BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS DEPARTMENT OF TELECOMMUNICATIONS AND MEDIA...

BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICSDEPARTMENT OF TELECOMMUNICATIONS AND MEDIA INFORMATICS


On the Optimal Configuration of Metro Ethernet for Triple Play

András Kern, Tibor Cinkler, István Moldován

2nd EuroNGI Conference on Next Generation Internet Design and Engineering, Valencia, SPAIN 2

BME - TMIT BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICSDEPARTMENT OF TELECOMMUNICATIONS AND MEDIA INFORMATICS

Triple-Play in Metro Ethernet Network

Data

TV + Set Top Box Home Gateway

Video

Head End

VoD

VoIP

GW

Access Node

Switch

Switch

Switch

SwitchEdge node

Edge node

Service Providers’ NetworksMetropolitan NetworkLocal Access / First mileCustomers’ Home Net.

» Three different services on a single infrastructure» High Speed Internet (HSI)» Voice over IP (VoIP)» Video service (IPTV, iVoD)



» Ethernet is the most dominating LAN technology» Cheap equipment + high speed (up to 10 Gbps)

Ethernet in Metro Networks

Switch Edge nodeAccess Multiplexer Switch SwitchSwitch

Metro Core

RS CS TR RD TD CDTALK / DATA

TALK

CableModem1 2 3

4 5 6

7 8 9

* 8 #

Metro Access

First MileHome Network CoreMetro Network

» Introduce Ethernet into the Metro network (Metro Ethernet Forum): » consistent network platform

» Ethernet should be Carrier Grade:» Traffic and User separationTraffic and User separation ~ Virtual LANs» QoSQoS ~ 8 traffic classes » ReliabilityReliability ~ Rapid Spanning Tree Protocol» ScalabilityScalability ~ MAC-in-MAC and Q-in-Q» Operation, Administration ManagementOperation, Administration Management



Routing in Ethernet: Spanning Trees Protocols (STP)

» MORE VLAN based spanning trees» Multiple spanning tree

instances» Each tree runs a separate

Rapid STP instance» 1 VLAN 1 tree

Bridge D

Bridge A

Bridge B

Bridge

Bridge

Bridge

Bridge

Bridge

Bridge C

Root II.Root I.

» By default tree spanning is “Topology-Driven”:» Port costs based on topology and link capacities

» Costs can be set manually (to obtain desired trees)

» Spanning Trees form loop-free logical topologies » Their shape influenced by Port Costs» Provide restoration



Resource Management Architecture

» TE-pipe» Runs between access and

edge nodes» pre-provisioned resources» Per Service

» AN & EN» Enforcing traffic via

» Policing » Shaping

» Network Management Entity» Manages the resources» Performs CAC based on

service datas and QoS.» Configures network elements

(e.g., SNMP)

Switch

Switch

SwitchModem

Modem

Switch

Switch

Switch

Network Management Entity

Computer

Telephone

TV and Set Top Box

Access Node

Access Node

TE pipe

Edge node

Edge node



QoS Model

» Priority based scheduling:» Lower priority traffic is not served until there is higher priority traffic

in the queue.

» To ensure low delay for each QoS class:amount of higher priority traffic should be limited for each link

» Static global limits are defined for each class

» The method of how to determine these limits is out of scope.

Class ID Provided service

BW ratio

1 VoIP 0.1

2 IPTV 0.2

3 - -

4 HSI remaining



IPTV: Multicast in Metro Ethernet

» Efficient distribution of Video needs multicast

» Dynamic Multicast» Ethernet switches “snoops” IGMP messages» Decides on which ports sends the packet out.

» Manual Filtering» VLAN are for restricting Broadcast Domains» Shaping the VLAN to Multicast-trees

» Assumed method» Forming P2MP Pipes ~ VLANs» Carrying more MC tree» IGMP snooping can be also used



HSI: Statistical Multiplexing

» Traffic of individual users highly varies» Considering it at PIPE dimensioning

» Aggregation of these flows still fluctuates

» Guèrin's model assumed» Variances of Flows have

to be estimated» Flows ~ Independents & Normal Distribution

» TE pipes are described: (Mean Rate; Peak Rate)

n

i

n

iiiaggr mBW

1 1

2



On the Optimal Configuration of Metro Ethernet for Triple Play

Proposed Method and Simulation Results



Problem Formulation

» Input parameters:» Topology » QoS model» Static Traffic Matrices for each service» Tree Instances

» The proposed method» Defines uni/multicast pipes for demands,» Spans the tree instances and» Assign the pipes for the tree instances

» Integer Linear Model was presented for the basic problem, but it does not deals with» statistical multiplexing» multicasting



Proposed Heuristic Method

» Decomposes the problem to

» Sequential allocation of pipes AND appending them to a tree instances.

» Demand ordering problem

» In each iteration random selection between:» Allocation of NEW pipe» Remove an existing tree



Case Study» Assumed dual homing based topology

» Services» VoIP

» Unicast + symmetric PIPEs» No statistical mux assumed.» 10% of total traffic

» Video» Multicast + asymmetric PIPEs» Medium traffic variance (PMR ~1.2)» 30% of total traffic

» HSI» Unicast + asymmetric PIPEs» Large traffic variance (PMR ~ 2.0)» 60% of total traffic



Traffic Model

» Demand sizes based on Gaussian distribution» PEAK rate: Total traffic level x Service Ratio » MEAN rate: PEAK rate / PMR

» VoIP and HSI : separate PIPEs for each AN—EN pair

» IPTV: 1 multicast PIPE for each EN.

» Performance descriptor: ACHIEVABLE THROUGHPUT» Determined via binary search of Total traffic level



The effects of Statistic Multiplexing

Same throughput –

less resources

20% more throughput achieved



Notes on scalability

» „OFF-LINE” configuration method» No strict time constraints

» Scalability still important» On larger networks » Perform Dynamic TE

» The proposed method iterative + polynomial steps» Finds solutions within a minutewithin a minute in the Test Case» Needs 100 rounds to find the solutions

» For 1000 and 10000 rounds only a slight increase of performance…

» Recent simulation on larger networks also show its scalability



Conclusion

» To provide Triple-Play QoS aware architecture is needed

» To decrease costs Ethernet is a good choice

» We propose» An efficient algorithm for off-line configuration» Deals with priority based QoS» Multicast» Exploit the effects of Statistical Multiplexing

» Its performance is presented on a test case



Thank you for your attention

Date post:	23-Dec-2015
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