Download An Overview of the Web over Wireless Group

An Overview of the Web over
Wireless Group
Web over Wireless Group
UC, Berkeley
Web over Wireless Group
Group
Prof. Pravin Varaiya
Researchers:
Dr. Anuj Puri
Baris Dundar
Graduate Students:
Mustafa Ergen
Sinem Coleri
Duke Lee
Xuanming Dong
Rahul Jain
Mohit Agarwal
Amit Mahajan
Under Graduate Students:
Jeff Ko
Yan Li
Web over Wireless Group
http://wow.eecs.berkeley.edu
Research Focus
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Cellular networks
Ad Hoc wireless networks
Sensor networks
Applications
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Web over Wireless Group
Cellular Networks
 Current Cellular newtorks
 Geographical area divided
into cells
 Base station (BS) in each
cell
 Primary traffic is voice
 What will future wireless
networks look like?
 Primary traffic is data
 Cellular + Wireless LANs
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Web over Wireless Group
Heterogeneous Wireless Networks
 802.11 Wireless
LANs
802.11 Hot
Spot Coverage
Wide Area
Cellular Coverage
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 Upto 50 Mbps
 Unlicensed spectrum
 Cheap and easy to
set up
 Hot spot coverage
with wireless LANs
 Mobility between
networks
 Applications
Web over Wireless Group
Ad Hoc Wireless Networks
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Wireless token ring
DSDV routing
Geographical routing
WTP
Sensor Networks
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Web over Wireless Group
Wireless Token Ring Protocol
 Multiple rings
 Station with token transmits
 Deterministic bounds on access time
 “Adjacent” rings transmit on different channels
 Basic operations of “join” and “leave” to allow mobility
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Web over Wireless Group
DSDV - Wireless Routers
Internet
Wireless
Router
Cheaper/better performance cellular
networks
Ad Hoc wireless networks
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Web over Wireless Group
Geographical Routing Algorithm
Geographical
network
 All nodes know their positions
 Packet for a destination postion
 Use geographical information in routing
 i.e, route to neighbor nearest to the destination
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Web over Wireless Group
Transport Layer (WTP)
 UDP: Connectionless but unreliable
 TCP: Connection oriented and reliable
 WTP: Connectionless and reliable
 Used by WAP (Wireless application protocol) as a
“transaction protocol” for cell phones
 Optimized for wireless links for short messages
Doesn’t use congestion control
Small WTP headers
 Message based protocol
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Web over Wireless Group
Network Architecture
Mobility
Management
Transport Layer
Network Layer
Data Link
MAC
Physical Layer
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Web over Wireless Group
TCP/UDP/WTP
Geographic routing,
DSDV, QOS, TBRF,
STARA
Token ring,
bluetooth
802.11, Seedex
OFDM
Mobility and Internetworking Among
Networks
802.11
Internet
Token
Ring
DSDV
Geographic
Routing
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Web over Wireless Group
Sensor
Networks
Technology
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Wireless Token Ring
DSDV routing
Geographical routing and WTP
Mobile IP
Fast Handoff
MEWLANA
Sensor Networks
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Web over Wireless Group
WIRELESS TOKEN
RING PROTOCOL
Web over Wireless Group
Introduction
7
7
1
5
5
4
1
 The Wireless Token Ring Protocol (WTRP) is a medium access control protocol
for wireless networks in mission critical systems.
 It supports quality of service in terms of bounded latency and reserved
bandwidth.
 The token passing defines the transmission order, and each token is forced to
give up the token after a specified amount of time.
 Each ring has unique ring id based on unique MAC address of one of the stations
of the ring. (The station is called the owner of the ring).
 When owner leaves the ring, another station elects itself to be the owner of the
ring.
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Web over Wireless Group
4
Descriptions (Operations)
Invite
Contend
Token
Token
Joining: Stations periodically invite other nodes to join the ring by broadcasting the available
resources left in the medium
1. SET_SUC C
A
B
C
2. SET_PRED A
F
E
D
Leaving: When B wants to leave, it requests A to connect to its successor, C. If A does not have
connection with C, then it connects to the next node in terms of the transmission order of the ring.
