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

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

Dec 16, 2022 37 likes •352 views

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

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When simplicity becomes complex

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

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What do we want from a network?

  • Scalable
  • Flexible
  • Cost efficient
  • Endusers service requirements
  • Bottomline is keep it simple
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SURFnet6 network

3

Münster Aachen Hamburg Geneva (CERN)

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Collapsed I P core

SURFnet – SNE masters BGP in de praktijk

SURFnet AS1 1 0 3

Customer

Border Routers Core Routers

Located in Ams1 and Ams2

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Transport layer

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BoD in SURFnet6

NOC engineer Application User NSI NSI Inter Domain

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What to optimize of SURFnet6?

And make SURFnet7 simple…

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I nstitute

Optisch Transport ( Layer 0 / 1 ) Next Generation Ethernet ( Layer 2 ) Routed I P ( Layer 3 )

I nstitute Bandw idth Service Bandw idth Service

Application Application Application Application Application Application

✔2010 ✔2008

SURFnet7 : Scalable netw ork

8

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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

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Tiered Network Architecture

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Tiered Network Architecture

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Tiered Network Architecture

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Tiered Network Architecture

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Tiered Network Architecture

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Tunable XFP & OTN XFP

CPL – DWDM OADM 5410 ‐ CES Transponder

  • No transponder shelves required
  • Tunable DWDM XFP used
  • Save on power, footprint, OAM
  • ~25% of the links require G.709
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Scalability issue

  • Uptake lightpath services

was significant

  • Technology limitation
  • Bandwidth claimed for

100%, even though not all used.

  • Single service per port
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a b c

17

a b c

a b c a,b,c

EIR CIR

Statistical Multiplexing

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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

18 SURFinternet SURF-lightpath SURF-lightpath OnDemand lightpath Free

2 Gbit/s 1 Gbit/s 2 Gbit/s 3 Gbit/s 2 Gbit/s 10 Gbit/s MSP Interface

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BoD in SURFnet7

NOC engineer Application User NSI NSI Inter Domain

GUI API SURFnet7 BoD SURFnet7 NMS

Identity Provider Group Provider

GUI

MTOSI 19 19

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xx

20

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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?
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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

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A B

Tunnel CIR: 2 node network

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

Future lightpaths Existing lightpaths SLP: static lightpath DLP dynamic lightpath

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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

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2 elevator dilemma

  • Assume 2 elevators, both

with capacity for exact 10 people

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2 elevator dilemma

  • Assume 2 elevators, both

with capacity for exact 10 people Drop at least 1 person and a guitar

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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
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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

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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
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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

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W

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