A Local switched Network, for example a Local switched Ethernet Network, comprises a number of transmitting and receiving local clients or nodes that are connected to a common switch via segments dedicated to each of the local clients. The purpose of the switch within the Local switched Network is that it should, roughly speaking, act as a bridge interconnecting all of the local clients within the Local switched Network as well as connecting the local clients with the outside world, that is, with transmitting and receiving clients located outside the Local switched Network.
Usually the only devices present on a dedicated segment in the Local switched Network is the switch and the corresponding local client, therefore every frame transmission performed within the Local switched Network is picked up by the switch on the segment dedicated to the receiver and relayed to an intended receiver along the receiving clients dedicated segment. Since the only devices present on a receiving clients dedicated segment are the switch and the receiving client the frames will reach the intended recipient after the relay. With this Network design it is possible to have a large number of conversations occurring simultaneously.
Typically a Local switched Network comprises a large number of local clients with dedicated segments; it is not unusual that a Local switched Network comprises many hundreds of local clients. Due to the fact that all transmitted frames within the network are picked up and relayed by the switch, the strains on the switch will be substantial when there is intensive traffic over the Local switched Network. During such intensive periods there will inevitably pile up frames that are yet to be relayed by the switch. Some of these frames may be buffered in the switch for subsequent relaying but since the buffer capacity of the switch is limited, the frames that are arriving when the buffer queue of the switch is full will be dropped. After being dropped the frames will be lost and will have to be retransmitted from the local client. This will in turn cause substantial traffic delays.
The problem is also present during so called traffic bursts within the Local switched Network, that is, when a large amount of frames are sent to the switch during a relatively short time period. Even if a particular switch buffer is dimensioned to be able to store a large amount of frames there are circumstances when traffic bursts will lead to a saturated buffer capacity and a loss of frames due to frame dropping.
Some measures have been taken to mitigate the problems of frame dropping in a Network due to traffic bursts. In the article, “Delaying Transmission in Data Communication Network to Improve Transport-Layer Performance”, Cai, Wolf and Gong, IEEE Journal on selected areas in communication, Vol 29, No. 5, May 2011, a queue based pacing algorithm is presented. This algorithm aims to decrease the burstiness of Network traffic by delaying information packets based on the length of the local packet buffer.
In the article “High-resolution Timer-based Packet Pacing Mechanism on the Linux Operating system”, Takano et al, IEICE Transactions on Communications; ISSN 0916-8516; VOL. 2011; NO. 8; page 2199.2207, there is disclosed a high-resolution timer based packet pacing mechanism for reducing the traffic burstiness in a Network.
However, none of the proposed pacing methods solves the problem of dropped frames completely. It is therefore still a need within the art to find new and efficient ways to obtain a robust scheme for frame transmission within a Local switched Network.