SCTP%20Research

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SCTP Research
Prof. Paul Amer Prof. Phillip Conrad Armando
Caro Jerry Heinz Jana Iyengar Sourabh
Ladha Keyur Shah Len Armstrong Dr. Sam
Chamberlain (ARL)
CISC Department
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Who are we?
Armando Caro
PhD student (final year!) Summer Internships
Telcordia (00,01), Nokia (02) Primary author
of ns-2 module for SCTP (downloaded to gt 400
sites) Contributor to tcpdump module for SCTP
Paul Amer

• UD Faculty 1979- present
• Research focus transport layer protocols, data
  compression, formal specification
• An Extension to TCP Partial Order Service,
  RFC1693, Nov 94
• Transport Layer Protocols Survey and Tutorial,
  ACM Computing Surveys, 31(4), Dec 99

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Outline

• Research
• Marketing

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Research - Current Sponsor
U.S. Army Research Lab Collaborative Technology
Alliance (CTA) Communication Networks

• 76M, 2001-2009

• Industry Telcordia, BBN, BAE Systems, General
  Dynamics, NAI Labs
• Academia UDelaware, UMaryland, Johns HopkinsU,
  Georgia Tech, Princeton, Morgan State, Clark
  Atlanta, UMinnesota, Cornell, UC-Riverside,
  WashingtonU, UMichigan, New Mexico State

• Research Topics
• Survivable Wireless Mobile Networks (SCTP)
• Signal Processing for Communications-on-the-Move
  
• Secure Jam-Resistant Communications
• Tactical Information Protection

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SCTP research projects1. multihoming
failover/retransmission policies2. multihoming
for concurrent multipath transfer3.
multistreaming to enhance file transfer4.
unordered/partial order delivery5. controlled
partial reliability
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Multihoming
port
Application
132 (IANA)
SCTP
IP addresses
...
IP
Link
...
...
Physical
...
failover for persistent on-the-move sessions
concurrent multipath transfer
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Multihoming with mobility
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Current retransmission policy

• If peer is multihomed, retransmit to an alternate
  destination
• Why the alternate destination?
• Attempts to improve chances of success
• No prior research to demonstrate benefits
• We found that this policy doesnt provide best
  performance in many circumstances
• Not enough traffic to accurately update alternate
  destinations RTO so timeouts are LONG!

A. Caro, P. Amer, R. Stewart. Transport Layer
Multihoming for Fault Tolerance in FCS Networks.
MILCOM 2003, Boston, October 2003
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Potential Solutions

• Solution 1 Retransmissions to same destination
• Pro uses destination with accurate RTO cwnd
  benefits for primary
• Con fewer successful transmits if primary failed
• Solution 2 Original Heartbeat after RTO
• Pro immediate opportunity to measure RTT after
  RTO backoff
• Con still few samples to estimate alternate RTT
• Solution 3 Original Timestamps
• Pro Karns Algorithm not needed more RTT
  samples on alternate
• Con 12-byte overhead in each packet
• Solution 4 Original Our Multiple Fast
  Retransmit Algorithm
• Pro minimizes number of timeouts
• Con no extra RTT samples on alternate
• Solution 5 combine 1 4

A. Caro, P. Amer, J. Iyengar, R. Stewart.
Retransmission Policies with Transport Layer
Multihoming. ICON 2003, Sydney, Australia,
September 2003.
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Simulation Topology
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(No Transcript)
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SCTP research projects1. multihoming
failover/retransmission policies2. multihoming
for concurrent multipath transfer3.
multistreaming to enhance file transfer4.
unordered/partial order delivery5. controlled
partial reliability
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Concurrent Multipath Transfer (CMT)

• If peer is multihomed, transmit only to primary
  destination
• data not sent to multiple destinations
  concurrently
• CMT should increase net throughput, but
• not clear if it will
• side-effects unknown
• more research needed
• Identified three negative side-effects of CMT
  with SCTP
• proposed three algorithms to eliminate problems
• Currently investigating other performance hurdles
• e.g., due to shared rwnd, shared bottleneck, etc.

