Mobility Support in Edge Routers Michael Eyrich Telecommunication - - PowerPoint PPT Presentation

Mobility Support in Edge Routers

Michael Eyrich Telecommunication Networks Group (TKN)

• Prof. Dr. Adam Wolisz

Technical University Berlin eyrich@ee.tu-berlin.de January 10, 2001

Outline

WUGS

• Quo vadis, DFN project?
• Aims of the DFN testbed
• Service platforms
• Remote Socket Architecture (ReSoA)
• Local testbed
• Last Hop Protocol: LLP
• Support Tool for test environment

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Quo vadis, DFN project?

WUGS

General project description

• potentialities and limits of a simple approach for Active networking
• application-specific services, specifically mobility

– terminal mobility – personal mobility → flexible service platform e.g., transport protocols for group communication Areas of application

• group- and mobile communication

– proving – evaluation

• analysis

– quality of service – safety – reliability

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Aims of the DFN testbed

WUGS

Aims

• prototypic realizations
• experiences in terms of

– appropriation – use of a flexible open service platform Steps

• 1. GNU/Linux based PCs with flexible
• pen service platform
• 2. Extension to high bandwidth IP over

WDM (on top or parallel to DFN network).

• 3. Opening to a broader range of users

testbed

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Service platforms

WUGS

Service platforms

• AMnet (Active Multicasting Network)
• ANN (Active Network Nodes)

based on WUGS (Washington University Gigabit Switch)

• Router Plug-ins

Desired results

• conclusions on necessary functionality
• cycling through steps of

→ conception → realization → evaluation

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Remote Socket Architecture (ReSoA)

WUGS

SPC? TCP IP LAN WLAN LHP WLAN LHP application Local Socket Module

user interface wireless end−system

socket interface TCP IP LAN application

user interface distant end−system

Export Socket Server

base station Export Protocol commandsand results exchange Internet

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ReSoA (cont.)

WUGS

ReSoA

• Remote Socket Architecture, consisting of:
• Export Protocol:

– transport layer proxy approach – Transfer of socket functionality

• Last Hop Protocol (LHP): e.g., Link Layer Protocol

– reliable transmission for TCP streams – semi-reliable transmission for UDP streams – implemented for GNU/Linux – implemented as virtual devices allowing for dynamically interchanging protocols.

• between edge router and mobile node

Open issues

• porting to ⋆ BSD-ish environment?
• porting Export Protocol to current Linux kernel version

(from 2.0.x to 2.2.x or 2.4.x)

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Last Hop Protocol: LLP

WUGS

Implementation of LLP

• Support layer for MAC protocols
• Reduction of unnecessary multi-hop retransmissions
• Device independent

(tested with ethernet and several wireless devices)

• packet path controlled by standard routing rules
• additional internal refinement (e.g., by ports) to improve transmission

reliability for selected applications (e.g., NFS) Schematic display

udp tcp ip wvlan llp udp tcp ip eth llp

reliable unreliable reliable unreliable

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Local Testbed

WUGS

SPC/Port4 192.168.40.1 SPC/Port6 192.168.60.1 SPC/Port5 192.168.50.1 145 145 PC4 192.168.40.10 100 41/42 100 51/52 PC5 192.168.50.10 PC6 192.168.60.10 156

WUGS

146 156 146 100 61/62

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Support tool

WUGS

Problems of wireless access

• fast (≈ ms) changing environment
• repeatability of tests

different kind of losses for each test

• comparability of results

Solution: Soft link device

• simulation of link outages
• rate limitation
• packet drops (single or bulk)
• link delays
• re-ordering of packets
• virtual device (Linux based)
• access to parameters using IO-controls

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WUGS

THANK YOU

FOR YOUR ATTENTION!

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