QoS Provisioning in IP-based Broadband Wireless Mobile Networks

Workshop on Broadband Wireless Ad-Hoc Networks and Services, 12th - 13th September 2002,

ETSI, Sophia Antipolis, France

 A. H. Aghvami and Bongkyo Moon

Centre for Telecommunications Research

King’s College London

E-mail: {hamid.aghvami, bongkyo.moon}@kcl.ac.uk

Outline

RSVP under IP Micro Mobility Protocol

Proposed RSVP-based QoS Mechanism

RSVP Branch Path Rerouting Determination of Crossover Router under IP micro mobility

RSVP Branch Path Rerouting at Crossover Router (CR)

Seamless Switching of RSVP Branch Path RSVP Branch Path Reservation in advance for Soft Handoff

Switching of RSVP Branch Path for Soft Handoff

Results

Conclusions

Wireless Bandwidth Restrictions

- RSVP allows Internet real-time applications to reserve resources before they start transmitting data.

- Many RSVP flows cause a lot of control information over wireless link

- RSVP reservation refresh messages need not be sent as often on the wireless link

- Efficient wireless bandwidth management scheme is required

RSVP Issues under IP micro-mobility (1)

Mobility

- Whenever a MN performs a handoff, RSVP signaling process must be invoked immediately to discover the new path to the MN from the CN

- However, long resource reservation delay may occur during re-establishment of a flow after handoff under RSVP

- Service disruptions could occur in providing real-time services under RSVP and mobility.

- need to make resource reservations in advance along the paths to the neighboring BSs

RSVP Issues under IP micro-mobility (2)

RSVP-enabled router in IP micro mobility

RSVP-enabled Router

RSRR Interface

Forwarding database

Routing daemon

RSVP daemon

RSVP State Information

PATHRESV

DATA

PATHRESV

DATA

...

PATHRESV

DATA

PATHRESV

DATA

...RSVP-enabled Router

RSRR Interface

Forwarding databaseForwarding database

Routing daemonRouting daemon

RSVP daemonRSVP daemon

RSVP State Information

PATHRESV

DATA

PATHRESV

DATA

...

PATHRESV

DATA

PATHRESV

PATHRESV

DATADATA

PATHRESV

DATA

PATHRESV

PATHRESV

DATADATA

...

PATHRESV

DATA

PATHRESV

DATA

...

PATHRESV

PATHRESV

DATADATA

PATHRESV

PATHRESV

DATADATA

...

Mobile node (MN) moves into soft handoff zone

Pilot signal strength from a new BS ≥ TRSVP

Mobile node keeps on-going flow without special action

MN is a sender ?

Send RSVP PATH message along the new BS toward GW

Determine the location of a crossover router (CR) in IP mobility networks

CR is a receiver ?

Send a route update message along the new BS toward GW

RSVP daemon on the CR immediately sends an RESV message toward the MN

BS receives an RESV message, and then executes resource allocation algorithm over wireless link to reserve resource

RSVP daemon on the CR immediately triggers a PATH message toward the MN

MN sends RESV message toward the intended receiver

Yes

No

Yes

Yes

No

No

RSVP reservation is completed within threshold time ?

QoS disruption

QoS guaranteed

Soft handoff initiates with RSVP reservation along the new path by switching RSVP branch path successfully

Yes

No

Proposed RSVP-based QoS Mechanism

RSVP Branch Path RSVP Branch Path Rerouting under IP Rerouting under IP Micro Mobility ProtocolMicro Mobility Protocol

- In the case an MN is a sender, an RSVP PATH message

is sent by an MN after the route update is completed. - When the RSVP daemon on the CR receives an RSVP

PATH message after a mobility event, it immediately

sends an RSVP RESV message to an MN without

delivering to the original receiver.

- In the case an MN is a receiver, the RSVP daemon on

the CR can trigger an RSVP PATH message immediately

when detecting any changes to the stored PATH state or

receiving a PCN message from the underlying routing

daemon.

Determination of Crossover Router

- Having multiple hops for a RSVP connection => more links are utilized and this increases the network congestion and resource reservation failure

- shorter hops and circuit reuse should be considered during RSVP path rerouting

- RSVP path re-establishment time depends on the number of hops required in rerouting the RSVP partial branch path, a crossover router(CR) dependent.

- branch path rerouting at CR in tree topology guarantees the minimum path change and the shortest path

Rerouting of Branch Path at CR

RSVP Branch Path Rerouting in a Tree

Internet

Gateway (GW)

Crossover Router (CR)

MN

CR

RSVP Path Rerouting Signaling at CR

MN AR (BS) CR GW

route updateroute update

route update

PATHPATH

RESV

RESV

MN AR (BS) CR GW

route update &

PATH route update &

PATH route update

RESV

RESV

- MN is a sender

- MN is a receiver

Seamless Switching of Seamless Switching of RSVP Branch Path under RSVP Branch Path under IP Micro Mobility IP Micro Mobility ProtocolProtocol

Access Router A

Pilot Strength

TADD

TRSVP

TDROP

Distance

RSVP Reservation Request along the

new Path via BS ‘B’

Soft handoff Initiation with RSVP Reservation

along the new Path

RSVP Path Preparation Zone (S)

Access Router B

Soft Handoff Zone

Handoff Drop Timer

RSVP Path Reservation for Soft Handoff

CN

GW

MN

CR

Internet

BS ‘A’ BS ‘B’

Original RSVP reservation path of the flow

Branch path added newly during soft handoff

Switching of RSVP Branch Path (1)

IP Micro Mobility Networks

Original RSVP reservation path of the flow

Branch path added newly during soft handoff

Crossover Router

Gateway Router

Access Router

CN

Switching of RSVP Branch Path (2)

Number of Levels in a Tree

2 3 4 5

Pro

babi

lity

of

Ser

vice

Dis

rupt

ion

0.2

0.4

0.6

0.8

0.0

1.0TRSVP = -13.1 dB

TRSVP = -13.5 dB

TRSVP = -13.6 dB

TRSVP = -13.3 dB

Various TRSVP under V =9.0 m/s and high load.

Probability of Service Disruption (1)

Number of Levels in a Tree

2 3 4 5

Pro

babi

lity

of

Ser

vice

Dis

rupt

ion

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

V = 6 m/s

V = 8 m/s

V = 10 m/s

V =12 m/s

MN’s various velocity under TRSVP = -13.4 dB and high load

Probability of Service Disruption (2)

Number of Levels in a Tree

2 3 4 5

Pro

babi

lity

of

Ser

vice

Dis

rupt

ion

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Low Load

Medium Load

High Load

Various load condition under V =10.0 m/s and TRSVP = -13.3 dB

Probability of Service Disruption (3)

Number of Levels in a Tree

2 3 4 5

Mea

n N

umbe

r of

Los

t Pac

kets

0

5000

10000

15000

20000

25000

30000TRSVP = -13.1 dB

TRSVP = -13.5 dB

TRSVP = -13.3 dB

TRSVP = -13.6 dB

Various TRSVP under V =9.0 m/s, high load and 1 Mbps data rate

Mean Number of Lost Packets

Conclusions

The rerouting of the RSVP branch path at a crossover router is considered in order to minimize the resource reservation delay and the packet loss resulting from handoffs.

Seamless rerouting scheme of RSVP branch path for soft handoff was proposed in order to guarantee the QoS of on-going RSVP flows during handoff.

This scheme could provide QoS guarantee for RSVP flows under IP micro-mobility network.