
d7d514948e8a84599ad34d84be3f094d.ppt
- Количество слайдов: 38
How To Successfully Implement IP Video EDUCAUSE 2002 OCTOBER 2, 2002 ALAN STILLERMAN ED STOCKEY
Copyright Alan Stillerman and Ed Stockey, 2002. This work is the intellectual property of the author. Permission is granted for this material to be shared for non-commercial, educational purposes, provided that this copyright statement appears on the reproduced materials and notice is given that the copying is by permission of the author. To disseminate otherwise or to republish requires written permission from the author.
AGENDA • • HISTORY AND BACKGROUND QUALITY OF SERVICE (Qo. S) FIRE WALLS & PROXYS GATEKEEPERS/GATEWAYS DIAL PLAN CODECS DIRECTORY SERVICES REGISTRATION/SCHEDULING
IHETS: Basics • Indiana Higher Education Telecommunication System • Consortium of all accredited public and private postsecondary institutions in Indiana • Created by enabling legislation in 1967 • INDNET begun 1995 • IHETS becomes Manager of the Indiana Telecommunications Network 1997 • ITN serves all public institutions – this includes: Higher Education, K-12 schools, Public Libraries, State, County and Local government • Total Sites Connected to ITN > 1, 700
BACKGROUND • TWO-WAY INTERACTIVE VIDEO – H. 323 – IP VIDEO 2001 • MCU TESTING – FALL 2000 RESULT: THEY ACTUALLY WORK!! • RECOMMENDATION: Accord MGC 100 • NEED TO LOOK AT THE VARIOUS ISSUES AND COMPONENTS NEEDED TO IMPLEMENT H. 323 ON THE NETWORK – IP VIDEO TASK FORCE
Qo. S (Quality of Service) • What is Qo. S – Set of techniques to manage network resources which enables the network to differentiate and handle traffic based on policy • Why implement Qo. S – Provide consistent, predictable data delivery by managing delay(latency), delay variation(jitter), bandwidth and packet loss • Bandwidth is not the complete solution
Quality of Service • Challenges providing Qo. S for IP video – Head of line blocking (HOLB) – IP video uses UDP (universal datagram protocol) for transport of video and only uses TCP for control data – cannot resend lost video packets – Video uses large, variable length packets
Video Conferencing Traffic Packet Size Breakdown (CIF) 384 kbps Video Call 1% 65 -128 Bytes 37% 1025 -1518 Bytes 8% 257 -512 Bytes 34% 129 -256 Bytes 20% 513 -1024 Bytes VVT-230 2917_05_2001_c 1 © 2001, Cisco Systems, Inc. All rights reserved
Provisioning Video Data Rate + 20% = Bandwidth Required Video Data Voice Routing etc. Video Data Rate BW Required 128 kbps = 153 kbps 384 kbps = 460 kbps < 33% of Link Capacity < 75% of Link Capacity “Recommendations” VVT-230 2917_05_2001_c 1 © 2001, Cisco Systems, Inc. All rights reserved 512 kbps = 614 kbps 768 kbps = 921 kbps 1. 5 Mbps = 1. 8 Mbps
Quality of Service Approaches • Big Pipes • Qo. S • Both
Qo. S – How We Do It • ACLs (access control lists) – to identify traffic and set IP precedence. For video and/or voice precedence is set to 5. • Service policies push traffic into: – Low latency queuing (Priority queue) – Reserve bandwidth for RAS – Data queues which use RED • Caveat – hardware limitations – example: Cisco 25 xx routers
Qo. S • Bandwidth guarantees for a T 1 (1. 544 Mbps): • • 512 kb/s for video 128 kb/s for voice 64 kb/s for SNA Remainder for everything else
FIRE WALLS • Used to block traffic by disabling ports that allow traffic to come in to a users intranet. • Usual strategy – Incoming: Block everything coming in. Open ports only as necessary based on need. – Outgoing: Allow everything. • H. 323 Video requires the following ports to be open in both directions to allow for optimal two way videoconferencing. – 1718, 1719, 1720
PROXYS • Allows a user to be anonymous to the outside world. • Acts as a filter for incoming traffic. • Requires a proxy server on both sides of firewall for H. 323 video
FIRE WALLS • Tested and Certified – CISCO PIX 6. 2 • Currently Being Tested – – – Checkpoint Gauntlet Cisco IOS Firewall Firebox Linux Firewalls • Firewalls that will not work with H. 323 – Novell Border Manager
