Site Coordinator Training: VC by VC

1. Site Coordinator Training:VC by VC Megan Troyer Technology Coordinator The Ohio State University

2. Peanut Gallery • We are joined by a local as well as a remote audience hosted by OSCnet. • Bob Dixon Megaconference emcee is here to share his experiences • Nicholas Thompson will be presenting a few sections • This session is only as good as you make it, please chime in with your stories, experiences and questions • There are no bad questions!

3. What is videoconferencing? • A real-time, two-way exchange of information between two or more geographically disperse locations using audio, video and sometimes data • It is not web conferencing, video chat, web casting, or streaming

4. Different Technologies • Standards-based: • H.320: videoconferencing on ISDN lines • H.321: videoconferencing using ATM connections • H.323: videoconferencing over packet-based networks i.e. IP • SIP: multimedia multicast transmissions over IP • Currently used more in Voice over IP transmissions, but moving into the videoconferencing world • MPEG2

5. Different Technologies • Not Standards-based: • Access Grid (AG) • Virtual Room Videoconferencing System (VRVS) • DVTS • Most of these technologies have created or are creating interoperability with H.323

6. Conferencing Live Like a telephone call Two-way Call up and answer Broadcasting Live or on demand Like watching television One-way Tune-in or enter URL Streaming Webcasting Conferencing vs. Broadcasting

7. Standards • The United Nations subcommittee International Telecommunications Union-Telecommunications sector ratifies standards for real-time communications technologies • Multiple parties and vendors get input on how the standards are ratified and what gets included

8. H.320 ISDN Special Room High installation cost for connectivity lines Expensive connectivity costs Charges to maintain lines Professional operator Centrally scheduled and administered H.323 IP Any room with high speed Internet connectivity No connectivity cost once you pay your ISP Simple, user-friendly to operate Decentralized control H.320 ISDN vs. H.323 IP

9. The H.323 Standard • H.323 is an umbrella standard that encompasses standards for • Audio • G.711, G.722, G.722.1, G.723.1, G.728, G.729 • Video • H.264, H.263, H.261 • Data • H.239, T.120 • Others: Call Control, Directories

10. A Note on Video Algorithms • H.261 is the oldest of the standards • ALL H.323 and H.320 endpoints can handle this algorithm • H.263 is newer • Most newer H.323 and H.320 endpoints can use this algorithm • H.264 is the newest • Only the newest H.323 endpoints use this algorithm

11. Why is this important? • With each new video codec/algorithm come a better means of processing the video • Each new codec provides better quality video at lower speeds • This means that a 768 kbps call using H.261 video looks as good as a 384 kbps call using H.264 video • This can make a satellite-based videoconference look just as good as land-line

12. Pieces of an H.323 System • Network • The backbone of any H.323 call • Gatekeepers • A control device for H.323 components • Multipoint Control Units (MCUs) • Special network devices that allow more than two sites to connect at the same time

13. A note about H.239 • H.239 is the standards-approved means of doing “duo-video” or “people+content” • This allows for VGA content to be transmitted through the videoconference at native 1024x768 resolution

14. Pieces of an H.323 System • Gateways • Devices that convert other standards to H.323 • Terminals/Endpoints • This is how any site joins an H.323 videoconference • Streaming/Archival • Bringing content to those that cannot attend either due to time constraints or no H.323 equipment

15. The Network The backbone for successful conferencing

16. Wiring and Station Cables • Common practice is unshielded twisted-pair (UTP) according to the specs: • CAT 3 [old] supports 10 Mbps Ethernet (10base-T) • CAT 5 [modern] supports 10base-T, 100 Mbps (100base-TX) and 5e supports 1000 Mbps (1000base-T) Ethernet • CAT 6 [new] supports CAT 5 applications +

17. Wiring and Station Cables • Actual wire used and quality of installation may vary widely – know your wiring! • Important to consider the station cables • Don’t use sub-CAT 5 station cables for 100 Mbps connections. • Silver Satin telephone line cords are not CAT 5. • UTP and florescent lighting.

