RESILIENT PACKET RING NETWORK(RPR)

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• RESILIENT PACKET RING NETWORK(RPR)

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INTRODUCION

• The nature of the public network has changed.
  Demand for Internet Protocol(IP)data is growing
  at a compound annual rate of between 100 and
  8001,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 Resilient Packet Ring
  Technology were developed.

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• Resilient Packet Ring Technology (RPR).
• Resilient Packet Ring (RPR) is an emerging
  network architecture 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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RPRs Key features
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RPR Operation
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 a RPR node can be
dynamically negotiate for bandwidth with the
other nodes on the ring. 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  
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• RPR nodes also have a transit path
• It has a transit buffer capable of holding
  multiple packets
• Nodes with smaller transit buffers
• use bandwidth-control messages
• RPR Media Access Control(MAC).
• one of the basic building blocks of RPR.
• responsible for providing access to the fiber
  media.
• can receive,transit and transmit packets.

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From West Fiber
To West Fiber
To East Fiber
TX BW Control
Receive Decision
Transit Path
Topology
TX BW
Protection
From Host
To Host
To Host
From Host
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 Path
• nodes with non matching dstn 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 layers SONET
physical layer offers robust error and
performance monitoring. when using SONET
physical layer,RPR can be carried over dark fiber.
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RPR packets can be encapsulated within the
synchronous payload envelope(SPE) RPR Mac
frame
Flow ID
C
E
Header Error Check(2)
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• Destination Address
• is the MAC address of the ring to which the frame
  
• is being transmitted
• address can also be a broadcast address.
• Source Address
• is the MAC address of the ring node
• from which the frame is being transmitted.
• Payload Type
• this two byte field tells the system what type
  of the payload
• follows the RPR field.
• For example MPEG,ATM or Ethernet.
• Class of service(CoS)
• this three byte CoS field allows the
  identification of
• up to eight Classes of services, including
• Expedited Forwarding(EF),
• six levels of Assured Forwarding(AFI through
  AF6), and Best Effort(BE).

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Extension(E) Bit indicates that there is an
extension to the RPR header allows for fields
that may be added in the future. Flow
ID(optional) allows the simple manual or
automatic setup of connection oriented
services including Time Division
Multiplexed(TDM) 20 BIT field. Time to
live(TTL) the one bit TTL field is included
to allow the RPR ring topology Header Error
Check(HEC) provides a way to test the integrity
of the header, allowing for persistent delivery
of frames Cyclic Redundancy Check(CRC) this 4
byte CRC works differently in RPR than it does
for standard Ethernet .
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Comparison between Gigabit Ethernet and RPR
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Comparison between SONET/SDH and RPT
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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 to
• deliver 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 MANs
• Metro Access Networks
• provide direct Ethernet connectivity for
• multi-tenant/multidwelling customers and
• edge programmability.

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Benefits of RPR
        Packets-optimized, Layer-1 independent
protocol that allows transport,
switching and routing functions in a single
platform.       Provides  Differentiated data
services, with advanced QoS
mechanisms.         Provides Point-to-point and
multipoint services.
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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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Conclusion

• 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.

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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.

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References

• Data Networks by Dimitri Bertsekas and Robert
  Gallagar.
• Computer Networks by Andrew .S. and Taneabaum.
• Computer Network A system approach by
  Larry.L.Petterson and Bruces David.