Transcript Dynamic Tunneling Configuration for Network with Uni

Dynamic Tunneling Configuration for
Network with Uni-Directional Link
ICCC99 – 15/09/1999
Mikiyo NISHIDA / KEIO Univ.
Hiroyuki KUSUMOTO / KEIO Univ.
Jun MURAI / KEIO Univ.
General Description
• Introdunction
– Characteristics of Uni-Directional Link
• Current Problems of Uni-Directional Link
• Scheme
– Dynamic Tunneling Configuration
• Design
– Message based mechanism
• Implementation
– Implement our mechanism
• Conclusion
Introduction(1) UDL
• Uni Directional Link
– One-way (most case:Multiple Access)data link
• Satellite
• Cable TV
Introduction(2)
Network with UDL
• Network with UDL
& BDL (BiDirectional Link)
– We assume UDL
network in the
Internet has UDL
and another BDL
accessibility
Introduction(3)
Tunneling Techniques
• For Simulating link solution
– tunneling
• Current Tunneling Scheme
– Static Configuration
– Few Scalability
– Too much management cost
We propose
‘ Dynamic Tunnel Configuration Scheme’
Current Problems(1)
Routing in network with UDL
• Current Internet Routing Protocol
– Based on Link Bi-directonality
• Approaches for using UDL network
– Modify Routing Protocol
– Provide Bi-Directional accessibility for UDL
virtually
Current Problems(2)
Data-link address resolution in UDL
• Multiple access data-link requires data-link
address resolution
– Ethernet use ARP protocol
Current Problems(3)
IP Address Assignment in UDL
• UDL has a lot of receivers
• IP address is limited resource
Current Problems - Overall
• Routing Problems
• Data-link address resolution
• IP Address Assignment
Dynamic Tunneling Scheme(1)
• We propose Dynamic Tunneling
Configuration Scheme
– Provide virtual return path of UDL
automatically
– Provide mechanism of data-link address
resolution on UDL
– Provide mechanism of IP address dynamic
assignment
Dynamic Tunneling Scheme(2)
• Message based mechanism
–
–
–
–
–
Exchange messages over UDL and BDL
UDL Keepalive
Setup/Shutdown tunnel
Data-link address resolution
IP Address Automatically Assignment
Design(1) General Description
Design(2) Messages
• Notify Message (via UDL)
– Sender to Receiver
• HELLO message
– Notify Sender Information
– Applied UDL Keep Alive
Design(3) Messages
• Control Message (via BDL)
– Exchange each other
• REQUEST Message (Receiver to Sender)
– Notify Receiver beginning to use UDL
– Request Tunnel Setup, IP Address Assign
• REPLY Message (Sender to Receiver)
– Reply for Receiver’s message
• REFRESH/RELEASE Message (Receiver to Sender)
– Notify Receiver uses UDL continuously / terminate using
UDL
Design(4) Modules
• Virtual Link Module
– Manipulate tunneling packets
• Control Module
–
–
–
–
Manipulate messages
Set/Release tunnel
Set/Release interface’s IP address
Maintain IP/DL address
Design(5) Operating cycle
Implementation(1)
• Target Architecture:
– FreeBSD 2.2.1-Release
• Modified data-link routine in Unix Kernel
• UDL: Use Ethernet (Modified Output Routine)
• BDL: Use Ethernet
• Virtual Link Module is implemented in Unix
Kernel
• Control Module is implemented as user process
application
Implementation(2)
Virtual Link Module
• Total of 120 lines:
– if_ethersubr.c
• ether_input(), ether_output()
• Add encapsulation/decapsulation function
– if.c
• if_ioctl()
• Add manipulating tunnel information function
Implementation(3)
Control module
• Code size
– Total of 1450 lines / at Receiver
– Total of 1436 lines / at Sender
• Implement as user process application
• Send and receive messages via UDP
• Maintenance DL/IP address table
Conclusion
• Describe current problems of network with
unidirectional link
• Propose Dynamic Tunnel Configuration
Scheme
• Implement our proposed mechanism
• Present usability of this scheme
Future Work
• Test many types of routing protocols
• Improve performance and scalability