Scalable Research Education Networks Dr Brian Smith Senior
Scalable Research & Education Networks Dr. Brian Smith, Senior Optical Systems Designer
Content § Introduction. § Review of Requirements for Research and Education Regional Optical Networks. § Comparing Strategies for Regional Optical Networks. § Towards seamless overlay of 10 Gbps and 40 Gbps traffic. Confidential
Introduction § Regional Optical Networks for Research and Education are being built at an increasing rate § Acquisition of dark fiber – lit up as private networks § Some University focused – some joint education/government initiatives. § Large Scale Research Applications are driving the demand for dedicated bandwidth § Real time image sharing between collaborating institutions § Very Large Baseline Interferometry § Distributed supercomputer simulations § Interactive Video Requires a network that can respond quickly to the demands of the Research Community Confidential
What features would be required in such a network ? § Dynamic Provisioning § Fully reconfigurable wavelength node § Simple migration from ring to mesh networking. § Ability to switch light-paths using Central/Distributed Management workstation(s). § Single wavelength granularity add and drop. § Seamless switching between DWDM and CWDM providing cost effective multi-grid networks. § Bit rate and protocol transparency – universal interface to higher layers. § Traffic grooming down to ‘STS-1’ level for ultimate flexibility but with GFP for protocol transparency. = Optimum network configuration matched to actual demand. Confidential
Other Features ? § Simple and Cost-Effective § Transport platform that integrates WDM transmission, wavelength switching and SDH/SONET grooming. § Central or distributed management of all network elements. § Layer 1 performance monitoring at every node – fault isolation. § Auto discovery of nodes, cards and optical interfaces § Interface directly to existing Gig. E /10 Gig. E routers/switches (carry 10 Gig. E LAN PHY natively without expensive WAN PHY/SONET encapsulation). § Carry any service (Ethernet, SONET, SAN) at wire speed from Fast Ethernet to 10 Gig. E and beyond. Reduced cost and complexity = Rapid response to new Research Initiatives Confidential
§ Scalability § Add wavelengths ‘in-service’ with no impact on existing traffic. § Add wavelengths with no adjustments to network provisioning (amplifiers etc). § Seamless overlay of wavelengths carrying traffic up to 2. 5 G, 10 G and 40 G over the same fiber. § Allow addition of on-grid alien wavelengths. § Make full use of industry standard technologies such as SFP/XFP to reduce cost and complexity of sparing. All of these features ARE available. . . Confidential
Meriton Product Family Metro Access Metro Core & Regional Link Extension Products 3300 OSU 7200 OADX 1450 OFA Line 1100 DCMs § CWDM & DWDM § Transparent & SRM - Ethernet & SANs § § § § § Fully passive with low insertion loss - STMx, OCx § Ring, star, & linear § 10 Gbps supported § Seamless interworking with 7200 OADX Multi-transport platform Wavelength switching (128 l) STS 1 grooming (320 G) CWDM, DWDM & ROADM transmission § Transparent & GFP interfaces § Mesh, ring, star § Scaleable Pre/post/line EDFA Raman Amplifiers Intelligent controls Transient suppression § 1510 nm OSC § Up to 600 km links without regen Fully Managed via the 8600 NMS & 8300 EMS Confidential
OADM vs OADX Network Issues Confidential
Typical OADM Serial Filter Design Complicates network planning/engineering. - adding a filter affects the whole network. Dedicated WDM Transponders Prevents interconnection of CWDM to DWDM. Results in stranded wavelengths around the ring. - all wavelengths in a band are expected to be dropped at the same site Transponder. Based Architecture Lambda Add/Drop Fixed by Band Adding wavelengths requires service outage. - filter insertion, re-cabling, and power re-balancing. Lack of wavelength switching. - limits networking to point-to-point or ring only. Can only switch on hard failures eg. fiber cuts. - Cannot switch on data error rate degradation. Protection Switching Limited to LOS. Cannot monitor layer 1 (protocol level) error rate. - Cannot detect data errors and degradation. Performance Monitoring Limited to Optical Level. Truck rolls required to add new service type. - different trib card required per protocol type. Protocol-specific client-side cards. Limited Maintenance & Diagnostic Support. Difficult to isolate faults - no electrical loop-backs. Confidential
7200 OADX – Unique Product Architecture Simplified network design. - Link based design Full 3 R Regeneration Wavelength Translation Electronic ROADM Architecture Full CWDM to DWDM connectivity. Non-blocking add/drop of wavelengths. (any wavelength in to any wavelength out). No stranded wavelengths. Wavelength Switching at the Electrical Level Hitless maintenance switches. - of protected lightpaths or cross-connects. Supports up to 16 WDM network interfaces. - allow support of multiple point-to-point, ring, and mesh networks concurrently. Monitoring and detection of layer 1 data errors and degradation. (SONET/SDH, GIGE, FICON, ESCON, Fiber Channel) Performance Monitoring at the Optical and Electrical Level. Protection switching on data error threshold. - protection on loss of signal or error threshold detect Same trib card supports multiple service types. - simplified sparing, pay as you grow upgrade - SFPs Universal client-side cards. Supports Multiple Loopbacks at the Electrical Level. Simplified network troubleshooting. Confidential
