When simplicity becomes complex On the road to a scalable and dynamic - PowerPoint PPT Presentation

When simplicity becomes complex On the road to a scalable and dynamic SURFnet7 network Terena Network Architects Workshop, Copenhagen Wouter Huisman

What do we want from a network? • Scalable • Flexible • Cost efficient • Endusers service requirements • Bottomline is keep it simple

SURFnet6 network Hamburg Münster Aachen 3 Geneva (CERN)

Collapsed I P core Border Routers Located in Ams1 and Ams2 SURFnet AS1 1 0 3 Core Routers Customer SURFnet – SNE masters BGP in de praktijk

Transport layer

Inter Domain NSI BoD in SURFnet6 Application NSI User NOC engineer

What to optimize of SURFnet6? And make SURFnet7 simple…

SURFnet7 : Scalable netw ork I nstitute I nstitute Routed I P ✔ 2008 ( Layer 3 ) Application Application Application Application Application Application Next Generation Ethernet Service Service ( Layer 2 ) ✔ 2010 Bandw idth Bandw idth Optisch Transport ( Layer 0 / 1 ) 8

Concepts in the SURFnet7 tender • Single technology end-2-end transport • Remove as many OEO as possible • Be ready for 40G and 100G • Improve the BoD solution • Selected Ciena CES solution – 5410, 3930, 5150 – Based on PBB-TE

Tiered Network Architecture

Tiered Network Architecture

Tiered Network Architecture

Tiered Network Architecture

Tiered Network Architecture

Tunable XFP & OTN XFP 5410 ‐ CES CPL – DWDM OADM • No transponder shelves required • Tunable DWDM XFP used Transponder • Save on power, footprint, OAM • ~25% of the links require G.709

Scalability issue • Uptake lightpath services was significant • Technology limitation • Bandwidth claimed for 100%, even though not all used. • Single service per port

Statistical Multiplexing EIR CIR a a b a,b,c b a c b c c 17

One or more services on a single port • Single Service Port (SSP) - One service, one port • Multi Service Port (MSP) - Multiple network services, one port - Efficient use of interfaces 10 Gbit/s SURFinternet SURF-lightpath SURF-lightpath OnDemand lightpath Free MSP Interface 2 Gbit/s 1 Gbit/s 2 Gbit/s 3 Gbit/s 2 Gbit/s 18

BoD in SURFnet7 NOC engineer User Application Inter Domain NSI NSI GUI API Identity SURFnet7 BoD Provider MTOSI GUI SURFnet7 NMS Group Provider 19 19

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Can we manage elephant flows? • Unpredictability of the dynamic nature of BoD • BoD tend to generate large flows (> 1Gb/s) • Can we rely on the NMS?

BW enforcement for tunnels and services • Layered structure of tunnels and services • Each tunnel has a bandwidth profile • Services are added to tunnels as long as tunnel can accommodate Link capacity Tunnel profile Service BW

Tunnel CIR: 2 node network Future lightpaths A B Existing lightpaths Consider: • 10G Link between A and B • Filled with single tunnel and consuming 50% of CIR bandwidth • 5G SLP is to be reserved for new install • Tunnel profile is changed to claim 100% CIR bandwidth In mean time a DLP is reserved claim 1G bandwidth on the existing tunnel, and • consumes the bandwidth of the SLP service • End result: SLP can not claim its bandwidth on this link SLP: static lightpath DLP dynamic lightpath

Solution • DLP can only be transported across DLP tunnels • Claim Bandwidth in advance – Create dummy tunnels with required CIR for new services – Or increase the CIR bandwidth of existing SLP tunnels

2 elevator dilemma • Assume 2 elevators, both with capacity for exact 10 people

2 elevator dilemma • Assume 2 elevators, both with capacity for exact 10 people Drop at least 1 person and a guitar

LAG problem • Consider Lightpath flows of 6 Gb/s and of 5 Gb/s – A CES will autonomous decide, which LAG member to use – A LAG of 2 x 10G should be sufficient – But you have 50% chance on packet drop • Problem with LAGs with flows > 10% physical link speed

Solutions to the LAG issue • Use higher line rate instead of LAGs – Use 100G • Use LAGs, but be conscious not to put high bandwidth flows on a LAG as you are loosing control

NMS implements Strict & Loose CAC flag Strict CAC LAG • LAG with 1 member • Can accommodate any services Loose CAC LAG • LAG with possibly more link members • Accommodates Lightpaths upto 1Gb/s And IP

Conclusions • SURFnet7 has some clear optimizations – End-2-end single service layer for IP and lightpath – Tunable XFP – BoD uses the NMS DB and path computation – Statistical multiplexing – Multi Service Ports • Complications to secure BW guarantee – Large single data flows – Unpredictable network planning

wouter.huisman[at]surfnet.nl W www.surfnet.nl +31 30 2 305 305 Creative Commons “Attribution” license: http://creativecommons.org/licenses/by/3.0/