Enterprise Bandwidth Management

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Enterprise Bandwidth Management

• Bandwidth Management in the enterprise network.
• -Senthil Rajasekharan

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Why we need Bandwidth Management ?

• Growing Bandwidth Hungry Applications in the
  enterprise !
• ERP applications, Desktop Multimedia tools, X
  tools , Networked Storage devices.
• Bursty nature of traffic causes Gateway clogs ,
  increasing packet delay and loss hence decreased
  throughput
• SNMP does it really manage the network ?

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Possible Approaches to Bandwidth Management

• Essentially avoiding n/w congestion.
• Increasing Network bandwidth and removing network
  bottlenecks
• Queuing Schemes
• Traffic Shaping leaky token buckets
• TCP Rate Control
• Admission Control

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Class based Queuing

• Traffic classes divided into a hierarchy of
  classes.
• Classification based on any combination of IP
  address, protocols, application types.
• Applies to both TCP and UDP traffic flows.

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Traffic Shaping

• Leaky bucket scheme.
• Prioritizing/Coloring and metering.
• Token bucket scheme.

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Shaping (contd.)
data

• Designed for cell traffic but can also be applied
  for datagrams.
• Bursts are smoothed
• r determines the output data rate
• b sets the delay bound of the cell or packet

b
r
A Simple Leaky Bucket Scheme
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Shaping (contd .)

• Marking/Tagging
• Packets or cells can be tagged /marked with a
  priority code.
• All nodes should be able to understand the
  tag/mark !!

Token Bucket
r
b
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TCP Rate Control
TCP Sender
TCP Receiver

• Shaping TCP traffic by pruning receiver
  advertised window.
• Changes in the TCP end-end semantics.

Data 20000 - 21000
ACK 21000 Win 4000
ACK 20000 Win 2000
Traffic Shaper
Data 21000-22000
ACK 21000 Win 2000
Data 22000-23000
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Policy Networking
To Policy repository via LDAP
To authentication servers

• Common Open Policy Server COPS
• Policies State who has access to what, how and
  when ??

PDP
PEP sends policy elements with request
COPS
PDP returns decision (possibly inability to
enforce policy)
PEP
Connections secured through IPSec
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Future Trends

• VPNs and SLAs.
• Traffic Engineering in the Core
• More Fiber Backbones !!