Resilient Packet Ring Network

8/3/2019 Resilient Packet Ring Network

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RESILIENT PACKET RING NETWORK(RPR)


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The nature of the public network has changed. Demand for

Internet Protocol(IP)data is growing at a compound annual rate ofbetween 100% and 800%1,while voice demand remains stable.

Over the last 10 years, as data traffic has grown both in

importance and volume , technologies such as frame relay , ATM ,

and point-to-point protocol (PPP) have been developed to force fit

data onto the circuit network

More recently , Gigabit Ethernet has been adopted by many

network service providers.

Gig has shortcomings when applied in carrier networks were

recognized and for these problems, a technology called ResilientPacket Ring Technology were developed.


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Resilient Packet Ring Technology (RPR).

Resilient Packet Ring (RPR) is an emerging networkarchitecture and technology designed to meet the

requirements of a packet-based metropolitan area

network(MAN).

Neither SONET nor Ethernet is ideal for handling

multimedia traffic on a ring network

Resilient Packet Ring (RPR) is a network topology being

developed as a new standard for fiber optic rings

It works in point to point ,ring or mesh networks.

Uses MAC layer tech.(Standardized as IEEE 802.17)


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Resilience proactive span protection automatically avoids failedspans within 50 ms.

Services support for latency/jitter sensitive traffic such as voiceand video.support for committed information rate (CIR)

services.

Efficiency spatial reuse:Unlike SONET,bandwidth is consumed onlybetween the source and destination nodes.packets are

removed at their destination ,leaving this bandwidth

available to downstream nodes on the ring.

Scalable supports topologies of more than 100 nodes per ring.

RPRs Key features


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RPR uses a dual counter rotating fiber ring topology

Both rings inner and outer are used to transport working traffic

between nodes .By utilizing both fibers RPR utilizes the total available ring

bandwidth, fibers are used to carry control messages

Control message flow in the opposite direction of the traffic that

they represent.using bandwidth-control messages It has ability to differentiate

between low-and high-priority packets nodes have the ability

to transmit high-priority packets before those of low priority

RPR Operation


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RPR nodes also have a transit path

It has a transit buffer capable of holding multiple packetsNodes with smaller transit buffers

use bandwidth-control messages

RPR Media Access Control(MAC).

one ofthe basic building blocks of RPR.

responsible for providing access to the fiber media.

can receive,transit and transmit packets.


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Receive

Decision

TX BW

ControlTransit Path

To Host

Topology

From Host

Protection

TX

BW

To Host From Host

From West

Fiber

To

West

Fiber

To

East

Fiber

MAC Block Diagram


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Receive Decision

Every station has 48 bit MAC address.

MAC will receive any packets with a matching destination address MAC receive both unicast and multi cast packets

there are also control packets that are meant for the neighboring

node

these packets do not need a destination or source address.

Transit PathNodes with non matching destination address are allowed to

circulate

RPR packets are only inspected for a matching address and header

errors

Transmit and Bandwidth Controls

RPR MAC can transmit both high-and-low priority packets

for low-priority packets bandwidth algorithm controls whether a

node is within its negotiated bandwidth allotment bandwidth-control

algorithm


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Protection

RPR has the ability to protect the network from single

span failures.Wrapping

Nodes neighbouring the failed span diverts the packet by

wrapping traffic around to the other fiber

span

Topology Discovery:

RPR has a topology discovery mechanism

Physical Layer

RPR packet can be transported over both SONET and

Ethernet physical layersSONET physical layer offers

robust error and performance monitoring.

when using SONET physical layer,RPR can be carried over dark

fiber.


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Comparison between Gigabit Ethernet and RPR

GIGABIT ETHERNET RPR

Enterprise-class equipment Carrier-class equipment

Provides Data service only Data, circuit or video service

Works in Point-to-point or

mesh topology(No Rings)

Point-to-point,linear,ring,or

mesh topology

Protection in 50 seconds Protection in 50

milliseconds or less

simple management complex management

Has Limited scalability Contains 254 nodes per

ring,multiple rings


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SONET RPR

Has Manual topology Confg Auto-topology config.

16 nodes per ring 254 nodes ring

management bandwidth is

fixed

Time division multiplexing

Management bandwidth

used as needed

Statistical multiplexing

Has Manual provisioning of

bandwidth and routes

Manual or dynamic

provisioning

No service class awareness Differentiated services in

eight classes

Fixed direction traffic routing Least-cost traffic routing


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Technical aspects of RPR

Multicast

packet can be transmitted around the ring and

can be received by multiple nodes.

Mesh topologies requires multicast packets to be replicated

over all possible paths, wasting bandwidth.Spatial Reuse

RPR has the ability to switch traffic over

multiple spans of the rings simultaneously

Bandwidth on a particular span between ring nodes is utilized async.Fairness

most important features in carrier-class networks

RPR protocol can guarantee fairness

across the metropolitan network.


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Quality of Service

is required in order to let a carrier effectively

charge for the services it provides. ATM promised to deliver multiple services due to its rich QoS set.

several parameters govern the characteristics of a delivered service

Service availability,

delay,

delay variation and

RPR Market Development

ISP Network

RPR solutions are helping ISPs todeliver reliable internet services (such and IP and video) and

address the growing bandwidth service

requirements for the next generation intra-point of presence (POP)

exchange point,

and server frame/storage applications.


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Regional Metro Network

. RPR regional metro solutions are available for transport

over dark fiber, over wavelength division multiplexing (WDM), and

over SONET

cable, and

enterprise/campus MANsMetro Access Networks

provide direct Ethernet connectivity for

multi-tenant/multidwelling customers and

edge programmability.


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Provides End-to-end networking through a standard,

Maximum utilization of the fiber bandwidth

Faster deployment of services.

Ease of provisioning and management of the ring.


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Main objectives of RPR

enable a true alternative to SONET

providing carriers with resiliency

fast protection and restoration and performance monitoring

designed to combine SONET strengths of

high availability

reliability

and TDM services support,

superior bandwidth utilization and

high service granularity characteristics.

Conclusion


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RPR is

reliable,

efficient

promoted and standardized by industry leaders-

as well as by innovative startup companies,

positioned to take a major role in deployment

of next generation carrier-class networks.

Resilient Packet Ring Network

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