24
Copyright©2017 NTT corp. All Rights Reserved. P.1 September 28, 2017 APNOMS2017@Seoul Takashi Miyamura 1 , Akira Misawa 2 , Jun-ichi Kani 1 1 NTT Laboratories 2 Chitose Institute of Science and Technology (CIST) Design of Optical Aggregation Network with Carrier Edge Functions Virtualization

Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

  • Upload
    others

  • View
    7

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright©2017 NTT corp. All Rights Reserved.P.1

September 28, 2017

APNOMS2017@Seoul

Takashi Miyamura1, Akira Misawa2, Jun-ichi Kani1

1 NTT Laboratories2 Chitose Institute of Science and Technology (CIST)

Design of Optical Aggregation Network with Carrier Edge Functions

Virtualization

Page 2: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

2Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1. Background

2. Objective

3. Proposed Method

4. Performance Evaluation

5. Conclude

Page 3: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

3Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1.Background2. Objective

3. Proposed Method

4. Performance Evaluation

5. Conclude

Page 4: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

Carrier network architecture

OXC / OADM

IP router

Layer 2 switch

Legend (symbols):

IX

Public cloud(e.g., Amazon)

Internet

OLT

※OLT: Optical Line Terminal, OXC: Optical Cross-connect

Aggregationnetwork

Access net.

Edge router

GW router

OXC

Layer 2 switches

Opt. fiber

Backbone net.

Others

Backbone network:Transport long-haul traffic

Aggregation network:Concentrate user traffic and transport it to the backbone

Access network:Connecting user premises with carrier network

Aggregation network (metro): Transport traffic from access network to backbone network, based on electronic L2 SW.Carrier edge function: provides service-specific functions such as QoS and flow identification at edge router.

Access net.

Page 5: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

5Copyright© 2017 NTT corp. All Rights Reserved.

Recent trend in aggregation networks

①: Introducing NFV for Carrier Edge functions

• Edge functions to be relocated from edge routers to distributed pools of commodity servers

②: TDM/WDM-based Optical Aggregation Network

• WDM ring network to accommodate large-volume traffic efficiently

• Improving efficiency by sharing same wavelength through TDM

OLT

OLT

OLT

OLT

Server farms

TDM/WDM ring

Improving efficiency of wavelength through TDM

Accommodate unpredictable traffic demand changes by NFV

VNF: Virtual Network Function

Re-optimize VNF placement according to uneven resource usage

① NFV for edge functions

② TDM/WDM-based network

Page 6: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

6Copyright© 2017 NTT corp. All Rights Reserved.

① Carrier edge functions virtualization

Advantages:

• Create VNF for each OLT. The VNF can be flexibly placed on any servers among distributed pools of commodity servers.

• Can be live-migrated from an over-loaded server to an under-utilized one in response to unpredictable traffic changes.

Challenges:

• Determine VNF placement considering traffic demand and geographical location (e.g. distance bet. OLT-Server).

Edge routers(dedicated hardware)

Conventional network

QoS SBC

BAS ACL

NFV

Commodity servers

Edge functions

VNF

#1#2

#3

#4VNF

VNF

VNF

VNF (virtual network function): Implementation as software

Page 7: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

7Copyright© 2017 NTT corp. All Rights Reserved.

② TDM/WDM-based aggregations network

Advantages:

• To cope with bursty traffic, enable the same wavelength channel to be shared by multiple OLTs through DBA or other TDM technologies.

Challenges:

• How to efficiently select route for P2MP wavelength path considering bandwidth requirement of each OLT?

[1] K. Hattori et al., IEICE Trans. Electron., Vol. E99-C, No. 2, pp. 189-201,February 2016.

1time 1

timeNE

Optical copler

O/E conversion

1time 12

Access node

WDM link WDM link

2

OLT1

OLT2

ES(Edge server)

DBADBA

DBA

Page 8: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

8Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1. Background

2.Objective3. Proposed Method

4. Performance Evaluation

5. Conclude

Page 9: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

Conventional: Deployment of edge routers– Edge routers accommodate fixed group of OLTs based on location. This

causes congested or under-utilized routers due to unpredictable traffic demand changes

Our approach: NFV for carrier edge fucntions– Can accommodate OLTs independent of location, so it can provides

robustness⇒However, consumes more network resources if we allocate VNFs on geographically remote server.

Issues in carrier edge virtualization

Edge servers (ES)

1 2

VNF

OLT

Conventional

Edge routers

3 4 5

Seoul Busan Jeju

Degrade efficiency if traffic demand of OLTs varies widely

1 4 2 3 5

1 2 OLT3 4 5

Improve efficiency to optimize accommodation according to demand changes

Our approach: NFV for edge functions

More resources are consumed if server is far distant from OLT

Seoul Busan Jeju

Page 10: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

• Minimize network cost while efficiently utilizing server resources.

