The k-hop Architecture

1
The k-hop Architecture

• A Scalable Approach to Routing in Ad Hoc Wireless
  Networks

William List, Jungmin So and Nitin Vaidya
2
Motivation

• Ad Hoc Routing Protocols scale poorly
• Long routes hurt performance
• Routing tables are too large
• Wireless LANs are popular and cheap
• Can be extended to multiple hops
• Improves spatial reuse and connectivity
• Provides a fixed backbone
• Wireless LAN MANET hybrid network

3
What is the k-hop Architecture?

• Limited Ad Hoc Range
• Connections between ad hoc hosts are restricted
  to k wireless hops
• Backbone Infrastructure
• Network of base stations keep the ad hoc hosts
  connected
• A route that uses base stations can contain up to
  2k wireless hops

4
Sample k-hop Network (k 2)

• Mobile Node (MN)
• Base Station (BS)
• Connection
• MN K has limited connectivity
• MN F can use BS X and BS Y
• Connection C to G can use path C ?D ? G (two
  hops) or C ? Z ? X ? J ? G (three
  hops)

A
A
B
G
X
X
J
K
D
E
H
F
C
I
Y
Z
5
Routing

• Local routing
• Proactive (i.e., DSDV)
• Limited to k wireless hops away
• Defines the coverage area for each BS
• Remote routing
• Between BSs
• On-demand (i.e., AODV)

6
Local versus Remote Routing

• Mobile Node (MN)
• Base Station (BS)
• Connection
• Routing for MN C
• Local MNs
• Remote MNs (reachable only through BS Z)
• K is unreachable

A
A
B
G
X
X
J
K
D
E
H
F
C
I
Y
Z
7
Services

• Existing
• Address assignment via modified DHCP
• Internet accessibility
• Proposed
• Load balancing
• W911, Where am I?
• e-cash

8
Applications

• Campus and business infrastructure
• Military and emergency relief
• Research (UIUC testbed)
• Channel selection and switching
• Network monitoring and visualization
• The effect of the k bound on the network
• Security

9
Status

• Linux Implementation
• Written in C
• MN daemon and BS daemon
• Runs in user-space
• Uses Ad Hoc Support Library (ASL)
• Only packets with unknown destinations are copied
  to user-space from the kernel
• Includes LL feedback support