18. Ethernet LAN • 10 / 100 / 1000 Mbps • Full- and Half-Duplex • Half-duplex: send or receive, one at a time (listens for collision). • Full-duplex: send and receive simultaneously (does not listen for collision). • 10 Mbps Ethernet supports half-duplex; full-duplex is not consistently implemented. • 100 Mbps supports half- and full-duplex. • Modern devicescan auto-sense speed and duplex.

19. LAN: Switches vs. Repeaters • Repeaters (hubs) are old technology. • A repeater sends (repeats) packets that are incoming on one port, out all other ports (I know you’re out there somewhere!). • Can only operate in half-duplex mode. • Bandwidth and jitter provided to any single device is highly dependent on the LAN traffic.

20. LAN: Switches vs. Repeaters • Switches are the way to go • A switch learns the MAC addresses of the devices connected to it, and sends packets directly and only to the target end-point. • Provides much more consistent bandwidth and latency (low jitter). • A well-designed switched LAN is important for videoconferencing. Repeater-based LANs should be upgraded to switched for videoconferencing!

21. LAN: Ethernet Duplex Mismatch • “One of the most common causes of performance issues on 10/100Mb Ethernet links is when one port on the link is operating at half-duplex while the other port is operating at full-duplex.” • http://www.cisco.com/warp/public/473/3.html

22. LAN: Ethernet Duplex Mismatch • “There is a silent performance-killer out there, one so inconspicuous that it is hardly ever looked for or even suspected. You could suffer from it and never know it, as it robs a site of performance but not connectivity. This performance-killer has a name: Ethernet duplex mismatch.” • http://www.hostingtech.com/nm/01_01_mismatch.html

23. LAN: Ethernet Duplex Mismatch • If one end of a connection (device or Ethernet switch) is set for auto-negotiation, and fails to see auto-negotiation at the other end, the former sets itself to the default, half-duplex. • Auto-negotiation can sometimes fail, even when both sides are set to auto (although this isn’t as prevalent as in the past).

24. LAN: Duplex Mismatch Detection • Microsoft Windows doesn’t display the auto-negotiated duplex setting. • Some routers re-negotiate auto-speed or auto-duplex, which can introduce jitter.

25. LAN: Ethernet Duplex Mismatch

26. LAN: Duplex Mismatch- Prevention • Our recommendations: • Don’t use hubs for videoconferencing • If building wiring is sub-CAT 5, then set switch ports to 10/half • If building wiring is CAT 5 or better, then set switch ports and devices to 100/full if supported on switch and device.

27. Router • Provides interface to the WAN. • Intranet, commercial Internet, and Internet2 connections. • Typically, every networked device at an Internet2-connected institution has connectivity to Internet2.

28. WAN Segments

29. Indiana University Abilene NOC Weather Map

30. Traffic on the Network • Typical university today: • IP • TCP • UDP

31. Traffic on the LAN • Unicast : one-to-one • Multicast: one-to-many • Broadcast: one-to-every

32. Unicast • Most common traffic • Common applications: mail, Web browsing, file transfer, etc.

33. IP Multicast • A one-to-many mode of transmission • Network numbers 224.0.0.0 through 239.255.255.255 are reserved for multicast. • Examples of multicast applications: • Vic/rat videoconferencing • Centralized PC software administration tools such as Symantec Ghost

34. IP Multicast – Leak Problems • Beware: high rates of unpruned multicast can adversely affect videoconference performance. • Use a network traffic and protocol analyzer to identify this problem.

35. Broadcast • A one-to-every mode of transmission • Used by network protocols including ARP and IPX, NetBIOS system discovery, and name resolution. • All devices on the network must process every broadcast packet; high broadcast rates can divert processing capacity. • If the broadcast domain is too large or unusually active, the activity required at the end-point to deal with the broadcasts could diminish performance.

