Mobile IP

1
Mobile IP

• Chakchai So-In
• Department of Computer science Washington
  University

2
Outline

• Why Mobile IP?
• Mobile IPv4 basics
• Issues on Mobile IP
• Mobile IPv6 improvement
• Mobility Support in IP
• Conclusion

3
Why Mobile IP?

• Motivation for Mobile IP
• TCP session need to keep the same IP address for
  the life of the session
• IP needs to change the IP address when mobile
  node moves to a new place
• Consider the IP mobility problem as a routing
  problem
• Requirement for Mobile IP
• Transparency
• Compatibility
• Efficiency and scalability

4
Mobile IPv4 basics

• Mobile IP Terminology
• Mobile IP Functionality
• Mobile IP Operation

5
Mobile IP Terminology

• Mobile Node (MN)
• Foreign Agent (FA)
• Home Agent (HA)
• Care of Address (COA)
• Foreign agent-based COA/ Colocated COA
• Correspondent Node (CN)
• Security Parameters Index (SPI)
• Tunneling

6
Mobile IP Functionality

• Agent Discovery
• Agent Advertisement/ Solicitation
• Move Detection (Handover)
• Lifetime based and Network Prefix
• Registration (inform HA for COA)
• Routing and Tunneling
• Encapsulation
• IPinIP (RFC2003), Minimal encapsulation
  (RFC2004), GRE (RFC 2784)
• Triangle routing

7
Agent Advertisement
0
7
8
15
16
31
24
23
ICMP Router Discovery Protocol (IRDP RFC
1256) Type 16 Length 6 4 COAs R
Registration required B Busy, no more
registrations H Home agent F Foreign agent M
Minimal encapsulation G GRE r Sent as 0,
ignored on reception T FA supports reverse
tunneling reserved Sent as 0,
ignored on reception
Type
Checksum
Code
addresses
Addr. size
Lifetime
Router address 1
Preference level 1
Router address 2
Preference level 2
. . .
8
Registration

• UDP
• Registration Request
• Registration Reply

Source Port
Destination Port 434
Length
Check Sum
9
IP-in-IP-encapsulation
original IP header
original data
new data
new IP header
outer header
Inner header
original data
length
DS (TOS)
ver.
IHL
IP identification
flags
fragment offset
TTL
IP-in-IP
IP checksum
IP address of HA
Care-of address COA
length
DS (TOS)
ver.
IHL
IP identification
flags
fragment offset
TTL
Protocol
IP checksum
IP address of CN
IP address of MN
TCP/UDP/ ... payload
10
Minimal Encapsulation

• Avoid repetition of identical fields

11
Generic Routing Encapsulation
length
DS (TOS)
ver.
IHL
IP identification
flags
fragment offset
TTL
GRE
IP checksum
IP address of HA
Care-of address COA
protocol
rec.
rsv.
ver.
C
R
K
S
s
offset (optional)
checksum (optional)
key (optional)
sequence number (optional)
routing (optional)
length
DS (TOS)
ver.
IHL
IP identification
flags
fragment offset
TTL
Protocol
IP checksum
IP address of CN
IP address of MN
TCP/UDP/ ... payload
12
Mobile IP Operation
1. Sender (CN) sends to the MN address, HA
catches packets (proxy ARP) 2. HA make a tunnel
and forward packet to COA by
encapsulation 3. FA forwards the packet to the
MN 4. MN sends packet to CN as usual
13
Issues on Mobile IP

• Routing Optimization
• Mobile IP Handover/Handoff
• QOS
• Multicast
• Security (AAA)

14
Routing Optimization

• Optimization Strategies (Lifetime)
• Binding Cache (draft-ietf-mobileip-optim-11)
• Binding request and updates
• Binding warning
• Handoff/ Out of date cache
• Secure Binding Message IPSec (RFC 3776)
• Foreign Agent Smooth Handoff
• Previous FA reencapsulates a datagram with the
  right COA and sent it to MN (Relay)

15
Binding Cache/Warning/ Handoff
Binding Update
16
Mobile IP Handover/Handoff

• Hard Handoff/ Soft Handoff Yu et all, 2003
• Forward Handoff/ Backward Handoff

17
QOS

• QOS functionality M. Taha et all, 2005
• IntServ (Mobile RSVP)
• DiffServ Extension
• Mobile IP over MPLS

18
Multicast

• Home agent-based multicast
• Foreign agent-based multicast
• Multicast support for Mobile IP with the
  hierarchical local registration approach
• Range-based mobile multicast
• Richard LIN, 2002

19
Security

• Ingress Filtering (RFC2827)
• Reverse Tunneling (RFC3024)
• Replay attacks
• Timestamp Nonce
• Bogus Registration (DOS)
• Authentication (shared keys) Still difficult
  for key distribution/ management
• Firewall (draft-ietf-mobileip-firewall-trav-00,
  draft-ietf-mip6-firewalls-04 )
• Enable UDP 443 security channel (optional)

20
Reverse Tunneling
21
Authentication

• IP authentication Header (RFC2402)
• HMAC-MD5 (RFC2104)
• IP Encapsulating Security Payload (ESP)
• (RFC4303)

22
Mobile IPv6 improvement

• MIPv6 is a part of IPv6 not UDP message
• MIPv6 support End-to-End IPSec (RFC3776)
• No need for FA
• Automatic movement detection Neighbor Discovery
  (RFC2461)
• Obtaining IP address either DHCP or auto
  configuration Stateless address auto
  configuration (RFC2462)
• All routers perform router advertisement
  (co-located only)

23
Mobile IPv6 improvement (cont.)

• Route Optimization (Return Routability)
• MN can communicate directly to CN
• Destination Option (binding update integrated in
  IP packet)
• Fast hand-over (RFC4068)
• Home Agent Discovery (DHAAD)
• Dynamically choose HA from a subnet
• Hierarchical Mobile IPv6 (HMIPv6)
• Localizing the signaling when MN moves within a
  region (draft-ietf-mipshop-hmipv6-04)

24
Mobility Support in IP

• Mobile Classification Saha et all, 2004
• Micro mobility movement within a subnet
• Macro mobility within a domain different subnets
• Global mobility across different domains
• Network overhead, much delay, and packet lost
• Protocol Performance

25
Mobility Support in IP (cont.)
Mobility
Global
Micro
Macro
MIP (1996)
HMIP (1996)
TR45.6 (1996)
CIP (1998)
Hawaii (1996)
TeleMIP (2000)
DMA (2000)
MIPv6 (2001)
TMIP (2001)
HMIPv6 (2001)
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(No Transcript)
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Conclusion

• Mobile IPv4v6
• Mobility Issues
• All-IP-based wireless