An Overview of the Web over Wireless Group

1
An Overview of the Web over Wireless Group

• Web over Wireless Group
• UC, Berkeley

2
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

• http//wow.eecs.berkeley.edu

3
Research Focus

• Cellular networks
• Ad Hoc wireless networks
• Sensor networks
• Applications

4
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

5
Heterogeneous Wireless Networks

• 802.11 Wireless LANs
• Upto 50 Mbps
• Unlicensed spectrum
• Cheap and easy to set up
• Hot spot coverage with wireless LANs
• Mobility between networks
• Applications

6
Ad Hoc Wireless Networks

• Wireless token ring
• DSDV routing
• Geographical routing
• WTP
• Sensor Networks

7
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

8
DSDV - Wireless Routers
Internet
Wireless Router

• Cheaper/better performance cellular networks
• Ad Hoc wireless networks

9
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

10
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
• Doesnt use congestion control
• Small WTP headers
• Message based protocol

11
Network Architecture
TCP/UDP/WTP
Transport Layer
Mobility Management
Geographic routing, DSDV, QOS, TBRF, STARA
Network Layer
Data Link
Token ring, bluetooth 802.11, Seedex
MAC
Physical Layer
OFDM
12
Mobility and Internetworking Among Networks
Internet
802.11
Token Ring
DSDV
Geographic Routing
Sensor Networks
13
Technology

• Wireless Token Ring
• DSDV routing
• Geographical routing and WTP
• Mobile IP
• Fast Handoff
• MEWLANA
• Sensor Networks

14
WIRELESS TOKEN RING PROTOCOL
15
Introduction

• 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.

16
Descriptions (Operations)

• Joining Stations periodically invite other nodes
  to join the ring by broadcasting the available
  resources left in the medium

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.
17
Descriptions (Management)

• Ring Recovery Able to recover quickly by keeping
  information about topology of the ring, recovers
  from multiple simultaneous faults by taking
  increasingly drastic actions

Token Recovery Multiple token is deleted using
unique priority of token based on generation
sequence number and token ring address pair.
18
WTRP Deliverables
19
WTRP USER-SPACE
20
WTRS-WTR Simulator
21
Performance Analysis
22
Performance Analysis
23
DSDV Routing
24
DSDV Routing Protocol

• Based on Bellman-Ford algorithm
• Use sequence number to avoid loop-forming 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

25
System Architecture
26
Events of DSDV Protocol

• 1.Timers
• Periodical updates (30-second)
• Random offset timer (at most 30-second)
• Timeout (30-second)
• garbage-collection (120-second)
• 2.Input processing
• Request
• Response
• response to a specific query
• regular updates
• 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

27
Timers in DSDV

• Periodical updates (T)
• send the full routing table to the neighbors.
• Random offset timer (ltT)
• suppress the triggered updates and avoid
  unnecessary collisions on broadcast networks.
• Timeout (3T)
• 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 (3T)
• the route is deleted from the table and no longer
  included in all updates with a metric of infinity.

28
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

29
Geographical Routing
30
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.

31
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

32
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
33
Route Discovery Protocol

• 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

34
Packet Format
Eth. Header
Geog. Header
Data (if any)
WTP Hdr

• Route advertisement and route discovery packets
  dont 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

35
Geographic Header
Src Loc MAC
Dst Loc MAC
Checksum
p.len
seq
opts

• 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)

36
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.

37
Demo Scenario

• MAC Filter
• Transport Layer
• WTP

Dst Gw
C C
B B
Dst Gw
A A
B B
C C
Dst Gw
A A
B B
Dst Gw
A A
B B
C B
38
WOW Mobile IP
39
Overview

• IP Mobility Support, C. Perkins, RFC 2002
• Protocols
• Tunneling (HA FA)
• Registration (MA - FA - HA)
• Agent Advertisement (FA)

40
Mobile IP
10.0.2.0 subnet
Foreign Agent 1 10.0.2.2 11.0.1.2
Home Agent 10.0.1.2
Correspondent Host 10.0.1.4
Router 10.0.1.1 10.0.2.1 10.0.3.1
10.0.1.0 subnet
Foreign Agent 2 10.0.3.2 11.0.1.3
10.0.3.0 subnet
41
Registration

• Mobile needs to make the home agent aware of its
  present location i.e, the care of address
• Using UDP
• Registration request (mobile -gt home)
• Registration reply (home -gt mobile) contains
  duration of validity (100 seconds)
• What if UDP packet is dropped!!
• Request sent again after reasonable time

42
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)

43
MA Software

• Listens the Agent Advertisement broadcasts sent
  by the FAs
• Registers with FAs automatically depending on
• S/N over the link , signal qualities, BER
• The bandwidth available on the link
• The encryption provided on the network
• The cost

44
Demo Setup
CH Netmeeting (video audio) Mobile OpenH323
Client
10.0.2.0 subnet
Foreign Agent 1 10.0.2.2 11.0.1.2
Home Agent 10.0.1.2
Correspondent Host 10.0.1.4
Router 10.0.1.1 10.0.2.1 10.0.3.1
10.0.1.0 subnet
Foreign Agent 2 10.0.3.2 11.0.1.3
10.0.3.0 subnet
45
FAST HANDOFF with position based routing
Intra-Domain Handoff

• DFA
• Takes packet from HA or CH.
• Decapsulates and checks its visitor list.
• Sends the packet to the related branches
  according to Location FA table.
• FA
• If it is an adjacent FA, buffer the packets.
• Else send the packet to the related branches
  according to Location FA table.

46
FAST HANDOFF
47
MEWLANA Mobile Enriched Wireless Local Area
Network Architecture
48
SENSOR NETWORKS