36. Broadcast • A healthy network should have less than 100 broadcast packets per second. • Check using a network traffic and protocol analyzer tool.

37. Unicast Video Broadcasting

38. Multicast Video Broadcasting

39. Firewalls • A firewall is a network node that acts to enforce an access control policy between two networks, e.g., between a university intranet and the commercial Internet. • Used to secure IT resources against external attacks and break-ins. • Network-layer firewalls typically make their decisions based upon port numbers and source/destination addresses. • Application-layer firewalls act as proxies.

40. Firewalls • H.323 uses the IP ports: • Statically-assigned TCP ports 1718 – 1720 and 1731 for call setup and control. • Dynamically-assigned UDP ports in the range of 1024 – 65535 for video and audio data streams. • Firewalls don’t allow unrestricted ports. Typical modern firewalls and H.323 don’t get along so well.

41. Firewalls – Solutions for H.323 • [bad; non-scaleable] Allow unrestricted ports for specific, known, external IP-addresses. • [better, but still not so good] Use feature of some videoconferencing clients to confine dynamic ports to a specific, narrow range. • [OK, but extra admin work] Use an H.323 application proxy. • [best] Use a firewall that snoops on the H.323 call set-up channels (static ports) and opens ports for the audio/video (dynamic ports) as needed.

42. NATs • Allows multiple computers behind the NAT to share one external network address. • Uses: • Alleviate shortage of IP addresses • Security – obscures view of the network from outside • Flexible network administration • Not commonly used at universities on the campus level. Used somewhat in corporations. Common in small offices and at home – behind DSL, cable modem, or ISDN network service.

43. NATs • Difficult to use H.323 behind NATs • Some videoconferencing terminals provide features to work with NAT. Refer to videoconferencing terminal documentation. • Think of your private IP address like an internal telephone number. An endpoint outside of your organization will not know what to do with it. • 10.x.x.x • 192.168.x.x • 172.16.x.x-172.31.x.x

44. Solution Caveats • Though many manufacturers will have Firewall/NAT traversal solutions built in to their devices, these are proprietary vendor-specific solutions • Polycom’s “Use Defined Ports” only works on point-to-point Polycom to Polycom calls • H.460.17, 18, 19 are standards-based solutions ratified into H.323 to standardize Firewall and NAT traversal solutions

45. H.460.17/18/19 Firewall Traversal • Works by creating pin-holes • Products that follow it • Polycom V2IU©* • Tandberg Expressway© • Radvision PathFinder™ • Micromethod Horizon™ * Only follows the .18 portion of the whole standard

46. H.460.17/18/19 Firewall Traversal • Solutions that do not follow the standard • Direct Packet Research S.T.N.S© • Visual Nexus

47. Latency • Latency is the time required for a packet to traverse a network from source to destination. • Components of latency include: • Propagation delay: the time it takes to traverse the distance of the transmission line; controlled by the speed of light in the media; rule-of-thumb: 20ms San Francisco to New York.

48. Latency • Transmission delay: the time it takes for the source to put a packet on the network. Rule-of-thumb for general network devices: < 1ms. • For H.323 this includes time to encode/decode the video • Store-and-forward delay: the cumulative length of time it takes the internetworking devices along the path to receive, process, and resend the packets. Rule-of-thumb: variable, and depends upon network load.

49. Latency • Rule of thumb: • A one-way delay of: • 0 – 150 ms provides excellent interactivity • 150 – 300 ms is OK • 300 – 400 ms is bad • 400+ ms is unacceptable • Satellite delay in the “unacceptable” range, but you will find that you get used to the delay

50. Jitter • Jitter is variation in latency over time. • If the endpoints are on switched LANs, then the primary source of jitter is variation in the store-and-forward time, resulting from network load. • H.323, particularly audio, is adversely affected by high levels of jitter. • What is high? Rule of thumb? No statistics