Xiphos.ca Charlie Younghusband XipLink Product Manager Xiphos Technologies Xiphos’ Work with SCPS-TP & applications and interest in CisLunar Introducing.

xiphos.ca

Charlie Younghusband

XipLink Product Manager

Xiphos Technologies

Xiphos’ Work with SCPS-TP & applications and interest in CisLunar

Introducing XipLink

xiphos.ca

About Xiphos and XipLink

Relatively small engineering company located in Montreal, Quebec > ~80% of employees with a minimum

Bachelors in Engineering in various disciplines

Research & Development: Aerospace applications is the primary technology driverRobust basis

Incorporated in 1996

xiphos.ca

Quick History

Involved in a telehealth project moving large data files over satellite and ran into TCP over satellite issues Did tuning Developed our own TCP->UDP transport protocol

using the framework of another technology we had Independently, we had looked at SCPS for some

onboard work, did a limited SCPS-NP implementation Approached and received partial funding from the

CSA for a high performance implementation of SCPS-TP in 2000

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Xiphos SCPS-TP -> XipLink

• Implementation of SCPS-TP became basis for XipLink – “link performance enhancement technology for stressed communication links”• Integrates other optimizations like data compression

and HTTP Acceleration• Can meet or beat all competition

• SCPS’ design is very practical to directly scale terrestrial communications to satcom and space

• SCPS-TP implementation implemented differently than RI. Does T/TCP, does not do Best Effort Transport Service (BETS). More optimized for Satcom

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SCPS-TP

Uses sender side only algorithms or negotiates capabilities (extensions to normal TCP) through TCP options at connection setup

Can go end-to-end or a proxy gateway architecture Very flexible architecture. Easy to change, can be done

adhoc or ‘mixed’, legacy network deployment benefits Big reason for its adoption by US Military

Flexible for integrating other technologies from Internet or custom developed while maintaining architecture

Ease of analysis, IP transparency, when not using rate control can be QoS engineered

xiphos.ca

SCPS-TP

Sending congestion control Rate control: bandwidth known TCP Vegas: variable, shared links

Selective Negative Acknowledgments (SNACK) more responsive and efficient

TCP Header Compression: removes redundancy TCP for Transactions: skips 3 way handshake ACK frequency reduction to limit return path

bandwidth

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SCPS-TP Activities

Selling our own “XipLink Gateways” installed bracketting satellite links

Licensed into vendor satellite terminals Specialized projects in defence Used for end-point communication to on-

board spacecraft nodes

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Xiphos SCPS-TP

Used BSD Network stack as a basis Low level implementation in kernel on Linux

and VxWorks well Many optimizations for dynamic buffering,

managing 10,000 connections+, burst connection opens, really advanced rate control algorithm, QoS options

xiphos.ca

Related Projects I

Dynamic bandwidth satellite terminals strong focus for maximizing bandwidth utilization and distribution among many nodes

Many ways of managing access to the link Side channel requests, dedicated slots, ALOHA etc. DVB-RCS (Return Channel via Satellite) is a

standard growing in recognition The general ‘volume’ based capacity allocation

results in ~1.5 second RTT. Design expecting 1.8 seconds. Increased load can increase this.

Going through standardization right now.

xiphos.ca

Related Projects II

Doing our own project via SCPS-TP to UAV Do it in combination with UDP telemetry data

streams Other projects by US Primes for aircraft

communications Choice or varying communication links, paths

Possibly more than one satcom hop also high delay, possible high BER

SCPS-TP will fly on a microsatellite launching in June

xiphos.ca

SCPS-TP to CisLunar

Many of the same issues. IP/SCPS-TP could used but could really use

updates Other SCPS layers future doubtful Evaluation of necessary extensions, IPV6 etc We will be looking at other complementary

environments like DVB-RCS – session layer/inter gateway communication

Further published study work

xiphos.ca

xiphos.ca

Charlie Younghusband

XipLink Product Manager

[email protected]

514-848-9640 x221

#800 - 3981 St. Laurent Blvd.

Montreal, Quebec, Canada

http://www.xiplink.com/

IP Communications through stressed links.