Transcript Solution Approach

An End-to-End Approach
to Host Mobility
MobiCom ’00
Alex C. Snoeren and Hari Balakrishnan
MIT Lab. For Computer Science
Presenter: SangJeong Lee (3/18)
Problem
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Supporting Host Mobility
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Mobile? (mid ‘90s ~)
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Addressing
Locating a mobile host
Seamless connection
Existing Solution
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Network level approach
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Application level approach
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Mobile IP: pure routing solution, transparent to upper layers, triangle
routing, weak to ingress filtering, permanent home address
Proxy approach, client part
Transport level approach
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MSOCKS: redirection using split-connection proxy at transport layer
The paper’s work
Solution Approach
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Solution Approach
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Addressing
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Locating a mobile host
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Manual, DHCP, or auto-configuration protocol
Don’t care
No third-party agents
DNS lookup
Secure DNS update
Seamless connection
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End-to-end approach
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No third-party agents
TCP connection migration
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Add TCP migration option
Solution Approach (Cont.)
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Security Issues
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Denial of service
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Connection hijacking
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Replayed Migrate SYNs  Ignore duplicate Migrate SYNs
Bogus Migrate SYNs  New Migrate-Permitted option after
handovers
Key security
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Migrate request (SYN): validation check with pre-computable token
(1/264)
ECDH
IPSec
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Security associations (SAs) and security policy database (SPD) are
on IP-address basis
Beyond the scope of the paper
Strong Points
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End-to-End Approach
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No third-party participants
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Routing optimization
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Performance
Avoid ingress filtering due to DOS attack
Not consider IP address as an identity of a host, just an attachment
point
Transport Approach
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More deployable than Mobile IP
Deployed as TCP option  Backward compatible
Application is aware of handovers  optimization
Weak Points
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Deployment Issues
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Changes to transport protocol
Address caching generally
Proxies and NATS  Secure?
Simultaneous Moves
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Primarily targeting infrastructure-based
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Not ad-hoc network topology
No Performance Comparison
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Not experiment, but prototyping
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Just proving that it behaves well
New Ideas
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Simultaneous Moves
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Fast Handover
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Issuing three DUP-ACKs immediately after migration
Different bandwidths of before- and after-migration
Deployment
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Effective way
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Mobile IP, Multicast, Active Network, …
Backward compatibility
Mobile IP Overview
Sender
Home Agent
Foreign Agent
Tunnel
Home Address
Handoff
Mobile Host
Care-of Address
TCP Connection Migration
TCP Migrate-Permitted Option
TCP Migrate Option
MIGRATE_WAIT State