QoS Provisioning in IP-based Broadband Wireless Mobile Networks

1. Workshop on Broadband Wireless Ad-Hoc Networks and Services, 12th - 13th September 2002, ETSI, Sophia Antipolis, France QoS Provisioning in IP-based Broadband Wireless Mobile Networks A. H. Aghvami and Bongkyo Moon Centre for Telecommunications Research King’s College London E-mail: {hamid.aghvami, bongkyo.moon}@kcl.ac.uk

2. 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

3. RSVP Issues under IP micro-mobility (1) 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

4. RSVP Issues under IP micro-mobility (2) • 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

5. RSVP-enabled router in IP micro mobility

6. Mobile node (MN) moves into soft handoff zone No Pilot signal strength from a new BS ≥ TRSVP Yes Yes No MN is a sender ? Send RSVP PATH message along the new BS toward GW Send a route update message along the new BS toward GW Mobile node keeps on-going flow without special action Determine the location of a crossover router (CR) in IP mobility networks Yes No RSVP daemon on the CR immediately triggers a PATH message toward the MN RSVP daemon on the CR immediately sends an RESV message toward the MN QoS disruption QoS guaranteed BS receives an RESV message, and then executes resource allocation algorithm over wireless link to reserve resource MN sends RESV message toward the intended receiver CR is a receiver ? RSVP reservation is completed within threshold time ? No Yes Soft handoff initiates with RSVP reservation along the new path by switching RSVP branch path successfully Proposed RSVP-based QoS Mechanism

7. RSVP Branch Path Rerouting under IP Micro Mobility Protocol

8. Determination of Crossover Router • 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 whendetecting any changes to the stored PATH state or receiving a PCN message from the underlying routing daemon.

9. Rerouting of Branch Path at CR • - 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

10. Internet Gateway (GW) Crossover Router (CR) CR MN RSVP Branch Path Rerouting in a Tree

11. MN MN AR (BS) AR (BS) CR CR GW GW - MN is a sender route update route update & PATH route update route update & PATH route update route update PATH RESV PATH RESV RESV RESV - MN is a receiver RSVP Path Rerouting Signaling at CR

12. Seamless Switching of RSVP Branch Path under IP Micro Mobility Protocol

13. Access Router B Access Router A Soft handoff Initiation with RSVP Reservation along the new Path RSVP Reservation Request along the new Path via BS ‘B’ Pilot Strength Soft Handoff Zone TADD TRSVP TDROP Handoff Drop Timer RSVP Path Preparation Zone (S) Distance RSVP Path Reservation for Soft Handoff

14. Original RSVP reservation path of the flow Branch path added newly during soft handoff CN Internet GW CR BS ‘A’ BS ‘B’ MN Switching of RSVP Branch Path (1)

15. Original RSVP reservation path of the flow CN Branch path added newly during soft handoff Gateway Router IP Micro Mobility Networks Crossover Router Access Router Switching of RSVP Branch Path (2)

16. Probability of Service Disruption (1) Various TRSVP under V =9.0 m/s and high load.

17. Probability of Service Disruption (2) MN’s various velocity under TRSVP = -13.4 dB and high load

18. Probability of Service Disruption (3) Various load condition under V =10.0 m/s and TRSVP = -13.3 dB

19. Mean Number of Lost Packets Various TRSVP under V =9.0 m/s, high load and 1 Mbps data rate

20. 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.