rpr rings vs rpr over sonet rings

RPR Rings vs RPR over SONET Rings

S. [email protected]

Outline

n Objectives

n Metro Traffic

n Metro Network Architectures

n Possible Network Solutions

n Study of one ring

n Assumptions

n Results

n Conclusions

Objectives

n Understand the value of RPR ring solutions with competing solutions

n What is the value of running RPR on its own versus over SONET

n Assume RPR Ring solutions will have similar price/performance as today's enterprise Ethernet switches

n Assume latest SONET price/performance in the market

Traffic Demand

0

5

10

15

20

25

1999 2000 2001 2002 2003

DS

-3 e

quiv

alen

ts fr

om a

typi

cal s

ite

PoS/EthernetATM

FR/PPP

P/L

Voicen Voice - CAGR 6%

n Private Line - majority of access traffic - CAGR 20%

n IP/Ethernet - CAGR - 200%, most access becomes via Ethernet

n ATM - small fraction but grows at 100%

n FR - CAGR 35%

Metro Network Architecture

n Small diameter access rings with larger links for inter-CO

n Most/all traffic on access rings travels to CO

n Metro Core links may have access ADMs but less likely

Metro CoreCentral Offices

Metro Core Links

Access Rings

SONET with RPR

n Assume newer high density SONET with cross-connect capability

n RPR based rings run over SONET as un-protected traffic

n RPR traffic uses SONET framing and run as a concatenated signal

n SONET accesses traditional TDM traffic from DS-1 to OC-48

n In study assumed OC-48 SONET UPSR rings with an overlaid RPR ring with OC-n (n = multiple of 3)

10/100/1000BaseT

DS-1/DS-3

OC-3OC-12OC-48

ADM

RPR and SONET in Parallel

ATM

10/100 BaseTGigabit Ethernet

TDM:ADM

Gigabit Ethernet Links

SONET UPSR

n New SONET and RPR rings are built as parallel networks on different fibers

n RPR rings are 1 Gb/s rings

n SONET rings are OC-48 rings

n Assume fiber is fairly cheap

Modeling of a Single Ring

n Peaked Traffic reflecting some large buildings

n Average of 8-10 nodes per ring

n All Traffic hubbed to CO node

7.5 5 4 3.5 3.5 32.5

1.5

UPSR – Traffic hubbed to CO nodeCO - node

No of DS-3 equivalentsdropped at customer locations

Assumptions

n Key Prices Usedl SONET Equipment

u Chassis - 60X (Can handle 2 OC-48 Rings) - takes 1/4 of rack

u OC-48 - 30X

u 10/100 Per Port Cost - 2X

u Gigabit Ethernet Per Port Cost - 10X

l RPR Based Switch

u Chassis - 30X (can handle 2 Gig E rings) - takes 1/8 of rack

u 10/100 Per Port Cost - X

u Gigabit Ethernet Per Port Cost - 7.5X

l RPR based switches at most 60% of SONET switch costs

Other Assumptions

n Real-Estate Costs - 4X/month/rack

n Power Costs - 1.5X/month/rack

n Fiber Costs - 2.5X/fiber/mile (one-time)

n Interest Rate - 9%

Results - NPV to 2001

-

0.20

0.40

0.60

0.80

1.00

1.20

RPR on SONET RPR Rings and SONETRings

Co

st U

nit

s FiberPowerReal-EstateCapital

n Fairly even mix of Ethernet and non-Ethernet traffic (40:60)

n Integrated Solution is about 20% lower cost

n One Unit = 5000X


-

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80


Co

st U

nit


n Ethernet to non-Ethernet (60:40)

n Fairly even cost solutions


n Ethernet to non-Ethernet (75:25)

n Parallel network solution better due to better cost/port and chassis costs

-

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00


Co

st U

nit


Key Conclusions

n The results be even more tilted towards RPR on SONET when total network management costs are included as managing two separate networks would be more than one network

n When fiber costs are high, it would favor the single network solution of RPR on SONET even more as passive DWDM costs are about high perlambda on each end.

n With active DWDM the penalty of having more lambdas would be even higher

n The parallel networks solution does appear to be cheaper with 75% or more of Ethernet traffic

n RPR on SONET is likely a more efficient solution for a large majority of types of traffic cases

rpr rings vs rpr over sonet rings

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