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Selective Placement of Caches for Hash-Based Off-Path Caching in ICN* Anshuman Kalla 1 *Indian Journal of Science and Technology, Vol 9 (37), October 2016 DOI: 10.17485/ijst/2016/v9i37/100323 For reading mode, Adobe Reader use Ctrl + H and Foxit Reader use F11

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Page 1: Selective placement of caches for hash based off-path caching in icn slides

Selective Placement of Caches for Hash-Based Off-Path Caching in ICN*

Anshuman Kalla

1

*Indian Journal of Science and Technology, Vol 9 (37), October 2016

DOI: 10.17485/ijst/2016/v9i37/100323

For reading mode, Adobe Reader – use Ctrl + H and Foxit Reader – use F11

Page 2: Selective placement of caches for hash based off-path caching in icn slides

In-Network Caching in ICN

• Research based resurgence in the field of networking seems to have culminated in form of ICN– since it has the capability to conciliate in a unified manner all the

existing & anticipated issues

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Page 3: Selective placement of caches for hash based off-path caching in icn slides

In-Network Caching in ICN

• Research based resurgence in the field of networking seems to have culminated in form of ICN– since it has the capability to conciliate in a unified manner all the

existing & anticipated issues

• In-network caching has evidently emerged as an indispensable core functionality of ICN– expected to play a vital role in ameliorating performance

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Page 4: Selective placement of caches for hash based off-path caching in icn slides

In-Network Caching in ICN

• Research based resurgence in the field of networking seems to have culminated in form of ICN– since it has the capability to conciliate in a unified manner all the

existing & anticipated issues

• In-network caching has evidently emerged as an indispensable core functionality of ICN– expected to play a vital role in ameliorating performance

• Advantages of in-network caching, related issues, factors affecting, performance metrics etc. – Have been discussed in detail

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Page 5: Selective placement of caches for hash based off-path caching in icn slides

In-Network Caching in ICN

• Research based resurgence in the field of networking seems to have culminated in form of ICN– since it has the capability to conciliate in a unified manner all the

existing & anticipated issues

• In-network caching has evidently emerged as an indispensable core functionality of ICN– expected to play a vital role in ameliorating performance

• Advantages of in-network caching, related issues, factors affecting, performance metrics etc. – Have been discussed in detail *

* A. Kalla, SK Sharma, “A Constructive Review of In-Network Caching: A Core Functionality of ICN,” Proc. IEEE International Conference (ICCCA), pp 567 – 574, 2016

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Page 6: Selective placement of caches for hash based off-path caching in icn slides

Background & Motivation

• Off-Path caching has preliminarily shown better results – In terms of hit ratio, retrieval delay, cache diversity, server load etc.

– as compared on-path and edge caching [see references in the paper]

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Page 7: Selective placement of caches for hash based off-path caching in icn slides

Background & Motivation

• Off-Path caching has preliminarily shown better results – In terms of hit ratio, retrieval delay, cache diversity, server load etc.

– as compared on-path and edge caching [see references in the paper]

• One of the practical & popular ways of implementing pervasive off-path caching is– Hash-based off-path caching that uses hash function

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Page 8: Selective placement of caches for hash based off-path caching in icn slides

Background & Motivation

• Off-Path caching has preliminarily shown better results – In terms of hit ratio, retrieval delay, cache diversity, server load etc.

– as compared on-path and edge caching [see references in the paper]

• One of the practical & popular ways of implementing pervasive* off-path caching is– Hash-based off-path caching that uses hash function

* Pervasive means all the nodes are enabled with in-network caching capability

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Page 9: Selective placement of caches for hash based off-path caching in icn slides

Background & Motivation

• Off-Path caching has preliminarily shown better results – In terms of hit ratio, retrieval delay, cache diversity, server load etc.

– as compared on-path and edge caching [see references in the paper]

• One of the practical & popular ways of implementing pervasive off-path caching is– Hash-based off-path caching that uses hash function

• Nevertheless, one downside of off-path caching is– Increase in intra-domain link load to achieve required gain

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Page 10: Selective placement of caches for hash based off-path caching in icn slides

Background & Motivation

• Off-Path caching has preliminarily shown better results – In terms of hit ratio, retrieval delay, cache diversity, server load etc.