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Web over Wireless Group
Descriptions (Management)
1. Retransmit TOKEN
A
C
B
2. SET_PRED A
F
D
E
Ring Recovery Able to recover quickly by keeping information about topology of the ring,
recovers from multiple simultaneous faults by taking increasingly drastic actions
2
2
6
6
2
6
6
2
6
2
6
6
6
2
6
Token Recovery Multiple token is deleted using unique priority of token based on generation
sequence number and token ring address pair.
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Web over Wireless Group
WTRP Deliverables
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Web over Wireless Group
WTRP USER-SPACE
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Web over Wireless Group
WTRS-WTR Simulator
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Web over Wireless Group
Performance Analysis
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Web over Wireless Group
Performance Analysis
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Web over Wireless Group
DSDV Routing
Web over Wireless Group
DSDV Routing Protocol
Based on Bellman-Ford algorithm
Use sequence number to avoid loopforming and make convergence fast
The sequence number must be
originated by the destination node
There is a trade off between the
stability and the convergence speed of
the routing table
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Web over Wireless Group
System Architecture
DSDV Daemon
DSDV Router
Zebra Daemon
Socket Layer
RIB
Linux Kernel
TCP
UDP
Kernel Routing
Layer
ARP
IP
IEEE 802.11
Network Interface
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IEEE 802.11 MAC Layer
Web over Wireless Group
Events of DSDV Protocol
1.Timers
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Periodical updates (30-second)
Random offset timer (at most 30-second)
Timeout (30-second)
garbage-collection (120-second)
2.Input processing
 Request
 Response
1. response to a specific query
2. regular updates
3. triggered updates triggered by a metric change
3.Output Processing
 by input processing when a request is received
 by the periodical routing update
 by triggered updates caused by changed route metric
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Web over Wireless Group
Timers in DSDV
 Periodical updates (T)
 send the full routing table to the neighbors.
 Random offset timer (<T)
 suppress the triggered updates and avoid unnecessary
collisions on broadcast networks.
 Timeout (3*T)
 the routing entry is no longer valid if the TTL is zero.
However, it will be retained in the table for a short time
so that neighbors can be notified.
 garbage-collection (3*T)
 the route is deleted from the table and no longer
included in all updates with a metric of infinity.
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Web over Wireless Group
How does the DSDV Daemon work
DSDV_Daemon()
{
Detect network interfaces and copy required information;
Read configure file and initialize all variables and routing
table;
Create a UDP socket for DSDV routing messages;
Send hello message to all neighbors;
Install signal handlers for different kinds of timers;
Loop for events (select())
Different timers:
Input processing:
Output processing:
Other system events:
}
Loop end
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Web over Wireless Group
Geographical Routing
Web over Wireless Group
Overview
“Geographical Routing using partial
information for Wireless Ad Hoc
Networks”, R. Jain, A. Puri and R.
Sengupta
A routing protocol for wireless ad hoc
networks using information about
geographical location of nodes.
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Web over Wireless Group
Architecture
Multi-threaded
 Location Advertisement Protocol
 Geographic Routing Protocol
 Route Discovery Protocol
 Routing Table Update Daemon
Assumes the presence of a GPS system at
each node in the network
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Web over Wireless Group
Geographical Routing Protocol
When a node receives data packet :
Check_final_destination
if (final_destination is a neighbor)
forward the packet
else
check the routing table, find the
closest neighbor to this destination
and then forward the packet to that
neighbor
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Web over Wireless Group
Route Discovery Protocol
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If a node can not send a packet to a
destination because of a physical barrier it will
use a DFS type of algorithm in order to find an
alternate route to the destination.
