PRESENTED BYA. B. C.

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User Oriented Regional Registration-Based Mobile

Multicast ServiceManagement in Mobile IP Networks

Ing-Ray Chen and Ding-Chau Wang

Multicasting2

According to Wikipedia:

“IP multicast is a technique for one-to-many communication over an IP infrastructure in a network. It scales to a larger receiver population by not requiring prior knowledge of who or how many receivers there are. Multicast uses network infrastructure efficiently by requiring the source to send a packet only once, even if it needs to be delivered to a large number of receivers.”

Multicasting is not BROADCASTING though

Group management is a key attribute of multicasting

Uses of Multicasting3

Video/Voice conferencing

Database replication

IP television

Bulk Software updates to subscribers over the network/intranet

How is Multicasting achieved?4

IGMP – Internet Group Management Protocol

Multicast distribution trees

Use of class D addresses 224.0.0.0 – 239.255.255.255

Essentially Multicasting boils down to sending and receiving from a common address.

Multicasting challenges within Mobile IP

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Dynamic Topology

No fixed underlying infrastructure makes the creation of Multicast distribution tree difficult.

The router will keep on asking the question:“How do I send this message to the group member that is not within my transmission range???”

Dynamic Group Membership

Changing infrastructure compromises the “common” destination that the publisher and subscribers rely upon for data dissemination

So what we need is URRMoM…a.k.a “Your Mom”

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It actually stands for user-oriented regional registration based mobile multicast protocol

Supratik will explain why “Your MoM” does things way better than some other “MoM”s

Fenye will explain SPNP performance model to quantify the claims in the paper made about “Your MoM”

Reghu will present the analytical and simulation results followed by the conclusions

Let the best “MoM” win!!!!

Some background on “MoM”7

Two basic schemes were originally proposed by the IETF…

Remote Subscription Mobile Host always needs to subscribe to its multicast group

when it enters or changes a foreign networks. This essentially means that the current local router of the

Mobile host is made part of the Group subscription tree• Pros – Optimal trees are constructed for message delivery• Cons – Too many reconstructions of the delivery tree.

Bi-directional tunneling Multicast delivery tree stays the same since the Home Agent

of the mobile host is responsible for sending the message out to the Mobile Host…• Pros – The Multicast Delivery tree stays the same even though source and

destination nodes hop across networks• Cons – Routing path is not optimal and Foreign agents may receive

duplicate packets

“Your MoM”??8

Is going to combine the advantages of Remote Subscription with Bi-directional tunneling, without the disadvantages…

Lets look at some proposed ways...

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Local registration to support Multicast services Usage of Multicast Agents(MA) mMom

- A hybrid approach of Bi-directional tunneling and Remote Subscription- If Mobile Host is highly mobile BT is used otherwise RS is used- The FA makes the determination whther MH is mobile or immobileCons – Does not factor in co-located care of address in MIP(???)

RBMoM- Uses MMA to tunnel packets to the FA serving the MH- Current MMA information is stored in the MH’s HA- If MH is out of MMA range, MMA handoff occurs- Agent Table updates at FA to know which MMAs are around- MH can look at Agent table to figure out the nearest MMA.Cons – Excessive Communication Overhead

URRMOM10

Design Goals of URRMoM:

No overhead of maintaining Agent tables

Minimize network traffic generated due to Multicast packet delivery and Multicast tree maintenance

Simplicity, Scalability and Efficiency

Key Players of URRMoM11

Mobile Multicast Agents (MMA)• Tunneling Multicast Packets to foreign agents• Maintain knowledge about the regional service area (number of subnets covered)• Unsubscribe from the Multicast tree

Mobile Host (MH)• Maintains a counter to record the number of subnets crossed within the service area

of an MMA• Checks if the Foreign Agent of the subnet is part of the Multicast group• Checks if a counter has reached the regional area size• Subscribes to a new MMA

Foreign Agent (FA)• Receives tunneled messages from an MMA• Forward the tunneled messages to the Mobile host• Act as an MMA for Mobile Hosts

URRMoM Algorithm12

MH moves across subnets

For every move the MH counter increases by one

If the MH encounters a FA within a subnet which is an MMA for other Mobile Hosts, the MH will change its regional MMA and set the counter to zero

If the MH moves across the regional service area, the new FA becomes the MH’s new MMA. The FA will subscribe to the Multicast tree in case its not an MMA originally.

