Routing in Mobile Networks
Professor Ching-Chi Hsu
Part I. Mobile IP on Network Layer
Part II. Routing in Mobile/Wireless Ad-hoc Networks
0
Mobile IP on Network Layer







DNS based Name to Address resolution
Network Layer Mobility Problem
Illustration of Terms in Mobile IP
Two Tier Addressing
Mobile IP Architecture Components
Address Translation Mechanisms
Mobile IP Proposals
1
DNS based Name to Address
resolution
2
Network Layer Mobility Problem
Directory Service View

DNS didn’t handle dynamic updates.

DNS design attempts to optimize the access cost, and not
the update cost.

There is no call back mechanism generally available from
servers to clients in case the cached entries of the DNS
clients become invalid.
3
Network Layer Mobility Problem
Internet View
TCP connection:
<source IP address, source TCP port, destination IP address, destination TCP port>

If the mobile host acquires a new IP address, all TCP
connections involving the mobile host will be broken.

If the mobile host retains its address, then the routing
system cannot forward packets to its new locations.
4
Illustration of Terms in Mobile IP
5
Two Tier Addressing
6
Mobile IP Architecture
Components
7
Address Translation Mechanisms
Encapsulation
8
Address Translation Mechanisms
Loose Source Routing
9
Mobile IP Proposals
Columbia Scheme
10
Mobile IP Proposals
Sony Scheme
11
Mobile IP Proposals
LSR Scheme
12
Mobile IP Proposals
IETF Scheme
13
Routing in Mobile/Wireless
Ad-Hoc Networks






Introduction
Definitions of Dynamic Groups Routing
Dynamic Groups Routing Algorithms
Simulation and Analysis
Conclusion
Future Works
14
Introduction

Ad-Hoc Networks Model

Previous Works on Routing in Ad-Hoc Networks

Motivations of Dynamic Groups Routing
15
Ad-Hoc Networks Model

Ad-hoc networks
 Wireless communication
 Without fixed network interaction and centralized administration.
 Multi-hop routing style with no cheating of the forwarding nodes
mobile host
routing
16
Ad-Hoc Networks Model

Why ad-hoc networks ?
 When the access base station are not set up due to low cost effect,
poor performance or low usage
 Ad-hoc networks may be the extension of base stations
Base station

Bridges
Ad-hoc networks
Applications of ad-hoc networks
 An outdoor conference
 Emergency situations of natural disasters
 Military deploys in battlefield
17
Previous Works on Routing in
Ad-Hoc Networks

On-demand dynamic source routing (D.B.Johnson et al.)

Cluster-based routing (P. Krishna et al.)

Zone routing (Z.J. Haas et al.)

Minimum connected dominating set routing (B. Das et al.)
18
On-demand dynamic source
routing



Loosely source routing while route requested
Each node may overhear the routing information from the
neighbor nodes.
Example: source routing and overhearing
source
destination
Route request message
Route reply message
Mobile node
Overhearing range
19
Cluster-based routing



The clustering method depends on the k-hop mutually
reachable relation between any two nodes in a cluster.
A two-level network graph - cluster-level + node-level
Example: 1-cluster(fully connected sub-graphs as clusters)
Mobile node
Cluster
20
Zone routing




Zone - the nodes within the defined radius
Radius - hop-count reachable from the central node
Each node maintain the topology in its zone
Example: zone with radius = 2
Mobile node
Zone
21
Minimum connected dominating
set routing



Minimum connected dominating set (MCDS) - construct a
so-called virtual backbone in an ad-hoc network.
Routing through the virtual backbone by dominators.
Example: virtual backbone construction
MCDS edge
Non-MCDS edge
Mobile node
dominators
MCDS(virtual backbone)
22
Comparison
Routing methods
Infrastructure
Advantages
Disadvantages
On-demand
Routing
Only sense the
neighbors
Less overhead to Frequent routing
maintain topology make it mass route
discovery overhead
Zone Routing
(cluster-based)
Uniform cluster
with the node
as the center
Easy to maintain
the topology in
zones
MCDS Routing
MCDS virtual
backbone as
routing trunk
Simple to search
routes by virtual
backbone
23
Frequent moving
causing heavy
topology update
Network grown
up make the virtual
backbone a heavy
burden
Motivations of Dynamic Groups
Routing

