nov. 19, 2007 chen-bin kuo (20077202) and young j. won (20063292) dpnm, postech

Paper Presentation – CS 702, Fall 2007 DPNM Lab.

“On the Optimal Configuration of Metro Ethernet for

Triple Play”

Andras Kern, Istvan Moldovan, and Tibor Cinkler

Budapest University of Technology and Economics, Hungary

Appeared in IEEE 2nd Conference on Next Generation Internet Design and

Engineering (NGI), pp. 334-341, April 3-5, 2006.

“On the Optimal Configuration of Metro Ethernet for

Triple Play”

Andras Kern, Istvan Moldovan, and Tibor Cinkler

Budapest University of Technology and Economics, Hungary

Appeared in IEEE 2nd Conference on Next Generation Internet Design and

Engineering (NGI), pp. 334-341, April 3-5, 2006.

Nov. 19, 2007

Chen-bin Kuo (20077202) and Young J. Won (20063292)

DPNM, POSTECHEmail: {kuo, yjwon}@postech.ac.kr

Nov. 19, 2007

Chen-bin Kuo (20077202) and Young J. Won (20063292)

DPNM, POSTECHEmail: {kuo, yjwon}@postech.ac.kr

(2) DPNM Lab.Paper Presentation – CS 702, Fall 2007

IntroductionThis paper focuses on provisioning of the Ethernet

aggregation to support Triple Play services

What’s this about?- About QoS provision in Metro Ethernet- Traffic representation models for triple play components- Configuration method of VLANs in Metro Ethernet for triple

play


Triple Play in Metro NetworksPromising Technology: Metro Ethernet

- IEEE 802.1Q QoS standard, 8 QoS classes to the Ethernet- Scalability by segmenting the network into independent

Virtual LANs (VLANs), representing a different broadcast domain

802.1D Spanning Tree Protocol (STP)- Defines a loop-free logical forwarding topology over the

meshed physical topology- Rapid Spanning Tree Protocol (RSTP) decreases the

failover time to a few seconds

Multiple Spanning Tree Protocol (MSTP)- The VLANs are uniquely associated to the MSTIs inside a

region while one MSTI aggregates the traffic of more VLANs


QoS Provisioning in Metro Ethernet Real Time (RT), Streaming, Transactional, and Best Effort (BE)

- Diffserv, compatibility with TIU-T and 3GPP

- 802.1Q compliant switches

Hypothetical assumption: 10% for RT, 20% for Streaming, 30% for Transactional classes- VoIP = RT

- IPTV = Streaming

- HIS = BE

Acronyms- Network Management Entity (NME)

- Policy Enforcement Points (PEPs)

- Policy Decision Point (PDP)

- High Speed Internet Access (HSI)


Network Architecture for Triple Play

Policy based management model- A policy is a set of rules controlling how to access to and set the

priorities for the use of resources

The pipe for VoIP is a point-to-point bidirectional pipe

The Video service uses an unidirectional multicast pipe- While the HIS service is a point-to-point pipe with asymmetric

allocated capacity


VoIP Service: Call Level Multiplexing The well-known Erlang-B formula determines the

number of simultaneous calls required to serve a fixed size of population with a defined blocking probability threshold- To provide an acceptable bound for call blocking probability

Then, the bandwidth of a VoIP TE-pipe can be known- Based on the number of parallel calls- Based on the bandwidth requirement of the assumed codec


IPTV Service: Multicast in Metro Ethernet

Manual multicast filters based on VLAN or Ethernet multicast address- Service providers can configure Ethernet switches manually

with a multicast filter

Dynamic multicast forwarding:

Ethernet switches can also listen to the IGMP Join messages used by receivers to query for a multicast source- Or the use of GMRP (GARP Multicast Registration Protocol)

for interworking with IGMP, a few vendors


HSI Service: Statistical Multiplexing (1/2)It does not exploit the provided bandwidth

- The bitrates of typical internet traffic generated by home users varies significantly

Related Works- F. Kelly [10] presented the theoretical basics of statistical

multiplexing aware dimensioning considering different traffic models

- S. Floyd [11] proposed a simple method to calculate the effective bandwidth for aggregation of independent traffic flows based on the Hoeffding bound

Large number of individual flows, the ratio of mean and peak rates are close to zero

- Suppose the individual traffic flows are independent and the aggregation has Gaussian distribution

Guerin [12]


HSI Service: Statistical Multiplexing (2/2)

Guerin [12] continues, as in (1)- A simple, effective model- Mean bit rates (m)- Standard deviation epsilon of the aggregation considered alpha- Bandwidth overflow probability can be adjusted by alpha

Deterministic multiplexing- The allocated capacity is the sum of the peak rates of the

individual flows


Proposed Configuration MethodA method for configuration of VLANs taking into

account the requirements of all three services

The author’s previous work focused on providing a formal model dealing with unicast TE pipes- To minimize the allocation of network resources for a set of

traffic demands and the number of used MSTIs- Presented an Integer Linear Program (ILP) formulation with

scalability problems

Heuristics for two subtasks- Pipe or VLAN routing and covering them with trees- Heuristic is needed: ILP model cannot deal with the non-

linearity by the statistical multiplexing


Proposed Heuristic Algorithm (1/2)Inputs to the algorithm

- The topologies of the trees are combined from paths of the assigned VLANs

- QoS constraints and the demands

The method decomposes the problem to sequential search of VLAN routes and assignment to MSTIs- It adopts the Simulated Allocation (SAL) metaheuristic

Allocation operator- Randomly select one VLAN among the unassigned ones- Fit the VLAN to the already defined MSTIs- Otherwise, create a new MSTI and assigned to the VLAN


Proposed Heuristic Algorithm (2/2)For unicast VLANs (VoIP and HSI) a single path is

sought from the access to the edge node

For multicast VLANs, the tree is determined by calculating independent shortest paths from each accesses to the sole target one after the other

Disconnection process- It selects the tree having the least assigned VLANs, and

remove it


Case Study (1/2)“Traffic drive” configuration method produces high

throughput gain in the topologies of practical interest [6]

The sizes of the demands depend on the overall throughput (OT) and the service ratio (SR) parameters- OT is responsible for the system-wide throughput- SR defines how to distribute the traffic between the classes

Assuming- VoIP traffic is 10%, video broadcast traffic is 30%, and the

best effort internet is 60%- The exact size of a demand is generated randomly with

Gaussian distribution


Case Study (2/2)Taking the variance of the traffic into account ratios

of the mean and peak rates- PMR = b_peak / b_mean- VoIP = 1.0, Video = 1.2, Internet = 2.0

Evaluation of Results- Figure depicts the allocated capacities (or network load)- Considering statistical multiplexing, 20% higher throughput

can be achieved

Considering statistical multiplexing influences the paths calculated for VLANs- Statistical multiplexing becomes the part of the optimization

task


ConclusionsDue to cost considerations the Ethernet becomes

the most cost effective solution for regional and metropolitan networks

Presented a QoS service architecture over Metropolitan Ethernet networks- Based on traffic engineering logical channels (or pipes)

Main contributions- Propose an efficient algorithm for off-line configuration of

metro Ethernet networks for triple play- Multicast VLAN based trees to provide video broadcast

service- The gain of statistical multiplexing


Questions ?

nov. 19, 2007 chen-bin kuo (20077202) and young j. won (20063292) dpnm, postech

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