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-XR.

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

DATA FROM ANALYZER

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.

NETWORK ERRORS

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/