Ad-hoc network topology maintenance
 Range Consideration
 The whole network - inefficient and infeasible.
 Only neighbors - inefficient while frequent route requesting
 Structure Consideration
 Relative conectivity
 Relative position

To propose an easy topology maintenance and good traffic
isolation ad-hoc network routing system- Dynamic Groups
Routing
24
Definitions of Dynamic Groups
Routing

Illustration of an ad-hoc network construction

Definitions
 Dominating value definition
 Routing groups definitions
 Definitions of attachable sets, bridge and peripheral clusters
25
Illustration of an ad-hoc network
construction
A
B
C
D
H
N
E
I
K
J
L
F
G
P
M
O
Q
R
Positive cluster
Non-positive cluster
Routing group
26
Dominating value definition

Definition 1: DV(p) is the dominating value of a node p in
an ad-hoc network. It is calculated as the following before
the construction proceeds.
Initial DV(p) := 0
For each q which q in neighborhood of p
If deg(p) > deg(q)
then
DV(p) := DV(p) +1
else if deg(p) < deg(q)
DV(p) := DV(p) – 1

Theorem 1: In the initial constructed bi-directional
connected network, the summation of all dominating values
of nodes is zero.
27
Routing groups definitions

Definition 2: A node p is positive while DV(p) > 0,
otherwise non-positive.

Definition 3: In a constructed ad-hoc network, the cluster
formed by all connected positive nodes is called positive
cluster (P-cluster). The cluster formed by all connected nonpositive nodes is called non-positive cluster (N-cluster).

Definition 4: A routing group (RG) is formed by one Pcluster with its adjacent N-clusters
28
Definitions of attachable sets,
bridge and peripheral clusters

Definition 4: An attachable set is a set of all the positive
nodes in the same P-cluster with direct bi-directional links
to the same adjacent N-cluster

Definition 5: A bridge cluster is the N-cluster belonged to
more than one RG. On the other hand, the N-cluster
belonged to one RG is called peripheral cluster.
29
Dynamic Groups Routing
Algorithms

Construction algorithm

Route discovery strategy

Route maintenance

Connection recovery
30
Message propagating illustration
in construction
<2,-2>
Nlist(A),DV(A)
<3,0>
<3,-2>
B
M
A
<3,0>
D
H
<5,+2>
<2,-2>
Q
<2,0>
R
<2,-2>
<4,4>
<5,+2>
C
P
N
O
<3,-2>
<5,+2>
<5,+2>
E
I
K
<2,-1>
F
<2,-1>
G
J
<2,-1>
<2,-1>
31
L
<2,0>
Note: <degree, DV>
Construction algorithm
{For each mobile node p in the ad-hoc network}
Broadcast message deg(p) to all neighbors
Receive message deg(q) from each neighbor q
Calculate DV(p) as definition 1
Broadcast message {List(N(p)) ,DV(p)} to each neighbor q
Receive message {List(N(r)) ,DV(r)} from each neighbor q
For each message {List(N(r)) ,DV(r)}
Case 1. DV(p) > 0 & DV(q) > 0
Propagate it to all positive neighbors excluding q
Case 2. DV(p) > 0 & DV(q) <= 0
Propagate it to all positive neighbors
Case 3. DV(p) <= 0 & DV(q) <= 0
Propagate to all neighbors excluding q
Case 4. DV(p) <= 0 & DV(q) > 0
Ignore the message
32
Route discovery illustration

