Transcript ETE Framework for QoS guarantee in Heterogeneous Wired

ETE Framework for QoS guarantee
in Heterogeneous Wired-cum-Wireless Networks
(cont.)
홍석준
2007.5.29
ETE reservation setup procedure
(Downlink-Sender is in wired network)
④
RSVP_ResvCon
f①
RSVP_Path
R
④
RSVP_ResvCon
f①
RSVP_Path
S
Access
Point
③
③
RSVP_Resv
RSVP_Resv
Intermediat
e
/WBM
Routers
② Check Available BW in WLAN
and whether Outgoing Link
supports the request rate. If
satisfies, send ③Otherwise give
up reservation
After ③,
RSVP_ResvConf has not been
received after a certain time
period. Frees the BW allocated
ETE reservation setup procedure
(Uplink-Sender is in wireless network)
③ RSVP_Resv
(RSVP_ResvT
ear)
S
④
WRESV_RESPONS
E
①
WRESV_REQUES
T
③ RSVP_Resv
(RSVP_ResvT
ear)
RSVP_Path
Err
RSVP_Path
Err
② RSVP_Path
(RSVP_PathT
ear)
If flow reservation in the
wired network is
successful, then AP
received RSVP_Resv.
Otherwise, AP received
RSVP_ResvTear
R
② RSVP_Path
(RSVP_PathT
ear)
④
④
RSVP_ResvConf RSVP_ResvConf
After ①, AP maps the necessary information in
WRESV_REQUEST and sends RSVP_Path to wired
receiver
After ③, AP (WBM) enforces the admission control,
If Successful, AP maps the necessary information in
RSVP_Resv and sends WRESV_RESPONSE to
If AP receive Error
message, after some
time, AP send
PathTear message to
remove all path
states.
Optimization (for Uplink flow)
S
WRESV_REQUES
WBM
T checks if the flow can be admitted immediately.
If the reservation request cannot be supported in the
WLAN,
Then it is not necessary to send RSVP_Path to the
Receiver.
R
Support of multicast session
1. All Receivers are in the wired
network
(1) Sender is also in the wired
network
R
S
R
R
Multicast session can be taken care by
RSVP/SBM
Support of multicast session
1. All Receivers are in the wired
network
(2) Sender is in the wireless
network
R
R
S
Proxy
R
All reservation request from Receiver are merged at AP
The WBM enforces admission control according to merged reservation
message
Support of multicast session
2. All Receivers are in the wireless
network
(1) Sender is in the wired
network
R
R
S
R
AP records the list of receivers subscribing the same multicast
sessions.
For each such session, AP only reserves bandwidth (if admitted)
for one subscriber.
When AP receives data packets from the sender (the multicast
session has been reserved successfully), AP simply piggybacks
the receiver list in the data packet and broadcasts it.
Support of multicast session
2. All Receivers are in the wireless
network
(2) Sender is also in the wireless
network
R
R
S
R
This multicast session can be supported efficiently with only
one broadcast of each packet from the sender.
The list of the receivers should be piggybacked with the broadcast
message so that wireless stations that are not in the list will discard
the packet.
QoS support of node mobility
Forward data
Forward request
(with QoS requirment)
Accept/reject
Home
AP
Send request
Target
AP
data
Associatio
n
(with Target
AP)
MH
MH
QoS re-negotiation
• In wireless networks, due to the high channel
error rate and node mobility, the link
condition may not be very stable, leading to
varying available channel bandwidth.
• In this case, it is possible that the bandwidth
requirement of admitted flows can no longer
be satisfied.
• Therefore, QoS re-negotiation is necessary.
QoS re-negotiation
• when AP notices that available
bandwidth decreases to zero, it looks
up the flow reservation list, chooses
several most recently initiated flows as
candidates, and then requests them to
handoff.
• When a MH receives a handoff request,
MH follow handoff procedure.
QoS re-negotiation
• when AP notices that available
bandwidth decreases to zero, it looks
up the flow reservation list, chooses
several most recently initiated flows as
candidates, and then requests them to
handoff.
• When a MH receives a handoff request,
MH follow handoff procedure.
QoS re-negotiation
• If handoff succeeds at one MH, AP will
be notified and it then tells other MHs to
give up handoff.
• If none of the MHs is able to handoff to
neighboring cells, AP will request the
sender of the most recently initiated
flow to drop the flow.
QoS re-negotiation
•
AP removes the flow under the two situation
1) If the flow sender is in wired network, AP sends a
RSVP_ResvTear to the sender to drop the flow in
wired nodes
2) If the flow sender is in wireless LAN, AP sends a
notification to the corresponding MH, which
silently gives up the data transmission of the flow.
Message mapping at access point
• In WRESV, the admission control decision is made at
the MAC layer, not the network layer.
• Therefore, message mapping is necessary for correct
operations of the protocol.
• Since the wireless part and wired part are connected
at the IP layer, layer interaction only exists between
wireless IP layer and IEEE 802.11 MAC layer in order
for both parts to be aware of QoS characteristics of
flows to be reserved.
• Therefore, standing in the center of the functionalities
of AP is the cross-layer interaction, i.e., message
mapping between IP layer and MAC layer in wireless
network.
Message mapping at access point
Performance evaluation
Conclusion
• The proposed integration scheme
considers both features of RSVP as well
as the characteristic of wireless medium,
thereby efficiently supporting multicast
session as well as node mobility.
• With cross-layer interaction, overhead
of message mapping at the boundary of
the wired and wireless network is
significantly reduced.