Download 4x4 Optimization

4x4 Optimization
Alkesh Patel
&
Hemant Patel
Background
IP address – identify computer on the network
Mobile domain - mobile host

IP address is not restricted to region
Problem : Identifying computer on mobile domain
Solution:


Change IP address when the host moves to other subnet
Use same IP address and add special routing entries to
track the current location of the user – good for small
group
Challenge
Following challenges should be solved before
considering solution



Compatibility: Should work with current wired internet
infrastructure
Scalability: Should be able to support large number of
user to meet future demands
Transparency: User should not feel difference
between wireless and wired network
Optimization
Optimization scheme should ensure

Guaranteed delivery

Low latency

Low overhead
4x4 Approach
Four options for packets direction






IN approaches CN to MN
OUT approaches MN to CN
s – outer source in the encapsulated packet
d – outer destination in the encapsulated packet
S – inner source of the packet
D – inner destination of the packet
The IN strategies in 4x4 approach
IN Strategy
s
d
S
D
Acceptable
Combinations
Notes
Incoming Indirect
Encapsulated
(IN-IE)
IP address
of HA
COA of
the MN
IP address
of the CN
Home IP address
of the MN
1. Highest overhead
2. Guaranteed delivery
Uses tunneling
CN need not be mobility aware
OUT-IE
OUT-DE
OUT-DH
Incoming Direct
Encapsulated
(IN-DE)
IP address
of CN
COA of
the MN
IP address
of the CN
Home IP address
of the MN
1. CN is mobility aware
2. No tunneling
OUT-DE
OUT-DH
Not
applicable
Not
applicable
Home IP address
of the MN
1. No encapsulation
2. Usable when there
are no security constraints
at intervening routers
3. MN and CN on same subnet
OUT-DH only
Not
applicable
Not
applicable
COA of MN
1. MN cannot receive
packets addressd to
its orginal IP address
2. Useful for short-term
communication
OUT-DT only
Incoming Uses Home
Address
(IN-DH)
Incoming Direct
Uses Temporary
address
(IN-DT)
IP address
of the CN
IP address
of the CN
The OUT strategies in 4x4 approach
OUT Strategy
s
d
S
D
Notes
Acceptable
Combinations
Outgoing Indirect
Encapsulated
(OUT-IE)
COA of
the MN
IP address
of HA
Home IP address
of the MN
IP address
of the CN
1. Highest overhead
2. Guaranteed delivery
3. No ingress filtering
4. CN need not
be mobility aware
IN-IE only
Outging Direct
Encapsulated
(OUT-DE)
COA of
the MN
IP address
of CN
Home IP address
of the MN
IP address
of the CN
1. CB is mobility aware
2. No tunneling
IN-IE
IN-DE
Outgoing Direct
Home Address
(OUT-DH)
Not
Applicable
Not
Applicable
Home IP address
of the MN
IP address
of the CN
1. No encapsulation
2. Usable when there
are no security
constrains at the intervening routers
3. MN and CN on the same subject
IN-IE
IN-DE
IN-DH
Outgoing Direct
uses Termporary
Address
(OUT-DT)
Not
Applicable
Not
Applicable
COA of MN
IP address
of the CN
1. MN cannot receiver
packets addressed to its
original IP address
2. Useful for shortterm communication
IN-DT only
Comparison & Evaluation
16 different strategies for transmission


Four approaches for each of the two directions
Different advantages & disadvantages
Choice based on session basis or packet-to-packet
basis