– as compared on-path and edge caching [see references in the paper]

• One of the practical & popular ways of implementing pervasive off-path caching is– Hash-based off-path caching that uses hash function

• Nevertheless, one downside of off-path caching is– Increase in intra-domain link load to achieve required gain

• Moreover, internal link stress and retrieval delay depends on – Network topology

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Page 11: Selective placement of caches for hash based off-path caching in icn slides

Aim

• With this background the question raised is:

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Does there exists a selective cache allocation map which could be conducive in achieving

• Smaller ‘average retrieval delay’ and simultaneous

• Lower ‘maximum intra-domain link-stress’

while keeping the other relevant metrics unaltered as compared to pervasive cache allocation?

Page 12: Selective placement of caches for hash based off-path caching in icn slides

Aim

• With this background the question raised is:

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Does there exists a selective cache allocation map* which could be conducive in achieving

• Smaller ‘average retrieval delay’ and simultaneous

• Lower ‘maximum intra-domain link-stress’

while keeping the other relevant metrics unaltered as compared to pervasive cache allocation?

* Cache allocation or placement implies configuring the nodes with content storage capacity

Page 13: Selective placement of caches for hash based off-path caching in icn slides

Aim

• With this background the question raised is:

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Does there exists a selective cache allocation map* which could be conducive in achieving

• Smaller ‘average retrieval delay’ and simultaneous

• Lower ‘maximum intra-domain link-stress’

while keeping the other relevant metrics unaltered as compared to pervasive cache allocation?

If so, what could be a simple way to find such a selective placement of caches* for hash-based off-path caching?

* Cache allocation or placement implies configuring the nodes with content storage capacity

Page 14: Selective placement of caches for hash based off-path caching in icn slides

Aim

• To ensure profitable, economic & selective placement of caches such that the placement– Tends to reduce simultaneously average retrieval delay &

maximum internal link-stress

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Page 15: Selective placement of caches for hash based off-path caching in icn slides

Aim

• To ensure profitable, economic & selective placement of caches such that the placement– Tends to reduce simultaneously average retrieval delay &

maximum internal link-stress

• We propose simple yet elegant heuristic algorithm to find selective cache allocation map – by strategically identifying & excluding bad node-positions

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Page 16: Selective placement of caches for hash based off-path caching in icn slides

Aim

• To ensure profitable, economic & selective placement of caches such that the placement– Tends to reduce simultaneously average retrieval delay &

maximum internal link-stress

• We propose simple yet elegant heuristic algorithm to find selective cache allocation map – by strategically identifying & excluding bad node-positions

• Rationale:– There are few nodes in network which if selected for caching

causes adverse effect

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Page 17: Selective placement of caches for hash based off-path caching in icn slides

Aim

• To ensure profitable, economic & selective placement of caches such that the placement– Tends to reduce simultaneously average retrieval delay &

maximum internal link-stress

• We propose simple yet elegant heuristic algorithm to find selective cache allocation map – by strategically identifying & excluding bad node-positions

• Rationale:– There are few nodes in network which if selected for caching

causes adverse effect

• To the best of our knowledge, the work is first attempt – to explore selective placement of caches for hash-based off-path caching

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Page 18: Selective placement of caches for hash based off-path caching in icn slides

Cost Computation of Nodes

• Cost for every node in the network is calculated

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Page 19: Selective placement of caches for hash based off-path caching in icn slides

Cost Computation of Nodes

• Cost for every node in the network is calculated

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• Since uniform rate of request arrival at ingress nodes is considered thus

Page 20: Selective placement of caches for hash based off-path caching in icn slides

Cost Computation of Nodes

• Cost for every node in the network is calculated

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• Since uniform rate of request arrival at ingress nodes is considered thus

H = average hit ratio for the case of pervasive hash-based off-path caching

dxy = delay encountered to reach destination y from source x using the shortest path

I = set of ingress nodes, V = set of nodes in network topology

e ∈ E denotes egress node that falls over the shortest path & is connected to server

Page 21: Selective placement of caches for hash based off-path caching in icn slides

Cost Computation of Nodes

• Cost for every node in the network is calculated

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• Since uniform rate of request arrival at ingress nodes is considered thus

