Post on 02-Jan-2016
description
Setup and Evaluate Quality of Service of VoIP on SCOLD Systems
Sherry AdairHakan Evecek
Elizabeth Gates
GOALS
1. Monitor a staged SCOLD attack.2. Analyze the VoIP related protocols including
SIP, H.323, and RTP.3. Discuss the applications used: SJphone,
NetMeeting, MSN, and HMP conferencing.4. Use the Agilent SW Edition Advisor J1955A5. Show the configurations used for the
experiments.6. Provide network errors encountered.7. Conclusions.
SCOLD
The SCOLD project explores the use of alternate routes when internet security is threatened with an attack on the primary route.
Voice-over-IP technology transfers voice signals in data packets over IP networks in real-time. It uses some other protocols like TCP, Internet Protocol (IP), User Datagram Protocol (UDP), Real-Time Transport Protocol (RTP), RTCP or RTCP-XP.
Some of the benefits using VoIP:• Cost Savings.• Open standards and multivendor interoperability.• Integrated voice and data networks.
WHAT IS VoIP?
PROTOCOLS
Call Control Protocols: They setup and tear down a call across a data network. Each have different rules.
Gateway Control Protocols: Uses central coordinators to control events and manage connections. Media Control Protocols: They manage the traffic that requires
playback at the receiving application in a time sensitive mode.
PC to PC. PC-to-Telephone calls. Telephone-to-PC calls. Telephone-to-Telephone calls via the Internet. Premises to Premises. Premises to Network. Network to Network.
VoIP MODES OF OPERATION
Used for multimedia over LAN. It provides component description, signaling procedures, call control, system control, audio/video codec and data protocols.
Components are terminal, gateway, multimedia control unit to decide the media stream path and gatekeeper.
Supports G.711, G722, G723 audio and G728, G729 video codecs, H.225 packet and message format, H.245 channel negotiation and exchange and T.120 data sharing protocols.
H.323
Used for multimedia sessions like H.323. SIP is a simple, text based request, open, and well-
defined interface encouraging application Level signaling protocol.
Allows setting up, modifying terminating sessions with one or more participants.
Supports user location, call setup, call transfers, mobility by proxy, multi point control unit for different connections .
Carries session description and setup. It supports session management.
SESSION INITIAL PROTOCOL
Call establishment is straightforward and flexible. Syntax is very similar to HTTP. It can be Multiple
Purpose internet mail (MIME) or extensible markup language (XML)
Sip components are redirect server, proxy server, user agent, registrar, SIP Server and location server.
Protocols used to transfer packets. UDP, small packet size. TCP, there will be multiple signal flow due to the
TCP structure. SCTP, In the order with respect to the other
messages within the same stream.
HOW SIP OPERATES?
Real-Time Protocol Delivery of real-time information
Services Payload type ID Sequencing Timestamping
PayLoad Types: Audio Video Telephony signals Text conversation
RTP (REAL-TIME PROTOCOL)
H.323 vs. SIPBelow are call samples from SIP and H.323. Easy syntax, support mobile users and assign the transactions to command sequence makes SIP preferable to the other protocols.
Q.931 SETUP
Q.931 CONNECT
INVITE
200 OK
ACK
Terminal Capabilities
Terminal Capabilities
Open Logical Channel
Open Logical Channel
H.323 SIP
Destination address (test@uccs.edu)
Media capabilities
Media transport address (RTP/RTCP receive)
VoIP APPLICATIONS
SJphone: PC voice client to speak over internet uses SIP and H.323 protocols
NetMeeting: Allows point to point audio communication using H.323
MSN: Allows you to make phone calls over the internet using SIP
Intel NetStructure Host Media Processing (HMP): Conference host for up to120 H.323 and SIP clients
AGILENT ADVISOR SW
Software protocol analyzer
Designed to troubleshoot and analyzer Ethernet and Fast Ethernet networks
Decodes major protocols for all 7 layers
Runs on Windows 98/2000/NT 4.0 with NIC or PCMCIA network adapter but not on UNIX.
%Utilization, total # of frames, packet sizes IP low time to live, broadcasts, and multicasts
The network is running slowly and you want
to know why.• How many stations are active?• How many connections are there between
stations?• What protocols are being used?• Are errors being generated?
View: Connection Statistics Measurement
HOW BUSY IS THE NETWORK?
You want to know if the majority of the trafficis coming from a few stations.Who are the top talkers on the network?
Who are the active stations? Which connections are transmitting the most
traffic? What protocols are being used?
View: Expert Analyzer View
WHO ARE THE TOP NETWORK TALKERS ?
Are alert, warning, or normal protocol events occurring?
What protocols are having problems? Who is causing the problems?
View: Connection Statistics Measurement
WHAT ARE THE NETWORK PROBLEMS?
TESTBEDS
Simple two way communication using the network then the internet.
Conferencing using NetMeeting then Intel’s Netstructure Host Media Processing Demo.
Simple SCOLD attack on a two way
communication then on a conferencing call.
A simple two-way phone conversation over the
network.Wait.uccs.edu Wind.uccs.ecu
sjphoneanalyzer
sjphone
Through SJphone, Wind calls Wait using Wait’s IP address.
Wait responds through SJphone.
Using microphones and speakers, we converse on Wait and
Wind.
dilbert.uccs.edu laptop
Wind.uccs.edu
NetMeetingAdem
A NetMeeting call over the network
NetMeetingHakan
NetMeetingSherry
Adem calls Hakan, Hakan accepts.
Sherry calls both Adem and Hakan, both accept.
Using microphones and speakers a three-way
conversation is held.
A SCOLD ROUTE
wait.uccs.edu
wind.uccs.edu
vinci.uccs.edu
sjphoneanalyzer
SCOLD proxyEthereal
sjphone
Indirect Route
Indirect Route
Direct Route
An attack on the direct route causes SCOLD to find an indirect route.
In the lab, this was performed by hand using Public IP addresses for the Direct Route and Private IP addresses for the Direct Route.
CONCLUSIONS
Manual test In the real world this setup will be automatic, not manual.
IP indirect routing tunnel The voice connection was blocked on the indirect route but was easily reestablished when the physical connection was reestablished.
SCOLD delay Network connection delay was not measurable with this experiment because the primary and secondary paths were manually switched and there was only one extra hop.
References Chow C.E., Cai Y., Wilkinson D., Secure Collective Defense (SCOLD)
Network http://cs.uccs.edu/~scold Network World, November 17th Volume 20 page: 31, RTCP XR measures VoIP performance. Improving QoS of VoIP over WLAN :
http://cs.uccs.edu/~msoliman/cs522/docs/QoS%20of%20VoIP%20over%20wlan.pdf Daniel Collins: Carrier Grade Voice over IP, 2nd Edition. Daniel Minoli, Emma Minoli : Delivering Voice Over IP Networks, 2nd Edition. Igor Faynberg, Lawrence Gabuzda, Hui-Lan Lu : Converged Network and
Services. RFC 2543 SIP : Session Initiation Protocol : http://www.faqs.org/rfcs/rfc2543.html Uyless Black, Voice Over IP – 2nd Edition H.323 Protocol Suite: http://www.protocols.com/pbook/h323.htm Please refer to the report for rest of the references from the link below: http://cs.uccs.edu/~cs522/studentproj/projF2003/hevecek/