Intra-cluster
Intra-group
Inter-group
Intra-group
Inter-group
Intra-cluster
Mobile node
S
RG
P-cluster
N-cluster
33
Route discovery strategy
For a route request from the source node s to the destination node d
if (the node s is non-positive)
then it checks the local topology information of its N-cluster
if (the destination node d is found)
then it routes from the node s to the node d directly
else
it multicasts intra-group route request message to all the nodes in its attachable
sets and waits for reply message
if (all the reply message are failure)
then it issues inter-group route request message to all the nodes in its attachable sets
else it routes by the reply information from one of the nodes in its attachable sets
else it checks the local topology information of its routing group
if (the destination node d is found)
then it routes from the node s to the node d directly
else it multicasts inter-group route request message to all the nodes in the attachable
sets of all its bridge clusters,which also belong to other routing groups
34
Route maintenance(link variations)

6 kinds of reactions to the variations
Reacting/Interacting
node
Interacting/Reacting
node
Link
Hm
Hn
Connected/Disconnected
N/P
2
N/P
*
2
*
35
2
=8
Route maintenance(link variations)
Hm
P
Hn
P
P
N
N
N
P
P
N
P
P
N
N
N
P
N
Link(Hm,Hn) Action
Description
Disconnect
I
Hm propagates "Delete link(Hm,Hn)" to the hosts in the
same P-cluster. If the P-cluster isn’t connected, the RG is
splited.
Disconnect
II Hm propagates "Delete link(Hm,Hn)" to the hosts in the
same P-cluster. Hm is detached the N-cluster of Hn from
Hn .
Disconnect
III Hm propagates "Delete link (Hm,Hn)" to the hosts in the
same N-cluster or in its ASET
Connect
IV If Hn and Hm are the same P-cluster, Hm propagates
"Insert link(Hm,Hn)" to the hosts in the same P-cluster.
Otherwise Hm propagates "Insert RG topology of Hm" to
Hn and waits for the RG topology of Hn. Therefore, the
action joins two RGs.
Connect
V Hm propagates "Insert link(Hm,Hn)" to the hosts in the
same P-cluster. If Hn and Hm are not the same RG, Hm
waits for the N-cluser+ASET topology of Hn.
Connect
VI Hm propagates "Insert link (Hm,Hn)" to the hosts in the
same N-cluser or in its ASET. If Hn and Hm are not the
same RG, Hm propagates "Insert N-cluser+ASET
topology of Hm" to Hn.
36
Route maintenance
(connectivity dominating variations)
-1
DV(E): +2
G
A
B
D
E
F
H
I
C
37
Route maintenance
(connectivity dominating variations)
The connectivity dominating variation of Hm caused by the link variation of Hn
Initial DV(Hm) Deg(Hm)? deg(Hn)
>
P
=
P
<
P
>
N
=
N
<
N
>
P
=
P
<
P
>
N
=
N
<
N
LinkHmHn variation
Connected→disconnected
Connected→disconnected
Connected→disconnected
Connected→disconnected
Connected→disconnected
Connected→disconnected
Disconnected→connected
Disconnected→connected
Disconnected→connected
Disconnected→connected
Disconnected→connected
Disconnected→connected
Note: P: positive ; N: non-positive; →: link state transition from left to right
38
Updated DV(Hm)
P or N
P
P
N
N
N or P
P
P
P or N
N or P
N
N
Route maintenance
(connectivity dominating variations)
The connectivity dominating variation of Hm caused by the conectivity dominating variation of Hn
Initial V(Hm) Deg(Hm)?deg(Hn)
P
>
P
=
P
<
N
>
N
=
N
<
P
>
P
=
P
<
N
>
N
=
N
<
DV(Hn) variation
Decrement
Decrement
Decrement
Decrement
Decrement
Decrement
Increment
Increment
Increment
Increment
Increment
Increment
Note: P: positive ; N: non-positive
39
Updated DV(Hm)
P
P
P or N
N
N or P
N or P
P or N
P or N
P
N or P
N
N
Connection Recovery