When the MMA is no longer serving any MHs, it will unsubscribe itself from the multicast tree

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Fig. 1 a Counter reset due to new FA being a MMA. b Counter reset due to service area handoff

Regional Service Area14

The Mobile Host can make the determination of an optimal service area that will minimize the network traffic overhead. This optimal service area (R) will be compared against the current value of the MH counter to make MMA handoff decisions

The Mobile Host can guage the optimal service area based on the following parameters:• Mobility of Mobile Hosts• Number of Mobile Hosts• Size of the network • Topology of the network

Performance Model15

A multicast group with a single source; The source is a fixed host; The multicast group membership does not change

dynamically but mobile members may roam dynamically.

M group membersn by n mesh network

Performance Model16

MH’s residence time in a FA is exponentially distributed with parameters μ. (mobility rate is μ)

MH’s expected residence time in one FA is 1/μ. MH’s expected residence time in n2-1 FAs is n2-1/μ. Thus, MH’s inter-arrival time to any FA is n2-1/μ.

The arrival rate of a single MH to any FA is λ:

Performance Model17

Arrival-departure process of M members with respect to a FA:

Probability that a MMA does not contain any group member:

The average number of members being resided under one FA:

Performance Model18

Every FA is capable of acting as a MMA. Every MH keeps a counter to record number of FAs it has

crossed from its current MMA. A MH sets current FA as its new MMA when:

(1) current FA is a MMA; (2) counter value equals to threshold R. (R is per-MH based depending on

it service and mobility characteristics.) Each MMA on average covers R subnets, group

members. Thus, there are roughly MMAs in the system. The probability that a FA (a MH just enters) is a MMA,

denoted by PMMA:

Performance Model19

Performance model for describing a MH’s behavior

Performance Model20

We aim to find per-MH based optimal service area R, such that network traffic cost per time unit is minimized.

The optimal R is per-MH based, depending on MH’s service-to-mobility ratio.

Multicast group management (tree maintenance) cost, will decrease as R

increases

Tunneling (multicast packet delivery) cost, will

increase as R increases

Performance Model21

Multicast tree maintenance per time unit:Per-hop communication cost

Average number of hops between MMA

and source

Tree subscription /

un-subscription rate

Tree un-subscription rate

Tree subscription rate

Performance Model22

Multicast packet delivery per time unit:Per-hop communication

costMulticast packets

delivery rate

Hops from source to MMAs

Hops from MMAs to MHs

Cost vs. R (varying n)23

M=100, τ=0.025s, λp=10, β=15, μ = 0.00167Optimal service area size minimized

Cost vs. R (varying MHs)24

8x8 Mesh network As M increases, optimal R decreases – multicast packet delivery cost

dominates multicast tree maintenance cost

Effect of distance b/w source and MMA

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When β increases, the optimal range R increases Higher the disatnce, higher the maintenance cost – system prefers to have a larger

service area to reduce rate of tree subscription/un-subscription operations

• M = 100

Comparison – Maintenance Cost

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URRMoM always produces the least amount of network traffic compared with RS and RBMoM.

Comparison – Control Message Overhead

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Comparison – Transmission Delay28

• URRMoM performs comparably with RBMoM since both use the optimizing R values

• Basic RS scheme performs the best in terms of packet delay - at the expense of the much higher maintenance cost and control message overhead

SMPL Simulation – Cost vs. R for varying m

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SMPL Simulation – Cost vs. R for varying n

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Conclusions31

Combines distinct performance advantages of remote subscription and bi-directional tunneling.

URRMoM has simpler system requirements and less computation complexity than RBMoM.