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MATCHING THE WAN TO BUSINESS NEEDS

James Walker, Vice President Managed Network Services WAN Summit 7th October 2015

THE CHANGING WAN

© 2012 Tata Communications Ltd. All rights reserved. TATA COMMUNICATIONS and TATA are trademarks of Tata Sons Limited in certain countries.

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•  The rise and rise of the cloud •  Bringing challenges of :

•  Integration with legacy systems •  Private vs public connectivity •  Alignment with internal policies, security requirements, regulatory obligations •  Barriers to entry for smaller cloud providers

•  Increasing use of hybrid VPNs •  Cost reductions •  More challenges :

•  Load balancing (MP BGP) •  Asymmetric routing •  Cloud connectivity •  Full dual link utilisation

•  The arrival of early SDWAN services

So, what’s new?

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Customer requirements

Network-centric Application-centric

•  Extensive in-house network expertise •  Complex traffic engineering requirements •  Deterministic behaviour •  High speed core, regional meet-me •  Private network •  Limited public cloud, little if any SaaS •  Tendency to have significant on-premise

applications •  Audit, compliance and security

requirements

•  Limited internal network expertise •  Application performance critical •  Hybrid networks, mix of private and public

traffic •  Want to increase utilisation levels of the

network •  Increasing use of public cloud and SaaS



Network requirements

Network-centric Application-centric

•  Deterministic pathing •  Minimise visibility of customer’s routing

table •  Predictable network performance •  Complex DR scenarios •  Possible overlay networks •  Generally high speed (1G+) and growing •  Challenges around internal cost allocation

and logical separation •  Dynamic bandwidth potentially required •  Limited sites •  Service multiplexing •  “TEaaS”

•  Managed services •  Application visibility and reporting •  Performance optimisation •  Intelligent load balancing, pathing and use

of network resources •  Integration of multiple services (UC,

Internet) •  Connectivity to public cloud •  A network that dynamically reacts to

application performance and needs •  Overlay network requirements •  Typically multi-vendor, multi service


… AND SDWAN HYBRID VPNS

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Let’s start with something very basic

•  No contention in the core

•  SLA guarantees available

•  Premium link

•  Unpredictable with potential contention and jitter

•  Best effort based

•  “Cheap and cheerful” link



A few more scene-setting thoughts •  Last mile connectivity is the biggest cost in a network

•  Secondary circuit is hardly used (traffic flows less than 1% of the time)

•  Network managers are forced to manage congestion on the primary circuit while the secondary circuit lies idle

•  Backup links fail and no-one notices until they’re needed Primary Circuit Secondary Circuit

VPN

•  For short term bursts – apply QOS techniques and don’t increase bandwidth

•  Long term high link utilization – buy more bandwidth, burst or offload traffic to alternate path

•  Frequent path change causes harm

•  Always route critical traffic on the best path

Network management best practice



Now, a little background on SDWAN

This is Cisco IWAN – but most SDWAN solutions have similar concepts •  Traffic is hub and spoke •  Metrics are measured from the hub to the spokes •  Path selection based on metrics •  Path abstraction (in IWAN, using DMVPN technology) •  Hub Master controller automatically pushes policy to

spokes •  Multiple DCs are supported using a concept called a

transit site



•  Questions customers should ask their SDWAN provider •  Do all sites need two connections, or can I have single attached sites? •  Do all sites have to participate in the overlay?

•  What about IaaS sites? •  Do I have to migrate everything at once?

•  Can I control spoke to spoke traffic? •  Can I have different traffic policies at different DCs? •  When the primary fails at the DC, does all traffic fail over to the

alternate path (for hybrid sites, this is the Internet…)? •  What is the impact on router throughput, are older/smaller routers

supported? •  How do I handle local internet breakout at hybrid sites? •  Will my load balancing policy cause any issues?

SDWAN – still evolving

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Asymmetric routing

70-80% reduction



Problem statement Metric based approach – Path Oscillation Problem

Link utilization increases on

last mile

Metric for critical

application (that has the

most stringent requirements)

drops first

Critical applications are offloaded

Offloading causes

metrics to improve

Variable internet

performance impacts

application performance

metrics

Premium applications are offloaded

again. Congestion

reoccurs



•  New applications, cloud and the move to hybrid networking is a very fundamental change •  Local internet breakout, connections to cloud (eg O365, Skype) and legacy applications are very

complex to manage efficiently •  Managing application prioritisation and failover remains difficult

•  Service providers – and the industry – are in a state of flux •  Enterprise customers sit on a spectrum with a spread of requirements which become very different at

the two ends •  SDN and NFV are not yet here and continue to evolve •  Customers have problems now

•  Overlay providers are an attractive option for frustrated enterprises •  … but can introduce rafts of new issues, and not fix the old ones •  There is no silver bullet

•  Back to the future? •  While supporting SDWAN, we are also investing heavily in innovation using “legacy” protocols •  Visibility, efficiency, predictability and control are the objectives

Final thoughts

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THANK YOU

Documents

THE CHANGING WAN - Squarespace · THE CHANGING WAN © 2012 Tata ... • Full dual link utilisation ... • Local internet breakout, connections to cloud (eg O365, Skype)