J. Iyengar, K. Shah, P. Amer, R. Stewart.
Concurrent Multipath Transfer Using SCTP
Multihoming. Submitted to Hotnets-II, Cambridge,
MA, November 2003.
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Expected
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Expected
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SCTP research projects1. multihoming
failover/retransmission policies2. multihoming
for concurrent multipath transfer3.
multistreaming to enhance file transfer4.
unordered/partial order delivery5. controlled
partial reliability
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Multistreaming
voice
video
tactical info (e.g., gps, supply levels)
images (e.g., maps, radar)
Issues synchronization, congestion control, flow
control
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Multistreaming with priorities

• Reconnaissance Mapping
• image low priority stream
• region of interest high priority stream

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File Transfer Protocol (FTP)
control connection
FTP client
data connection
n1 TCP connections
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FTP over TCP
Server
Client
PORT
200
NLST
SYN
SYN-ACK
ACK
150
DATA
FIN
226
FIN-ACK
PORT
ACK
200
SIZE
213
RETR
SYN
SYN-ACK
ACK
150
DATA
FIN
226
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Using multistreaming in FTP
FTP server
FTP client
control stream
data stream
single SCTP association
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FTP over TCP
Server
Client
PORT
200
NLST
SYN
SYN-ACK
ACK
150
DATA
FIN
226
FIN-ACK
PORT
ACK
200
SIZE
213
RETR
SYN
SYN-ACK
ACK
150
DATA
FIN
226
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Experimental Setup
bandwidth BW delay D
FTP client
Traffic shaper
bandwidth BW delay D

• Bandwidth-delay configurations
• 1Mbps - 35ms
• 256Kbps - 125ms
• 3Mbps - 1ms
• Loss probability 0, .01, .03, .06, .10
• Loss probability distribution uniform

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configuration 1Mbps - 35ms
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configuration 256Kbps - 125ms
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Results

• FTP over SCTP with multistreaming/pipelining
• dramatically reduces end-to-end latency in
  multiple file transfers, and in a TCP-friendly
  manner
• reduces the server load (by decreasing the number
  of connections)
• reduces the network load
• maintains simplicity at the application

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SCTP research projects1. multihoming
failover/retransmission policies2. multihoming
for concurrent multipath transfer3.
multistreaming to enhance file transfer4.
unordered/partial order delivery5. controlled
partial reliability
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Unordered/Partial Order Delivery

• A create event on object A must be communicated
  before a modify event on A. However, the order
  to process create events on objects B and C is
  unimportant. If the create event on A is not
  delivered, we must suspend processing the modify
  on A. However, we are completely free to process
  the create event on B C

Designing Communications Software For Tactical
Wireless Networks, by Thomas McVittie
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Controlled/partial reliability
10 second video 5 frames/sec
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Marketing
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Demand for SCTP

• US Army CTA project
• Dr. James Freebersyser (DARPA Advanced Technology
  Office)
• Future Combat Systems (FCS) Communications
  Project
• Raytheon is leading a team to develop and
  demonstrate a mobile ad hoc network with
  directional antennas on top of a military-quality
  waveform.
• Applications may not use TCP!!
• UD is responsible for putting army applications
  on top of SCTP
• Nokia and Ericsson using SCTP for signaling and
  3GPP
• Nokia already shipping products with SIGTRAN over
  SCTP
• SCTP required for 3GPP
• Boeing investigating SCTP for military satellite
  networks MANETs

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SCTP Interoperability Workshops Bakeoffs
Munich 06/00 12
Research Triangle Park 10/00 22
Sophia Antipolis 04/01 19
San Jose (Connectathon) 02/02 6
Univ. of Essen (Germany) 09/02 20
Univ. of Delaware 06/03 11

• Participation in Bakeoffs ADAX - Cisco
  HP/Compaq - Data Connection - DataKinetics -
  Ericsson - Hughes Software - IBM - Motorola
  Netbricks - Nokia - Open SS7 - Performance
  Technologies - RadiSys - Siemens Spider - Sun
  Microsystems - Telesoft Technologies - Toshiba -
  Ulticom -Wipro
• More than 26 Implementations AIX, FreeBSD,
  Linux, HP-UX, QNX, Solaris, True64 UNIX, IOS
  (Cisco Routers), Mac OS, Windows, more

