Optimizing Flow Bandwidth Consumption with Traffic-diminishing - - PowerPoint PPT Presentation

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Optimizing Flow Bandwidth Consumption with Traffic-diminishing - - PowerPoint PPT Presentation

Optimizing Flow Bandwidth Consumption with Traffic-diminishing Middlebox Placement Yan Yang Chen en, Jie Wu, and Bo Ji Center for Networked Computing Temple University, USA VNF: Evolution of Network Service l Network Function Virtualization


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Optimizing Flow Bandwidth Consumption with Traffic-diminishing Middlebox Placement

Yan Yang Chen en, Jie Wu, and Bo Ji

Center for Networked Computing Temple University, USA

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VNF: Evolution of Network Service

l Network Function Virtualization (NFV)

¡ Virtualizing network functions into software building blocks

l Virtualized Network Function (VNF) or Middlebox

¡ Software implementation of network functions ¡ Improve performance & enhance security

l Examples l Middlebox Deployment

¡ Deployment location selection on multiple servers

Firewall NAT Proxy

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l VNFs may change flow rates in different ways

¡ Citrix CloudBridge WAN accelerator: 20% (diminishing) ¡ BCH(63,48) encoder: 130% (expanding)

VNF Traffic Changing Effects [1]

[1] Traffic Aware Placement of Interdependent NFV Middleboxes (INFOCOM ’17)

1 1 1 1 1 Data Checksum

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SLIDE 4

A motivating example

Traffic-diminishing ratio

  • f VNF m: 0.5

Initial flow rate: f1 (4), f2 (2), f3 (2), f4 (2) 0.5*4*2+2*2+2+2=12 0.5*4*2+ 0.5* 2*2+ 0.5* 2+ 0.5* 2=8 Total bandwidth consumption

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SLIDE 5
  • 2. Our model

l Problem

¡ Deploy a single type of VNFs with traffic-

diminishing effect into the network

l Objective

¡ Minimize total bandwidth consumption of all flows

  • n all links along their paths

l Constraint

¡ Each flow gets processed ¡ Deploy a limited number of the single type of VNFs

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SLIDE 6
  • 3. Problem Formulation

A mathematical optimization problem on minimizing total flow bandwidth consumption

Single flow

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SLIDE 7

l NP-hard l Decrement function

¡ Decrement of total bandwidth consumption compared to no VNFs

l Marginal decrement

¡ Additional bandwidth decrement by deploying on 𝒯 beyond 𝒬

l Decrement function is submodular

¡ More VNFs, less bandwidth consumption ¡ Flow gets processed no later than 𝒬

  • 4. Solution for general topologies
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SLIDE 8
  • 4. Solution for general topologies (cont’d)

l Solution

¡ General Topology Placement (GTP)

l Steps

¡ Iteratively select v ∈ V with the maximum marginal

decrement until all flows are fully served

l Approximation ratio 1 −

! "

l Time complexity (|V|: #vertices)

¡ O(|V|2 log |V |)

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SLIDE 9
  • 5. Two solutions for trees

Solution 1: Dynamic Programming (DP)

l 𝐺(𝑤, 𝑙)

¡ Minimum total occupied bandwidth of all flows with 𝑙 deployed

middleboxes in subtree 𝑈v rooted at 𝑤

¡ All flows get fully processed in Tv

l 𝑄(𝑤, 𝑙, 𝑐)

¡ Same as F(v,k) ¡ When flows with only a total bandwidth 𝑐 processed

l Optimal solution l Time complexity (|V|: #node, 𝑠

!"#: largest flow rate) ¡ 𝑃(|𝑊| (log |𝑊|)!𝑠

"#$)

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Solution 1: Dynamic Programming (DP)

Partially processed (b) Processed on v (a) Subtree fully processed Fully processed

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Solution 2: Heuristic Algorithm for Trees (HAT)

l Lowest Common Ancestor (LCA)

¡ LCA(v,w): lowest vertex have both v and w as descendants

l Steps

¡ Deploy one VNF on each leaf vertex ¡ Delete two VNFs on v and w with minimum difference of

the total bandwidth value

¡ Place one VNF on LCA(v,w) ¡ Until total number of deployed VNFs no more than k

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  • 4. Solution for trees (cont’d)

l Maintenance of all difference values

¡ Min-heap ¡ Improve time efficiency

l Time complexity

¡ O(|V |2 log |V |) ¡ |V|: #vertices

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  • 7. Simulation

l Comparison algorithms

¡ Random

l Randomly deploy k VNFs

¡ Best-effort

l Deploy on the vertex, which can reduce the total

bandwidth of flows most, until k VNFs are deployed l Our proposed algorithms

¡ General topo

l Alg. GTP

¡ Tree topo

l Algs. GTP, DP, HAT

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Settings

l Topology l Middlebox traffic-diminishing ratio

¡ From 0 (e.g., spam filters) to 0.9 (e.g., traffic optimizer) with a

stride of 0.1

¡ Additional simulation on spam filter

l Flow rate distribution

¡ CAIDA data center 1-hour packet trace

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Simulation results of tree

l Alg. DP performs

best for all four variables

l k = 1, only one

feasible placement plan for all methods

l Traffic-changing

ratio has the largest impact on the bandwidth consumption

l Random has the

biggest fluctuation

Tree Topology

15 20 25 30 Topology size 0.5 1 1.5 2 2.5 3 Bandwidth consumption 105

Random Best-effort GTP HAT DP

5 10 15 k 0.6 0.8 1 1.2 1.4 1.6 Bandwidth consumption 105

Random Best-effort GTP HAT DP

0.2 0.4 0.6 0.8 Traffic-changing ratio 0.5 1 1.5 2 2.5 Bandwidth consumption 105

Random Best-effort GTP HAT DP

0.3 0.4 0.5 0.6 0.7 0.8 Flow density 0.8 1 1.2 1.4 1.6 1.8 2 Bandwidth consumption 105

Random Best-effort GTP HAT DP

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SLIDE 16

Simulation results of general topology

l Alg. GTP always

consumes the smallest bandwidth

l Error bars become

shorter

l Bandwidth consumption

increases faster in fig. b when ratio ranges from 0.4 to 0.6

l When flow density is

lower than 0.4 in fig. c, little difference among three algorithms

General Topology

12 14 16 18 20 22 k 3.5 4 4.5 5 5.5 Bandwidth consumption 105

Random Best-effort GTP

0.2 0.4 0.6 0.8 Traffic-changing ratio 3 3.2 3.4 3.6 3.8 4 Bandwidth consumption 105

Random Best-effort GTP

0.3 0.4 0.5 0.6 0.7 0.8 Flow density 2.0 4.0 6.0 8.0 Bandwidth consumption 105

Random Best-effort GTP

20 30 40 50 Topology size 2.0 4.0 6.0 8.0 Bandwidth consumption 105

Random Best-effort GTP

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Simulation results (cont’d)

l Flow density plays a more important role in affecting

the total bandwidth consumption

l When flow density doubles from 0.3 to 0.6,

bandwidth consumption in tree increases 30.2%, while increment is only 25.6% in general topo

Spam Filter (Traffic diminishing ratio: 0)

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Conclusion and Future Work

l Problem

¡ Deploy a limited number of traffic-diminishing VNFs ¡ All flows get processed

l Objective

¡ Minimize total bandwidth consumption

l Solutions

¡ Tree: optimal and greedy ¡ General graph: performance-guaranteed

l Future Work

¡ Traffic-expanding VNFs ¡ Service chain: an ordered set of multiple VNFs

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Optimizing Flow Bandwidth Consumption with Traffic-diminishing Middlebox Placement

Thank you!