Setup and Evaluate Quality of Service of VoIP on SCOLD Systems Sherry Adair Hakan Evecek Elizabeth Gates
GOALS • Monitor a staged SCOLD attack. • Analyze the VoIP related protocols including SIP, H.323, and RTP. • Discuss the applications used: SJphone, NetMeeting, MSN, and HMP conferencing. • Use the Agilent SW Edition Advisor J1955A • Show the configurations used for the experiments. • Provide network errors encountered. • Conclusions.
SCOLD The SCOLD project explores the use of alternate routes when internet security is threatened with an attack on the primary route.
WHAT IS VoIP? 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-XR. Some of the benefits using VoIP: • Cost Savings. • Open standards and multivendor interoperability. • Integrated voice and data networks.
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.
VoIP MODES OF OPERATION • 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.
H.323 • 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.
SESSION INITIAL PROTOCOL • 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.
HOW SIP OPERATES? • 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.
RTP (REAL-TIME PROTOCOL) Real-Time Protocol • Delivery of real-time information Services • Payload type ID • Sequencing • Timestamping • PayLoad Types: • Audio • Video • Telephony signals • Text conversation
H.323 vs. SIP Below 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. H.323 SIP Q.931 SETUP INVITE Destination address (email@example.com) Q.931 CONNECT 200 OK Terminal Capabilities Media capabilities Terminal Capabilities ACK Open Logical Channel Media transport address (RTP/RTCP receive) Open Logical Channel
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
HOW BUSY IS THE NETWORK? 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
WHO ARE THE TOP NETWORK TALKERS ? You want to know if the majority of the traffic is 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
WHAT ARE THE NETWORK PROBLEMS? • Are alert, warning, or normal protocol events occurring? • What protocols are having problems? • Who is causing the problems? View: Connection Statistics Measurement
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 sjphone analyzer 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.
A NetMeeting call over the network dilbert.uccs.edu laptop NetMeeting Sherry NetMeeting Adem Wind.uccs.edu NetMeeting Hakan • 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 Indirect Route wait.uccs.edu vinci.uccs.edu SCOLD proxy Ethereal sjphone analyzer Indirect Route Direct Route wind.uccs.edu sjphone • 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/