Group-level backtracking to the last one
New route
N-cluster
N-cluster
N-cluster
P-cluster
RG1
P-cluster
RG2
40
Connection Recovery
Assume original discovered route from s to d. (s(a0)a1… an  d(an+1))
The corresponding attachable sets are A1,A2,….,An
For node ai
Search the topology information in the routing group of ai
If the destination node d is found
Routing is successful
Otherwise
Checking the connection status of ai+1
Case “Normal”
Routing performs on the next node ai+1.
Case “Broken”
(Recovery process performs on node ai)
Finding the other attachable sets from the routing group of ai.
If there are other attachable sets excluding the routing group of ai-1 and ai+1
Rerouting starts from these attachable sets.
Otherwise
Routing backtracks to ai-1 to find the other attachable sets excluding the routing group of
ai. Rediscovery process performs on ai-1.
Case “Merged”
Forwarding the routing process to ai+1.
Case “Attached”
Forwarding the routing process to the attachable set excluding the routing group of ai.
41
Simulations and Analysis

Simulation model

Simulation results
42
Simulation model

N mobile nodes move randomly in a square area
43
Simulation results

Connectionless
 Variant number of mobile hosts
 Variant moving frequency of mobile hosts
 Variant route query frequency of mobile hosts

Connection-oriented
 32 mobile hosts in 800m*800m area
 72 mobile hosts in 1200m*1200m area
44
Total delay in route maintenance phase by
increasing number of mobile hosts
Message Trip for Maintenance
70000
60000
DG Routing(mtc)
Zone Routing(mtc)
MCDS Routing(mtc)
Total hop count
50000
40000
30000
20000
10000
0
10
20
30
40
50
60
Number of mobiles
45
70
80
90
100
Control traffic in route maintenance phase
by increasing number of mobile hosts
Message Propagation of Maintenance
3000000
Number of message packets
2500000
DG Routing(mmc)
Zone Routing(mmc)
MCDS Routing(mmc)
2000000
1500000
1000000
500000
0
10
20
30
40
50
60
Number of mobiles
46
70
80
90
100
Control traffic in route discovery phase by
increasing number of mobile hosts
Message Propagation of Route Discovery
20000000
Number of propagated message packets
18000000
DG Routing(rmc)
Zone Routing(rmc)
MCDS Routing(rmc)
Flood Routing(rmc)
16000000
14000000
12000000
10000000
8000000
6000000
4000000
2000000
0
10
20
30
40
50
60
Number of mobiles
47
70
80
90
100
Total control traffic by increasing number
of mobile hosts
Message Propagation of Route Maintenance & Discovery
20000000
Number of propagated message packets
18000000
DG Routing(tmc)
Zone Routing(tmc)
MCDS Routing(tmc)
Flood Routing(tmc)
16000000
14000000
12000000
10000000
8000000
6000000
4000000
2000000
0
10
20
30
40
50
60
Number of mobiles
48
70
80
90
100
Total delay in route maintenance phase by
increasing moving frequency
Message Trip for Maintenance
35000
30000
Total hop count
25000
20000
15000
10000
DG Routing(mtc)
Zone Routing(mtc)
MCDS Routing(mtc)
5000
0
10
20
30
40
50
60
70
Frequency of movement(%)
49
80
90
100
Control traffic in route maintenance phase
by increasing moving frequency
Message Propagation of Maintenance
600000
DG Routing(mmc)
Zone Routing(mmc)
MCDS Routing(mmc)
Number of message packets
500000
400000
300000
200000
100000
0
10
20
30
40
50
60
70
Frequency of movement(%)
50
80
90
100
Control traffic in route discovery phase by
increasing moving frequency
Message Propagation of Route Discovery
Number of propagated message packets
3000000
2500000
2000000
DG Routing(rmc)
Zone Routing(rmc)
MCDS Routing(rmc)
Flood Routing(rmc)
1500000
1000000
500000
0
10
20
30
40
50
60
70
Frequency of movement(%)
51
80
90
100
Total control traffic by increasing moving
frequency
Message Propagation of Route Maintenance & Discovery