Difference between Gatekeepers and Gateways • Gatekeeper • Gateway – IP based – Address Resolution – Layer 3 – Bandwidth Management • Call Admission Control (CAC) – Call forwarding – Technology Prefixes – Exist in hierarchies – Can transcode between ISDN, ATM and IP – Address Resolution – Layer 2
Limitations of Gatekeepers • 4 Levels of Hierarchies • Can have no more than 6 Forwarded Location Requests (LRQ) without effecting latency
IP Video Gatekeeper Hierarchy • Institutional Gatekeepers – 2 levels of hierarchy • Gatekeepers located on node routers • IHETS Directory Gatekeeper • National Gatekeeper • International Gatekeeper
Why Do We Need A Dial Plan? • To support legacy ISDN and ATM codecs • To enable a seamless connection between codecs in various parts of the state and across the nation • To let people off net to be able to call IP codecs on net (Inbound calls) • USER FRIENDLY
INDnet Dial Plan • E[T]ZZZNNNNNNN • • E = Exit Zone Prefix. “ 1” (Optional) T = Technology Prefix (Optional) ZZZ = Area Code NNNNNNN = Seven digit E. 164 number • Based on North American Numbering Plan (NANP)
Dial Plan • Dialing between all protocols supported • 10 digit E. 164 number required in order to register with IHETS core gatekeeper • First three numbers must match a valid area code as defined by NANP • Next seven digits can be either: a user defined number or a valid seven digit Direct Inward Dial (DID) number such as the phone number on their desk
Dial Plan • Seven digit number on desk ensures uniqueness of 10 digit number within an area code • Technology prefix required in order to dial off net to ISDN endpoint • Automatically scales to national and international dial strings based on E. 164 • Allows for future migration to ENUM standard when implemented
Common Failures of Video Calls • Unit has not been rebooted for several days • PC NIC is not set for 100 Mbps – Full Duplex • LAN/WAN is not set for 100 Mbps – Full Duplex • Video call is not set up through a gatekeeper • Gatekeeper not properly configured • ISDN Cloud • Internet Cloud • CSMA/CD on 10 Mbps – Half Duplex
Codec Recommendations • That a vendor have both a desktop (PC based) and a room system in their product line • Support interoperability • Ease of Support • Financial considerations • Based on IPVTF
Codec Recommendations • Room Systems – Polycom Viewstation FX (Appliance Based) – VCON Media Connect 8000 (PC Based) • Desktop Systems (PC Based) – Polycom Via. Video – VCON Vi. GO • Based on IPVTF
DIRECTORY SERVICES Click To Meet. TM • Connects Point-to-Point any protocol – IP – ATM, IP – ISDN, ATM - ISDN • Creates multipoint conferences on the fly • Can schedule Point-to-Point or multipoint conferences in the future • Sends out e-mails notifying end users of upcoming meetings • Can program all calls to go through a gateway or bridge
DIRECTORY SERVICES Click To Meet. TM • Continuous presence built in • Will handle streaming media • Supports firewall NAT/proxy/VPN transversal • Connects to a gatekeeper • Version 3 uses Microsoft’s Active Directory for user accounts – LDAP support provides the capability to support connectivity to external, 3 rd party data stores like Novell’s e. Directory, Sun ONE Directory Server (formerly i. Planet LDAP Server) and Netscape’s Directory Server
Dialing Made Simple Courtesy First Virtual Communications, Inc.
Scheduling Made Simple Courtesy First Virtual Communications, Inc.
REGISTRATION AND CERTIFICATION • http: //www. ihets. org/network/ipvi deo/ctm/index. html • Allows Qo. S to be enabled on the edge and core routers • Provides data for directory entry • Verified by Point-to-Point and multipoint test calls
How To Reach Us Ed Stockey Assistant Director, Product Research estockey@ihets. org 317 -263 -8943 Alan Stillerman Senior Product Research Analyst astiller@ihets. org 317 -263 -8888