DiffServ

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DiffServ

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(Committed Access Rates) X. Y. N. N. N1. N2. Feasible region ... X. Y. N. N. For 'large links', the. variance is small. = Static Dynamic. However, rates change ... – PowerPoint PPT presentation

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Title: DiffServ

1
DiffServ

An Overview
Jean WalrandEECS

2
Outline

DiffServ
Goal
Solution
Worst Case Admission Control
Measurement-Based Admission Control
Bandwidth Allocation
A Note on CoS
Notes on Smart Networks Project

3
DiffServ

Goal

CoS without per-connection state

Solution

No route-pinning (OSPF-BGP routing)
Planning and operations based on aggregate
statistics and worst-case routing
Peer-to-peer SLAs that specify total rate but not
traffic destination

4
DiffServ (continued)
Policing Shaping
5
DiffServ (continued)
DiffServ SLA Worst Case Admission Control
Ingress 3
Ingress 3
Ingress 1
Ingress 1
Ingress 2
Ingress 2
Worst Case
Typical Case
Terribly wasteful!
6
DiffServ (continued)
Worst Case R ? 10

Example

R
Symmetric Case R ? 20
10
R
Worst Case, 1F R ? 5
10
Symm. Case, 1F R ? 10
10
R
7
DiffServ (continued)
DiffServ SLA Measurement-Based Admission Control
Admit if peak(new) lt Gap at all times
8
Bandwidth Allocation

Problems
How to share bandwidth
How to renegotiate SLAs
Issues
Scalability
Efficiency
Fairness, Optimality, ...

9
Bandwidth Allocation (cd)
Sharing one link
10
Bandwidth Allocation (cd)
Dynamic
11
Bandwidth Allocation (cd)
N1
N2
Admission policies SLAs (Committed Access Rates)
Static
12
Bandwidth Allocation (cd)
13
Bandwidth Allocation (cd)
Closer Look
Assume Poisson demands, i.i.d. holding times ...
For large links, the variance is small. gt
Static ? Dynamic
However, rates change gt must adapt
14
Bandwidth Allocation (cd)
Proposed Adaptation Scheme Renegotiate
blocks of permits based on thresholds
4
5
15
20
6
7
5
6
7
40
15
Bandwidth Allocation (cd)