Number of propagated message packets
3000000
2500000
DG Routing(tmc)
Zone Routing(tmc)
MCDS Routing(tmc)
Flood Routing(tmc)
2000000
1500000
1000000
500000
0
10
20
30
40
50
60
70
Frequency of movement(%)
52
80
90
100
Total delay in route maintenance phase by
increasing routing frequency
Message Trip for Maintenance
35000
30000
Total hop count
25000
20000
15000
10000
DG Routing(mtc)
Zone Routing(mtc)
MCDS Routing(mtc)
5000
0
10
20
30
40
50
60
70
Frequency of route request(%)
53
80
90
100
Control traffic in route maintenance phase by
increasing routing frequency
Message Propagation of Maintenance
400000
350000
Number of message packets
300000
250000
DG Routing(mmc)
Zone Routing(mmc)
MCDS Routing(mmc)
200000
150000
100000
50000
0
10
20
30
40
50
60
70
Frequency of route request(%)
54
80
90
100
Control traffic in route discovery phase by
increasing routing frequency
Message Propagation of Route Discovery
Number of propagated message packets
60000000
DG Routing(rmc)
Zone Routing(rmc)
MCDS Routing(rmc)
Flood Routing(rmc)
50000000
40000000
30000000
20000000
10000000
0
10
20
30
40
50
60
70
Frequency of route request(%)
55
80
90
100
Total control traffic by increasing routing
frequency
Message Propagation of Route Maintenance & Discovery
60000000
DG Routing(tmc)
Zone Routing(tmc)
MCDS Routing(tmc)
Flood Routing(tmc)
Number of propagated message packets
50000000
40000000
30000000
20000000
10000000
0
10
20
30
40
50
60
70
Frequency of route request(%)
56
80
90
100
The message complexity comparison by connection time
duration with area = 800m*800m, number of mobile
nodes = 32, moving frequency =50%
Message Complexity
40000
DG without recovery
DG with recovery
Flooding routing
Zone routing
MCDS routing
number of propagated message packets
35000
30000
25000
20000
15000
10000
5000
0
10
20
30
40
50
60
70
connection time duration(#clicks)
57
80
90
100
The message complexity comparison by mobile node
moving frequency with area = 800m*800m, number of
mobile nodes = 32, connection duration = 50
Message Complexity
20000
number of propagated message packets
18000
16000
14000
12000
DG without recovery
DG with recovery
Flooding routing
Zone routing
MCDS routing
10000
8000
6000
4000
2000
0
10
20
30
40
50
60
moving frequency %
58
70
80
90
100
The message complexity comparison by connection time
duration with area = 1200m*1200m, number of mobile
nodes = 72, moving frequency =50%
Message Complexity
number of propagated message packets
140000
DG without recovery
DG with recovery
Flooding routing
Zone routing
MCDS routing
120000
100000
80000
60000
40000
20000
0
10
20
30
40
50
60
70
connection time duration(#clicks)
59
80
90
100
The message complexity comparison by mobile node
moving frequency with area = 1200m*1200m, number of
mobile nodes = 72, connection duration = 50
Message Complexity
160000
DG without recovery
DG with recovery
Flooding routing
Zone routing
MCDS routing
number of propagated message packets
140000
120000
100000
80000
60000
40000
20000
0
10
20
30
40
50
60
70
moving frequency %
60
80
90
100
Conclusion

A two-type cluster scheme is proposed to form the routing
groups structure, easily maintaining the routing environment
in ad–hoc networks.

It seems that this approach is adaptive to such domain for
reducing the control message propagation in ad-hoc
networks

Upon the basic constructed model of ad-hoc networks, the
route recovery method is developed for connection-oriented
applications
61
Future Works

Now a day many multicasting applications are applied in
mobile/wireless ad-hoc networks.

The next research subject is developing efficient multicast
routing methods in ad-hoc networks based on the
constructed dynamic groups model.
62