Transcript Reaction paper 2 PPT

By
Bhanu Reddy
Srinivas Madlapelli
Outline
 Introduction
 IEEE 802.11s standard
 Routing in WMNs
 Introduction to HWMP
 VoIP performance Comparison in 3 protocols
 Results
 Conclusion
 References
Introduction
 Now Wireless mesh networks are becoming critical
part of IP networks.
 Routing in WMN has strong impact on capacity to
support VoIP connections.
 Here we compare three routing protocols in IEEE
802.11s based WMN.
1.AODV
2.DSR
3.HWMP
IEEE 802.11 standard
 Widely accepted standard for Wireless Local Area
Network (WLANs)
 Because of its cost effective and its simple establishing
wireless network.
 In this context IEEE 802.11s group is designed to
establish new extension of IEEE 802.11.
 Multihop mesh networks techniques applied for
interconnection of APs together that can build
wireless connection to small-to-large scale WLANs.
Continues…….
 This implementation is based on existing PHY layer of
IEEE 802.11/a/b/g/n which are operating in 2.4-5 GHz
unlicensed spectrum frequency band.
 MAC layer supports multi radio/multichannel
operation. And MAC routing protocol, MAC layer
broadcast-multicast mechanism supports for extensive
auto-configurability.
 VoIP needs wide area wireless coverage for freedom of
roaming.
 For that tremendous works done on IEEE 802.11
capacity to support VoIP applications.
 And showed VoIP packet aggregation mechanism to
increase capacity of WMN to support many VoIP
connections.
 Also showed path selection(routing) in WMN has
strong impact on capacity to support VoIP
connections.
Routing in WMNs
 Routing in WMNs is depending on routing protocol.
 Mesh characteristics are different from MANET and
mesh traffic is predominantly forwarded to and from
wire-line gate way nodes by forming logical tree
structure.
 Many routing algorithms are proposed in WMN, by
either proposing new routing protocol or adopting
MANET routing protocol.
Introduction to HWMP
 HWMP is proposed by 802.11 group and is based on
radio metric.
 Routing metrics affects the network performance.
 Minimum weighted path selected by routing protocol
must have good performance on terms of high
throughput and low packet delay.
 IEEE 802.11s WMNs uses airtime link metrics for
calculation of link cost
HWMP
 HWMP is default protocol for IEEE 802.11s WMN.
 The word “Hybrid” refers it supports both reactive and
proactive routing.
 It supports two modes of operation depending on
configuration.
1. On demand
2. Proactive
VoIP performance comparison in
IEEE 802.11s
 Simulation model
To access capacity of each protocol they used Network
simulator 2.It consists 50 nodes establish VoIP
connections with each other has no background
traffic. Each node has 2Mbps link and simulation time
is 300 seconds, time period for each VoIP call is 20
seconds.
Results
Conclusion
 Simulation results show the advantages of using
HWMP over the other MANET protocols
 AODV are not very effective due to hop count metrics
 HWMP is effective because it addresses the
shortcomings.
References
[1] IEEE, Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications, IEEE Standard 802.11,
June 1999.
[2] IEEE, “Draft amendment: ESS mesh networking,” IEEE
P802.11s Draft 1.00, November 2006.
[3] IEEE 802.11e, Wireless LAN Medium Access Control
(MAC) Enhancements for Quality of service (QoS), final
802.11e standard, July 2005.
[4] L. Cai et al. “VoIP over WLAN: Voice capacity, admission
control, QoS, and MAC”, In International Journal of
Communication Systems 2006.
[5] P. Wang et al. “IEEE 802.11e Enhancement for Voice
Service”, In IEEE Wireless Communications magazine,
February 2006
Thank you………