WAN Design Considerations

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WAN Design Considerations
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WAN Design Considerations

• Application Performance Management
• Disaster Recovery

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Application Performance Management
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Causes for High WAN Traffic

• LAN/WAN capacity mismatch
• More application traffic
• Webification
• Distributed applications
• Server consolidation
• Voice/video/data convergence
• Disaster readiness
• Recreational traffic
• Security
• New habits

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Typical Traffic Profile
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Solving Traffic Problems

• Improve and protect the performance of your
  urgent and critical business applications
• Pace important but less urgent traffic (such as
  large email attachments)
• Spot and stop malicious security threats
• Limit recreational traffic and its impact on
  critical traffic
• Provision bandwidth for streaming applications to
  ensure smooth reception
• Compress traffic to fit more data through the
  constrained links

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Traffic Shaping Appliances
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Traffic Analysis
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Traffic Analysis
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Effect of Traffic Shaping
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Compression
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Approaches to QoS
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Disaster Recovery
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Cost of Downtime
Availability Yearly Downtime 90 876
hours 99 87 hours, 36 minutes 99.9
8 hours, 45 minutes 99.99 52 minutes, 33
seconds 99.999 5 minutes, 15 seconds
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Costs of Downtime Without Recovery Plan

• 93 percent of companies without a recovery plan
  go out of business within five years of a loss
  disaster
• 50 percent of those businesses who do not recover
  their data within 10 business days never fully
  recover
• Critical business functions cannot continue for
  more than 4.8 days without a data recovery
  process

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Elements of a Disaster Recovery Plan

• Electrical
• 45 of data loss is due to electrical problems
• Redundant power feeds
• Underground feeds
• Surge protection
• UPS
• Back up generators
• Hardware and software
• 41 of problems are due to hardware or software
  failure
• Redundant hardware systems
• Backup systems with failure recovery
• WAN diversity
• Diverse routes
• Redundant data centers

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Diverse Routing (Link Redundancy)
POPs may be from same carrier or may be from
different carriers
Traffic may be balanced across multiple links or
one may serve as a failover depending on routing
protocols used and carriers capabilities.
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Redundant Data Centers
All traffic to primary is also routed to
secondary so that, in the invent of failure of
link to primary or disaster at primary, the
secondary can take over automatically and
seamlessly.
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Diverse routes and data centers