When the route discovery packet reaches the
final destination, the destination node will send
the packet back to the sender and this way the
sender will discover the route to that specific
destination
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Web over Wireless Group
Packet Format
Eth. Header
Geog. Header WTP Hdr
Data (if any)
• Route advertisement and route discovery
packets don’t need the data field (i.e. length
field in the geographic header is equal to the
length of the geographic header)
• Length field for Data packets is equal to the
length of geographic header + length of data
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Web over Wireless Group
Geographic Header
Src Loc + MAC Dst Loc + MAC Checksum
 Location: UTM Location of the node
 MAC: MAC Addr of the node
 Checksum: checksum over the header
 Packet Len: length of the packet
 Seq: Sequence number
 Opts: options (TBD)
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Web over Wireless Group
p.len seq
opts
UTM Coordinates
The Universal Transverse Mercator projection and
grid system was adopted by the U.S. Army in 1947
for designating rectangular coordinates on large
scale military maps. UTM is currently used by the
United States and NATO armed forces.
Why UTM?
• Supported by all GPS receivers
• Simpler to use than latitude and longitude.
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Web over Wireless Group
Demo Scenario
Dst
Gw
C
C
B
B
C
11.0.1.21
{ 500000, 4000500, 100 }
• MAC Filter
• Transport Layer
WTP
11.0.1.20
B{ 500500, 4000250, 100 }
Dst
Gw
A
A
B
B
C
B
4/2/2002
11.0.1.19
A{ 500000, 4000000, 100 }
Web over Wireless Group
Dst
Gw
A
A
B
B
C
C
WOW Mobile IP
Web over Wireless Group
Overview
 IP Mobility Support, C. Perkins, RFC 2002
 Protocols
 Tunneling (HA – FA)
 Registration (MA - FA - HA)
 Agent Advertisement (FA)
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Web over Wireless Group
Mobile IP
10.0.2.0
subnet
Foreign Agent #1
10.0.2.2 & 11.0.1.2
Mobile Agent
11.0.1.10
Home Agent
10.0.1.2
Correspondent
Host 10.0.1.4
Router
10.0.1.0
subnet
10.0.1.1
10.0.2.1
10.0.3.1
10.0.3.0
subnet
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Web over Wireless Group
Foreign Agent #2
10.0.3.2 & 11.0.1.3
Mobile Agent
11.0.1.10
Registration
Mobile needs to make the home agent
aware of its present location i.e, the care
of address
Using UDP
 Registration request (mobile -> home)
 Registration reply (home -> mobile) contains
duration of validity (~100 seconds)
 What if UDP packet is dropped!!
Request sent again after reasonable time
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Web over Wireless Group
Tunneling
Encapsulation is done for redirection
Home agent tunnels the packet to the
care of address
Destination foreign agent de-tunnels the
packet and transmits it to the mobile
Packets from mobile to correspondent
host go directly (with source IP as
original (fixed) IP of the mobile node)
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Web over Wireless Group
MA Software
 Listens the Agent Advertisement
broadcasts sent by the FAs
 Registers with FAs automatically
depending on
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S/N over the link , signal qualities, BER
The bandwidth available on the link
The encryption provided on the network
The cost
Web over Wireless Group
Demo Setup
CH: Netmeeting (video + audio)
10.0.2.0
subnet
Mobile: OpenH323 Client
Foreign Agent #1
10.0.2.2 & 11.0.1.2
Mobile Agent
11.0.1.10
Home Agent
10.0.1.2
Correspondent
Host 10.0.1.4
Router
10.0.1.0
subnet
10.0.1.1
10.0.2.1
10.0.3.1
10.0.3.0
subnet
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Web over Wireless Group
Foreign Agent #2
10.0.3.2 & 11.0.1.3
Mobile Agent
11.0.1.10
FAST HANDOFF with position
based routing
Intra-Domain Handoff
•Takes packet from HA or CH.
Gatew
ay
•Decapsulates and checks its visitor list.
DFA
FA1
FA3
FA2
FA4
DFA
FA7
•Sends the packet to the related branches
according to Location FA table.
FA
FA5
FA6
•If it is an adjacent FA, buffer the packets.
•Else send the packet to the related
branches according to Location FA table.
FAST HANDOFF
FAST HANDOFFS with GPS for MOBILE IP
WW
BERKELEY
O
MEWLANA
Mobile Enriched Wireless Local Area Network Architecture
MEWLANA-Mobile IP Enriched
Wireless Local Area Network Architecture
WOW
SENSOR NETWORKS
Scheduling and Positioning
Problems for Sensor Networks