H = average hit ratio for the case of pervasive hash-based off-path caching

dxy = delay encountered to reach destination y from source x using the shortest path

I = set of ingress nodes, V = set of nodes in network topology

e ∈ E denotes egress node that falls over the shortest path & is connected to server

• Using these values, a ordered list of nodes is prepared In the descending order of cost Cr i.e. is from most costly to least costly

Page 22: Selective placement of caches for hash based off-path caching in icn slides

Performance Metrics

• Average Retrieval Delay

– Delay encountered on an average to fetch requested content irrespective of source-of-request & point-of-retrieval

– Smaller the delay better is the user’s QoE

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Page 23: Selective placement of caches for hash based off-path caching in icn slides

Performance Metrics

• Average Retrieval Delay

– Delay encountered on an average to fetch requested content irrespective of source-of-request & point-of-retrieval

– Smaller the delay better is the user’s QoE

• Link Stress

– For an intra-domain link, the metric indicates the volume of the traffic passed through it

– The value of link stress for the most heavily loaded internal link is termed as maximum internal link stress

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Page 24: Selective placement of caches for hash based off-path caching in icn slides

Performance Metrics

• Hit Ratio

– Requests being satisfied by contents residing at in-network caches to the total requests received

– Higher is the hit ratio, lower is the traffic delegated over the expensive external links and lesser is the load on origin server

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Page 25: Selective placement of caches for hash based off-path caching in icn slides

Performance Metrics

• Hit Ratio

– Requests being satisfied by contents residing at in-network caches to the total requests received

– Higher is the hit ratio, lower is the traffic delegated over the expensive external links and lesser is the load on origin server

• Unique Contents Cached

– Total number of distinct contents being cached by all the in-network caches collectively

– More is the unique contents cached better is the cache diversity

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Page 26: Selective placement of caches for hash based off-path caching in icn slides

Environment Setup

• Exodux US, a PoP level topology from Rocketfuel[Reference # 22 in the paper] is used

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Page 27: Selective placement of caches for hash based off-path caching in icn slides

Environment Setup

• Exodux US, a PoP level topology from Rocketfuel[Reference # 22 in the paper] is used

• About 8% of nodes were randomly appointed as egress nodes (connected to origin server)

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Page 28: Selective placement of caches for hash based off-path caching in icn slides

Environment Setup

• Exodux US, a PoP level topology from Rocketfuel[Reference # 22 in the paper] is used

• About 8% of nodes were randomly appointed as egress nodes (connected to origin server)

• Approx. 55% of nodes were randomly selected as ingress nodes (connected to clients i.e. users)

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Page 29: Selective placement of caches for hash based off-path caching in icn slides

Environment Setup

• Exodux US, a PoP level topology from Rocketfuel[Reference # 22 in the paper] is used

• About 8% of nodes were randomly appointed as egress nodes (connected to origin server)

• Approx. 55% of nodes were randomly selected as ingress nodes (connected to clients i.e. users)

• Aggregate network cache size is chosen to be 10% of content population

2/24/2017 29Anshuman Kalla

Page 30: Selective placement of caches for hash based off-path caching in icn slides

Environment Setup

• Exodux US, a PoP level topology from Rocketfuel[Reference # 22 in the paper] is used

• About 8% of nodes were randomly appointed as egress nodes (connected to origin server)

• Approx. 55% of nodes were randomly selected as ingress nodes (connected to clients i.e. users)

• Aggregate network cache size is chosen to be 10% of content population

• Rest of the parameters used are as per table, next

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Page 31: Selective placement of caches for hash based off-path caching in icn slides

Parameters Used For Evaluation

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Parameters Values

Total number of nodes 79

Number of server one

Number of egress nodes (connected to server) 6

Number of ingress nodes (connected to users) 44

Content population 79000

Aggregate network cache size 7900

Cache size per node 100

Popularity distribution of content requests Zipf (α = 0.8)

Delay to reach origin server from egress nodes 100 ms

Cache size per node Uniform

Rate of request arrival at ingress nodes Uniform

Content size Homogeneous

Cache replacement policy LRU

Number of iterations carried out for the selected topology 39

Number of runs per iteration of algorithm 1 20

Number of requests simulated per run (i.e. after launch of hash-based off-path

caching)500,000

Routing Shortest Path

Links between users and ingress nodes Bi-directional

Network regime Congestions Free

Page 32: Selective placement of caches for hash based off-path caching in icn slides

