A Resilient Packet Ring is a ring-based network protocol standardized by IEEE 802.1. It is adequate to be used by service providers in MANs or WANs.
In a Resilient Packet Ring topology the access to the medium method applied is the buffer insertion ring. Every station on the ring has a buffer that is called a transit queue, frames passing by the station that are not destined to it may be temporarily stored in this buffer. A station may only start sending a frame if the transit queue is empty and there is no transit frame. If a transit frame arrives at a station while the station is already transmitting a frame the transit frame must wait in queue till the other frame is completely transmitted.
A spatial re-use occurs when a frame is removed from the ring by the receiver RPR station and the path's bandwidth that leads back to the source is available to be used by another sender.
A a resilient packet ring network work based on a three-level class priority scheme. The aim is to treat traffic with different requirements and priorities accordingly.
Class A is a low-latency low-jitter class, class B has predictable latency and jitter, and class C is treated as best effort data delivery. No frame is are discarded in case of congestion, every frame will eventually reach its destination. be a best effort transport class.
Class A traffic is subdivided into classes A0 and A1 and class B is divided into BCIR (committed information rate) and B-EIR (excess-Information rate)
Service to class A0, A1, and B-CIR traffic have their required bandwidth preallocated. For class A0 the preallocated BW is reserved and can only be used by the station that reserved it. If it is not used it is wasted. BW for A1 and B-CIR is reclaimable and if not used may be used by best effort traffic (classes B-EIR and C).
In a Resilient Packet Ring topology the access to the medium method applied is the buffer insertion ring. Every station on the ring has a buffer that is called a transit queue, frames passing by the station that are not destined to it may be temporarily stored in this buffer. A station may only start sending a frame if the transit queue is empty and there is no transit frame. If a transit frame arrives at a station while the station is already transmitting a frame the transit frame must wait in queue till the other frame is completely transmitted.
A spatial re-use occurs when a frame is removed from the ring by the receiver RPR station and the path's bandwidth that leads back to the source is available to be used by another sender.
A a resilient packet ring network work based on a three-level class priority scheme. The aim is to treat traffic with different requirements and priorities accordingly.
Class A is a low-latency low-jitter class, class B has predictable latency and jitter, and class C is treated as best effort data delivery. No frame is are discarded in case of congestion, every frame will eventually reach its destination. be a best effort transport class.
Class A traffic is subdivided into classes A0 and A1 and class B is divided into BCIR (committed information rate) and B-EIR (excess-Information rate)
Service to class A0, A1, and B-CIR traffic have their required bandwidth preallocated. For class A0 the preallocated BW is reserved and can only be used by the station that reserved it. If it is not used it is wasted. BW for A1 and B-CIR is reclaimable and if not used may be used by best effort traffic (classes B-EIR and C).
Davik, F.; Yilmaz, M.; Gjessing, S. & Uzun, N. (2004), 'IEEE 802.17 resilient packet ring tutorial', Communications Magazine, IEEE 42(3), 112—118.
Tsang, D., 'Resilient Packet Ring', Lecture 8 Dr. Danny Tsang Department of Electrical & Electronic Engineering Hong Kong University of Science and Technology.
S. Spadaro, J. Sole-Pareta, D. Careglio, K. Wajda, A. Szymanski,“Positioning of the RPR standard in contemporary operator environments,”Network, IEEE Volume 18, Issue 2, Mar-Apr 2004 Page(s):35 –40
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