OADM vs OADX Multi-Degree Support Meriton 7200 OADX Typical OADM West East 2 WDM Network Interfaces Maximum East 16 WDM Network Interfaces Single point-to-point, or single ring network only Multiple point-to-point, multiple ring, multiple mesh network configurations concurrently. Shared network – Not dedicated Confidential
OADM vs OADX Multi-WDM Interface Support Meriton 7200 OADX Typical OADM CWDM West DWDM CWDM DWDM West East CWDM DWDM East CWDM DWDM DWDM OR CWDM DWDM network interfaces must match. AND AND DWDM CWDM Any combination of WDM network interfaces. Confidential
OADM vs OADX High Error Rate Protection Switching DWDM CWDM DWDM Layer 1 performance monitoring detects high error rate and initiates protection switch. Fiber Kink Highlayer error 1 rate initiated protection switching is detect NOT supported OADX performance monitoring is used to high errorby rates OADMs. - no level 1 performance to detect data errors and automatically trigger protectionmonitoring switching. Confidential
OADM vs OADX Adding Wavelengths Confidential
Typical OADM capacity upgrade § OADM solutions address fiber exhaust needs but introduce difficult operational and engineering constraints § Serial Architecture Filter Design (Cascaded & Banded) § Result in Stranded Bandwidth § Serious Scaling Pains w/Re-engineering Required Output w/No Balancing 2 1 OEO 4 3 OEO Confidential Optical Power DWDM NE Maximum Power L 2 L 3 L 4 L Filter Loss = L
7200 OADX capacity upgrade Output w/No Balancing Optical Power DWDM band 1 DWDM Mux 1 DWDM • No power balancing or equalization required when adding wavelengths. • No re-engineering required simply plug in card / SFP / XFP and your up and running Confidential
Capacity Upgrade – Line Amplifiers OADM Re-provision optical amplifiers to maintain link-budget 7200 OADX 1450 OFA amplifiers use gain control – More Gain – No Pain! Confidential
OADM vs OADX Adding New Nodes Confidential
OADM vs OADX – Network Changes Need to add an additional service, including “Bridge” Break Bring Establish the the new connections fibre. existing Meriton Noservice connection: service node to the outages! into new on-the-fly: hitlessly service, “Roll” the existing back to its Existing operational network and service inserting aservice new POP/node here. using swing into equipment. the existing Provision capacity, network. to the and point, new No activate path, service click, with aup new no and original route. running service outages! light path. outage. in seconds. 7200 Bridge OADX and bridge-and-roll is NOT supported providesby hitless OADMs. maintenance operations. - all switch operations result in service disruptions Confidential
OADM vs OADX Multi-Protocols Trib Card Support Meriton 7200 OADX Typical OADM SONET OC-12 SONET OC-48 SDH STM-1 SDH STM-4 Gig. E • Single Tributary Interface Card. • Multiple Protocols Require Multiple Cards • Any port – Any Protocol. • More Costly and Complex Upgrades • Universal Pluggable SFP/XFP Interface • More expensive Sparing • Cost Effective Sparing Confidential
Meriton 7200 OADX vs OADM Functionality Meriton 7200 OADX Typical OADM Switching Integrated? Yes No Ring Support? Simplified Engineering Complex Engineering Mesh Support? Yes No Mix CWDM & DWDM? Yes No Wavelength Translation? Yes No Layer 1 Performance Monitoring? Yes No Hitless Maintenance Yes No; requires services outages Scalability Yes, cost-effective Difficult and expensive Confidential
Overlaying 10 G and 40 G traffic on existing networks Confidential
Link Engineering- Challenges 2. 5 G DWDM OFA 10 G OTR DCM Mux Need to understand Dispersion tolerancedispersion and PMD tolerance are much more of an issue to overlay 10 G when overlaying 40 G traffic 40 G Lets have a quick look at these issues. . . Confidential
Dispersion Tolerance § The dispersion experienced over any km of fiber segment lies within a range defined by the manufacturer. Dispersion (ps/nmkm) Compensation (ps/nm) § Similarly, the amount of compensation delivered by a typical DCM is only accurately known within a range. Wavelength (nm) Confidential Wavelength (nm)
Dispersion Tolerance (cont. . ) § Taking a 6 span x 80 km link with each span compensated 100%, the actual net dispersion can lie between – 500 and +500 ps/nm ! § So how would this large range in net dispersion affect the eye closure penalty for 2. 5, 10 and 40 G traffic ? Confidential
6 x 80 kmx 26 d. B - 32 needs ADCM + enhanced FEC 40 G needs FEC 10 G 2. 5 G Confidential
Polarization Mode Dispersion § Using 6 x 80 kmx 26 d. B with 6 EDFA and 6 DCM, the calculated average DGD (assuming fiber is post 1995) = 2. 5 ps § The PMD tolerance (and expected outage) for various data rates is: Rate pmd tolerance system outages/yr 2. 5 G 30 ps insignificant pmd outages/yr 10 G 7. 6 ps insignificant pmd outages/yr 40 G(NRZ) 1. 9 ps ~ 22 minutes/year uncompensated 40 G(RZ) 2. 7 ps ~0. 5 seconds/year uncompensated 40 G scenarios improved using enhanced FEC and/or PMD compensation. Confidential
10 G + 40 G overlay on existing traffic § With an appropriate adaptive DCM at the receiver and enhanced FEC, 40 G traffic can be transmitted over a system designed to support 2. 5 and 10 G traffic. § With PMD compensation and/or FEC, a 40 G(NRZ) system is capable of reaching ~ 500 km with no significant outages resulting from PMD. § A 40 G(RZ) system with FEC is capable of reaching ~ 700 km with no significant outages resulting from PMD Confidential
Summary § Reviewed some of the requirements for Research and Education Regional Optical Networks. § Compared OADM vs OADX strategies for Regional Optical Networking. § Analyzed the impact of Chromatic Dispersion and PMD tolerance for migration to 40 Gbps traffic over existing networks. Confidential
Thank You Dr. Brian Smith brian. smith@meriton. com Confidential
- Slides: 30