Reliable Multicast Congestion Control

1
Reliable Multicast Congestion Control PGMCC
2
PGMCC
Sender sends packet
Acker sends ACK
3
PGMCC
Sender
Receiver
Acker
Data
NACK
ACK
Sender sends next packet
Packet lost by one receiver
Receiver sends NACK and Acker sends ACK
If the NACK is from a receiver worse than Acker,
then it is designated as the new Acker
4
PGMCC
Sender
Receiver
Acker
Data
NACK
ACK
Sender sends next Packet
New Acker sends ACK
5
Unnecessary Starvation
Sender sends packet
Acker leaves
Sender waits until timeout (unnecessary
starvation)
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NAK Suppression
TS
TR
R
R
R
Congested Link
PS
PR1
PR2
TS TCP Sender TR TCP Receiver PS
PGMCC Sender PR PGMCC Receiver R Router
NACK
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Mobile IP
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Basic Entities
FA
HA
MN
Internet
HA Home Agent
FA Foreign Agent
MN Mobile Node CN Correspondent
Node
CN
9
Overview
FA
HA
MN
Internet
Normal Delivery of packets
Data Packet
CN
10
.. Overview
FA
HA
Tunnel
Internet
Tunnel formed between HA and FA
CN
11
Basic Mechanisms

• Movement Detection
• Agent discovery
• Registration
• MN registers with FA
• FA registers with HA
• Tunneling-DeTunneling
• De-Registration

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NormalMode,InHA,NoMobileNode
Initial State
FA
HA
Internet
CN
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NormalMode,InHA,NoMobileNode
AdvertisementTimer(HA)_exp
NormalMode,DiscoverAgent,NoMobileNode
Solicitation
NormalMode,DiscoverAgent,SendAd
Advertisement
NormalMode,RegisterMN,SendAd
RegisterReq(mn-fa)
FA
HA
Tunnel, InFA, DeTunnel
Advertisement
RegisterRequest
Internet
AdvertisementTimer(ha) Expires
CN
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Error ScenarioLoss of registration grant
Tunnel, RegisterMn, RegisterFA
Tunnel, RegisterMN, DeTunnel
Tunnel, InFA, DeTunnel
Tunnel, RegisterMN, DeTunnel
Leads to Blackholes
Recovery Time Request Retransmission timer
Registration Mechanism
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Error ScenarioCrash of HA
Tunnel, InFA, DeTunnel
Crash(HA)
Empty, InFA, DeTunnel
Incorrect State no home agent
Packets Destined for MN are never delivered to it
Unrecoverable if hard crash assumed
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Wireless MAC 802.11
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Notations
Carrier sensed as Idle
A
A is transmitting Data
Collision
Node States
A
A is transmitting Request To Send (RTS)
A
A is transmitting Clear To Send (CTS)
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Normal Scenario 802.11No loss, static nodes
Gi j, k, l Gj i, k, l, m
Idle
ni
Idle
k
Idle
Idle
i
j
Idle
l
Idle
m
GFSM start
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Normal Scenario 802.11No loss, static nodes
Pkti,j
Idle
ni
Idle
k
Idle
Idle
i
j
Idle
l
Idle
m
GFSM i wants to send to j
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Normal Scenario 802.11No loss, static nodes
RTSi,j,Gi
Idle
ni
Idle
k
Tx
Idle
i
j
Idle
l
Idle
m
GFSM i sends RTS to j
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Normal Scenario 802.11No loss, static nodes
RTSi,j,Gi
Idle
ni
Defer
k
WFCTS
Tx
i
j
Defer
l
Idle
m
GFSM nodes in Gi receives RTS
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Normal Scenario 802.11No loss, static nodes
CTSj,i,Gj
Idle
ni
Defer
k
WFCTS
Tx
i
j
Defer
l
Idle
m
GFSM j sends CTS to i
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Normal Scenario 802.11No loss, static nodes
CTSj,i,Gj
Idle
ni
Defer
k
WFDATA
Tx
i
j
Defer
l
Defer
m
GFSM nodes in Gj receives CTS
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Normal Scenario 802.11No loss, static nodes
Datai,j,Gi
Idle
ni
Defer
k
WFDATA
Tx
i
j
Defer
l
Defer
m
GFSM i sends Data to j
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Normal Scenario 802.11No loss, static nodes
Datai,j,Gi
Idle
ni
Defer
k
WFACK
Tx
i
j
Defer
l
Defer
m
GFSM nodes in Gi receives Data
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Normal Scenario 802.11No loss, static nodes
ACKj,i,Gj
Idle
ni
Defer
k
WFACK
Tx
i
j
Defer
l
Defer
m
GFSM j sends ACK to i
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Normal Scenario 802.11No loss, static nodes
ACKj,i,Gj
Idle
ni
Defer
k
Idle
Idle
i
j
Defer
l
Defer
m
GFSM nodes in Gi receives ACK
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Normal Scenario 802.11No loss, static nodes
Idle
ni
Idle
k
Idle
Idle
i
j
Idle
l
Idle
m
GFSM end
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An Error Scenario 802.11 No loss, static nodes
Pkti,j
Idle
ni
Idle
k
Idle
Defer
i
j
Idle
l
Defer
m
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An Error Scenario 802.11 No loss, static nodes
RTSi,j,Gi
Idle
ni
Idle
k
Defer
Tx
i
j
Idle
l
Defer
m
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An Error Scenario 802.11 No loss, static nodes
RTSi,j,Gi
Idle
ni
Defer
k
Defer
Tx
i
j
Defer
l
Defer
m
Node j does not reply to RTSi,j,Gi Unnecessary
defer by all nodes in Gi in 802.11
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A Scenario of Worst Case Performance 802.11
i
x
j
k
l
i
Mobility rate of the node that leads to
maximum collision gt Worst case mobility scenario
with respect to collision
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Topology Generation for MACAW
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Topology Generation for MACAW
RTS-CTS Collision
A
D
C
B
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RTS-CTS Collision (contd..)
Due to RTS-CTS collision B is unaware of the
successful RTS-CTS communication between C and D
A
D
C
B
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RTS-DS Collision
A
D
C
B
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RTS-DS Collision (contd..)
Due to RTS-DS collision B is unaware of the
successful RTS-CTS communication between C and D
A
D
C
B
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Data-Data Collision
A
D
C
B
Messages which are heard, but no action is taken