A Handoff Architecture with Relay Agent in
Nested Mobile Networks
1Jae
Kul Lee, 2Choong Seon Hong
1,2 School of Electronics and Information, Kyung Hee University
Korea 449-701
jaekul75@networking.kyunghee.ac.kr, cshong@khu.ac.kr
Introduction
 The evolution of information technology has enabled a
mobile object such as person, car, bus, train, airplane, or
ship to carry a plethora of information device
 Although Mobile IPv6 can be considered as a solution for
the problem, it does not support in the situation
 Routing is inefficient in nested mobile networks with
several subnets
 This paper proposes an architecture and element to
support packet routing for mobile networks
Packet Format of the Binding Update
0
A|H|R|D|P|Rervd
8
Prefix Length
16
23
Option Type
Option Length
Sequence Number
Lifetime
Sub-Options
Table 1. Binding update option format
0
8
16
Sub-Option Type
Sub-Option Len
Prefix Length
MONET Prefix
Table 2. MONET prefix sub-option
23
Operation of main components
 Correspondent node operation
 Checks validity of binding update
 Creates a new entry in binding cache
 Looks for entry corresponding to the destination address
 Home agent operation
 Checks validity of binding update
 Tunnels the packet to the CoA coincide with a prefix
 Mobile router operation
 Sends the prefix scope binding update to its HA
 Decapsulates packet and send packet to the original
destination
 Sends prefix scope binding update to the original sender
Scenario of mobile network
Routing Table :
Prefix2 -> MR2
Prefix3 -> MR2
:
:
Binding Cache :
MR2 -> CoAMR2
Prefix2 -> CoAMR2
Prefix3 -> CoAMR2
Routing Table :
Prefix1 -> MR1
:
: Binding Cache :
MR1 -> CoAMR1
Prefix1 -> CoAMR1
HAMR1
(1)
CN
FR
Stationary Network
HAMR2
(2)
FR
FR
(3 )
Mobile Network
(e.g., Train)
MR2
FR
FR
(4 )
Mobile Network
(e.g., Person)
MR1
(5 )
LFN1
Figure 1. Traditional nested mobile network
LFN2
Handoff within the nested mobile network
Routing Table :
Prefix2 -> MR2
Prefix3 -> MR2
Routing Table :
Prefix1 -> MR1
:
Binding Cache :
MR1 -> CoAMR1
Prefix1 -> CoAMR1
:
Binding Cache :
MR2 -> CoAMR2
Prefix2 -> CoAMR2
Prefix3 -> CoAMR2
HAMR1
CN
FR
Stationary Network
HAMR2
FR
FR
Mobile Network
(e.g., Train)
MR2
FR
FR
Prefix 3
Prefix 2
MR1
Prefix 1
LFN1
LFN2
Figure 2. Handoff within the nested mobile network
Proposed Architecture
 MRA(Mobile Relay Agent)
 Role
 Upon receiving a packet, the MRA set it’s address in this
packet and relays it to next MRA or destination
 Manage cache to support for mobile node or networks
 Assignment
 MRA is dynamically assigned mobile router on the path
when mobile node or router sends Binding Update
massage to Home Agent
Operation scenario in proposed
Architecture
Routing Table :
Prefix2 -> MR2
Prefix3 -> MR2
Routing Table :
Prefix1 -> MR1
:
Binding Cache :
MR1 -> CoAMTA2
Prefix1 -> CoAMTA2
:
Binding Cache :
MR2 -> CoAMTA2
Prefix2 -> CoAMTA2
Prefix3 -> CoAMTA2
HAMR1
(3)
CN
FR
Stationary Network
(4)
(2)
HAMR2
FR
FR
Mobile Network
(e.g., Train)
MTA2
FR
Binding Cache :
MR1 -> CoAMTA1
Prefix1 -> CoAMTA1
FR
(5 )
Prefix 2
Mobile Network
(e.g., Person)
MTA1
(6 )
Prefix 1
(1 )
LFN1
Figure 3. Scenario in nested mobile network with MRA
Prefix 3
LFN2
Handoff in proposed Architecture
Routing Table :
Prefix2 -> MR2
Prefix3 -> MR2
Routing Table :
Prefix1 -> MR1
:
:
Binding Cache :
MR2 -> CoAMRA2
Prefix2 -> CoAMRA2
Prefix3 -> CoAMRA2
Binding Cache :
MR1 -> CoAMRA2
Prefix1 -> CoAMRA2
HAMR1
Stationary Network
CN
FR
HAMR2
FR
FR
Mobile Network
(e.g., Train)
MRA2
FR
Binding Cache :
MR1 -> CoAMTA1
Prefix1 -> CoAMTA1
FR
Prefix 2
MRA1
LFN1
LFN2
Figure 4. Handoff within the nested mobile network
Prefix 3
Simulation(1)
Figure 5. Response time of HTTP
Figure 6. Average of response time in the FTP download
Simulation(2)
Figure 7. Response time of DB Query
Figure 8. End-to-end of Video conference
Conclusion
 This paper proposes MRA that supports route optimization
in the nested mobile network
 Mobile IPv6 with MRA allows top-level Router on a mobile
network to directly communicate with CN
 The simulation corresponding to response time of HTTP,
FTP, DB and end-to-end delay of video conference shows
that the proposed method is much better than the existing
one