– For optimal VNF placement, we need to consider resource requirements of optical network in addition to server resources

– In optical aggregation network, we need to consider the sharing of wavelength paths as we can use P2MP paths connecting server and OLTs

⇒ Establish optimal design method for VNF placement and P2MP path routing

Objective

1 2 1 2

• Consume 3 WDM links• Disperse server load

• Consume 2 WDM links• Server may be over-loaded

VNF

OLT

ESES

OLT

1

2

1 2

Page 11: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

11Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1. Background

2. Objective

3.Proposed Method4. Performance Evaluation

5. Conclude

Page 12: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

We formulate the design problem as mixed integer linear programming (MILP).●Objective function:• Minimize weighted sum of network cost and max server load●Variables:• P2MP wavelength paths between server and OLTs• VNF placement (Select ES to be accommodated)

Proposed design method

Weight parameter

Network cost Max server load

:

Total of WDM links used for P2MP pathsES load

Max load

Page 13: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

Problems1:

Place VNFs on ES

Network model

: ES : OLT

: OADM

Physical topology design

(ES~OLT)

Logical topology design(VNF~OLT)

: VNF

1

2

2

3

1

2

3

1 3

Select ES to accommodate VNF

1 2 3

TDM-WDMnetwork

: Wavelength path

Legends

VNF OLT

Problem 2:

Compute route bet. ES and OLT.

Edge server

OLT

1 2 3

Page 14: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

Copyright© 2017 NTT corp. All Rights Reserved.

• VNF placement– Assign binary variables to candidate ES for VNF

placement

• Route for P2MP wavelength path– Configure logical flow bet. VNF~OLT.

– Find route for P2MP path minimize network cost while accommodating traffic demand of logical flows.

Overview of MILP formulations

1 2 3

kVNF

VNF placement P2MP wavelength path

1 2 3 OLT

1 2 3

Traffic

demand

D1

D1+D2

≦Bandwidth of λ

X1k

=1 (accommodate VNF k)

=0 (no placement)

X1k

Binary variable

X2k X3

k

ES

ES

Traffic

demand

D2

Page 15: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

15Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1. Background

2. Objective

3. Proposed Method

4.Performance Evaluation5. Conclude

Page 16: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

16Copyright© 2017 NTT corp. All Rights Reserved.

Objective of performance evaluation

①: Design of parameter α• Parameter α governs the weight of network cost on server

load

②: Effectiveness• Effectiveness regarding reduction in network cost and

server load

③: Robustness against unpredictable traffic changes

• Evaluate impact of increased variations of traffic demandObjective function

Wight parameter

Network cost Max server load

Page 17: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

17Copyright© 2017 NTT corp. All Rights Reserved.

Evaluation conditions

• Topology: 10-node multi-ring

• Traffic demand: Zipf distribution T(x)=b*x-β

• Reference method: MinHop, RoundRobin

Network topology MinHop

RoundRobin

n

1 2 3

OLT

Select server with minimum

hop

1 2 3

i j k

Select server in RoundRobin

orderOLT

OLT

Page 18: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

18Copyright© 2017 NTT corp. All Rights Reserved.

0

0.5

1

1.5

2

0 1 10 100 1000

Result①: Design of parameter α

• To configure parameter α around 0~1, we can efficiently disperse server load while avoiding increase in network cost.

Net

wo

rk c

ost

/M

ax s

erv

er

load

Optimization parameter α

Max server load

Network cost

Minimizenetwork cost

Minimizeserver load

Page 19: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

19Copyright© 2017 NTT corp. All Rights Reserved.

Result ②-1: Effectiveness

• Compare network cost for various traffic demand

• Proposed method reduced by up to 21%

Net

wo

rk c

ost

Average traffic demand※

(※Normalized by λ bandwidth)

0

0.5

1

1.5

2

0.1 0.2 0.3 0.4 0.5 0.6

Proposed

MinHop

RoundRobin

ReductionBy 21%

10%increase

Page 20: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

20Copyright© 2017 NTT corp. All Rights Reserved.

Result ②-2 Effectiveness

• Compare max server load for various traffic demand

• Proposed method reduced by up to 30%

Max

se

rver

load

0

2

4

6

8

0.1 0.2 0.3 0.4 0.5 0.6

Average traffic demand※

(※Normalized by λ bandwidth)

Proposed

MinHop

RoundRobin

ReductionBy 30%

Page 21: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

21Copyright© 2017 NTT corp. All Rights Reserved.

0

0.5

1

1.5

2

0.5 1 1.5 2

0

0.5

1

1.5

2

0.5 1 1.5 2

Result ③ Robustness

• Evaluate robustness for various traffic variations β

• Proposed method ensures robustness against traffic variations

Proposed

MinHopRoundRobin

Traffic variations (β)

Proposed

RoundRobin

MinHop

Traffic=50

Net

wo

rk c

ost

Max

se

rve

r lo

ad

Traffic variations (β)

Zipf distribution T(x)=b*x-β

Sharp fluctuations

Page 22: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

22Copyright© 2017 NTT corp. All Rights Reserved.

Outline

1. Background

2. Objective

3. Proposed Method

4. Performance Evaluation

5.Conclude

Page 23: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

23Copyright© 2017 NTT corp. All Rights Reserved.

Conclusions

• We studied the optimal design of optical aggregation networks with carrier edge function virtualization.• NFV improves efficiency of server resources for carrier

edge functions.

• Consider joint optimization problem that minimizes network cost and maximum server load.

• Formulate the problem as mixed integer linear programming.

• We quantitatively evaluated effectiveness of the optimal aggregation network design with VNF placement.• It reduced the maximum server load and network cost by up

to 30% and 21%, respectively.

• Can improve resource efficiency and robustness to unpredictable demand changes.

Page 24: Design of Optical Aggregation Network with Carrier Edge ... · aggregation networks with carrier edge function virtualization. • NFV improves efficiency of server resources for

24Copyright© 2017 NTT corp. All Rights Reserved.

Thank you

for your kind attention.