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Tools, Applications, etc

• Simulators
• Ns-2 (developed at UD)
• OPNET
• Packet sniffers
• Tcpdump
• Ethereal
• Non-telephony applications
• Mozilla web browser
• Apache web server
• OpenSSH client server
• BSD FTP client and server (developed at UD)
• MPEG-4 streamer and player
• Webcam streaming application

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Ns-2 SCTP Module

• gt 400 unique downloads (based on /16 IP
  addresses or DNS suffix)
• Now integrated with main distro
• More than 50 researchers on our mailing list
• Stephan Baucke _at_ Ericsson Research
  (Reiner Ludwigs group)
• Martin Duke _at_ Boeing Phantom Works
  (Tom Hendersons group)
• Michael Tuexen _at_ U of Applied Sciences in
  Muenster (formerly _at_ Siemens)
• HP Labs, Samsung, Telcordia, Lockhead Martin,
• GA Tech, U Oklahoma, U Florida Gainesville, U
  Maryland Baltimore County,
• Papers, magazine articles, IETF drafts
• Alamgir 02, Atiquzzaman 02, Balk 02, Duke
  03, Fu 02, Fu 03, Haddad 02, Madisetti
  02a,b,c, Ye 02
• Course projects
• Professor Mario Gerla _at_
  UCLA
• Professor Li Xiao _at_
  Michigan State University
• Professor A. L. Narasimha Reddy _at_ Texas AM
  University

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Conclusions - Publications
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UDelaware CISCO Collaboration

• Transport layer multihoming for fault tolerance
  in FCS networks, MILCOM 03, Boston, 10/03  
  (Caro, Amer, Stewart)
• Retransmission policies with transport layer
  multihoming, ICON 03, Sydney, 9/03 (Caro, Amer,
  Iyengar, Stewart)
• Making SCTP more robust to changeover, SPECTS
  03, Montreal 7/03 (Iyengar, Caro, Amer,
  Heinz, Stewart)
• Using SCTP multihoming for fault tolerance and
  load balancing, SIGCOMM 02 - Computer Comm
  Review, 32(3), 7/02 (Caro, Iyengar, Amer, Heinz,
  Stewart)
• A two-level threshold recovery mechanism for
  SCTP, SCI 02, 7/02 (Caro,
  Iyengar, Amer, Heinz, Stewart)
• SCTP congestion window overgrowth during
  changeover, SCI 02, Orlando, 7/02 (Iyengar,
  Caro, Amer, Heinz, Stewart)
• Transport layer multihoming for fault tolerance
  in FCS networks, 2003 Army Research Lab
  Symposium, College Park, MD, 4/03 (Caro, Amer,
  Stewart)
• Transport layer load balancing in FCS networks,
  2003 Army Research Lab Symposium, College Park,
  MD, 4/03 (Iyengar, Amer, Caro, Stewart)

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UDelaware CISCO Technical Reports

• SCTP and TCP variants congestion control under
  multiple losses, TR2003-04, 3/03 (submitted to
  CCR) (Caro, Shah, Iyengar, Amer, Stewart)
• Retransmission policies with transport layer
  multihoming, TR2003-05, 3/03 (Caro, Amer,
  Iyengar, Stewart)
• Making SCTP more robust to changeover, TR2003-01,
  7/02 (Iyengar, Caro, Amer,
  Heinz, Stewart)
• Concurrent multipath transfer using SCTP
  multihoming, (in preparation) (Iyengar, Shah,
  Caro, Amer, Stewart)

UDelaware - CISCO Internet Drafts

• Stream Control Transmission Protocol (SCTP)
  Implementers' Guide (Stewart, Ong, Rodriguez,
  Poon, Conrad, Caro, Tuexen)
• Preventing SCTP congestion window overgrowth
  during changeover (Iyengar, Amer, Stewart)

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Other UDelaware publications on SCTP

• SCTP A standard for robust Internet data
  transport, IEEE Computer (to appear) (Caro,
  Iyengar, Amer, Heinz, Ladha, Shah)
• Improving file transfer in FCS networks, MILCOM
  2003, Boston, 10/03 (Ladha, Amer, Caro, Iyengar)
• Priorities in SCTP Multistreaming, CISC Dept
  TR2004-01, 8/03 (Heinz - MS Thesis)
• Improving multiple file transfers using SCTP
  multistreaming, CISC Dept TR2003-06, 5/03
  (Ladha, Amer)