Points To Note

• First

– Evaluation takes into account only link propagation delay

– Factors like queuing delay, packet loss, cross traffic etc. have not been incorporated for preliminary evaluation

2/24/2017 32Anshuman Kalla

Page 33: Selective placement of caches for hash based off-path caching in icn slides

Points To Note

• First

– Evaluation takes into account only link propagation delay

– Factors like queuing delay, packet loss, cross traffic etc. have not been incorporated for preliminary evaluation

• Second

– Iteration denotes a repetitive process of debarring increasing number of nodes from caching, whereas

– Run indicates an act of deploying hash-based off-path caching with a selective placement of caches

– As per last table, 20 runs per iteration have been carried out during the simulations.

2/24/2017 33Anshuman Kalla

Page 34: Selective placement of caches for hash based off-path caching in icn slides

Points To Note

• Third

– Based on the hash function being used the mapping of contents to a designated off-path caches could be entirely different

– Thus for better evaluation content-to-cache mapping is being changed for every run

– This explains the reason behind multiple runs per iteration

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Page 35: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Page 36: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

2/24/2017 36Anshuman Kalla

Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss

Page 37: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

2/24/2017 37Anshuman Kalla

Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss77410

Selective Placement

Page 38: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

2/24/2017 38Anshuman Kalla

Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss77410

Selective Placement

Page 39: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

2/24/2017 39Anshuman Kalla

Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss

78.9465

77410

Selective Placement

Page 40: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

2/24/2017 40Anshuman Kalla

Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss

84.5661

81784

78.9465

77410

Selective PlacementPervasive Caching

Page 41: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Number of nodes debarred from caching

Ave

rage

Ret

riev

al D

ela

y

Number of nodes debarred from caching

Max

imu

m L

ink

Stre

ss

84.5661

81784

78.9465

77410

Selective PlacementPervasive Caching

Gain = 5.6196 i.e. 6.65%

Gain = 4374i.e. 5.35%

Page 42: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Content Descending in Popularity

Co

nte

nt

Wis

e A

vera

ge R

etr

ieva

l De

lay

Content Descending in Popularity

Co

nte

nt

Wis

e H

it R

atio

Page 43: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Placement of

CachesHit Ratio

Average

Retrieval Delay

Cache

Diversity

Maximum Link

Stress

Pervasive 0.4635 84.5661 7900 81784

Selective 0.4638 78.9465 7900 77410

Page 44: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Placement of

CachesHit Ratio

Average

Retrieval Delay

Cache

Diversity

Maximum Link

Stress

Pervasive 0.4635 84.5661 7900 81784

Selective 0.4638 78.9465 7900 77410

• The proposed algorithm is able to achieve

– 6.65% and 5.35% reduction in average retrieval delay and maximum internal link stress respectively

Page 45: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Placement of

CachesHit Ratio

Average

Retrieval Delay

Cache

Diversity

Maximum Link

Stress

Pervasive 0.4635 84.5661 7900 81784

Selective 0.4638 78.9465 7900 77410

• The proposed algorithm is able to achieve

– 6.65% and 5.35% reduction in average retrieval delay and maximum internal link stress respectively

• Quantitatively the gain might not be high but qualitatively the gain comes at no trade-off

– That is without sacrificing any other relevant performance metrics

Page 46: Selective placement of caches for hash based off-path caching in icn slides

Results and Discussion

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Placement of

CachesHit Ratio

Average

Retrieval Delay

Cache

Diversity

Maximum Link

Stress

Pervasive 0.4635 84.5661 7900 81784

Selective 0.4638 78.9465 7900 77410

• The proposed algorithm is able to achieve

– 6.65% and 5.35% reduction in average retrieval delay and maximum internal link stress respectively

• Quantitatively the gain might not be high but qualitatively the gain comes at no trade-off

– That is without sacrificing any other relevant performance metrics

• The nodes debarred are not to be upgraded with ICN functionalities which implies lower cost

Page 47: Selective placement of caches for hash based off-path caching in icn slides

Thank You!

2/24/2017 Anshuman Kalla 47