

The Effective Wavelength Capacity:

In APSON's the average path or connection duration is equal to 1 / λλ, where λλ is the burst arrival rate per wavelength (shown in figure 2). The expression 1/ λλ represents also the average burst inter-arrival time, which is the time elapsed between the arrivals of two consecutive burst...