AREN by vivi07


									Experiences with Unicast/Multicast Tutorials and International Classes at the University of Alabama in Huntsville
Robert L. Middleton, P.E. Senior Research Engineer University of Alabama in Huntsville

Richard T. Bagwell Senior Network Engineer Alabama Research and Education Network

• The Huntsville based National Center for Children’s Advocacy wanted an Internet based replacement for their Satellite based Tutorials • UAH Internet based streaming video and synchronized PowerPoint slide approach viewed as probable replacement.

• High quality Video and Audio • Multiple formats of Video • Mixture of pre-recorded and live video to enable remote site Q/A session • No new equipment at remote sites • Pre-scheduled start and stop times • Delivery to a large number of paying sites • Security

• Simultaneous Multicast and Unicast from our server over both Internet 2 and Internet • Microsoft’s Producer enabled recording and placing video/text material on a timeline. • Internet Explorer and Windowsmedia Player free downloads for remote sites • Windowsmedia Server capable of all desired features

Network configuration
• Both UAH and AREN Networks needed some upgrading to accommodate Multicast • Current streaming video server with MS Windowsmedia Sever software OK • Extensive testing of Multicast/Unicast to remote sites performed

Tutorial Delivery
• Lobby site had countdown clock and test video for last pre-check • Remote sites joined either a multicast or unicast “Lobby” site 15 Min. prior to start. • Start to finish of tutorial (~2.5 Hrs), including Live q/A session, remote sites were on “autopilot” and required no attention, as on TV.

Demonstration Tutorials
• National Children’s Advocacy Center Tutorial #2 (October 24, 2002). • Joint Class with French Engineering School ESTACA (February 2003)

A Few Technical Issues with Producer™ Multicast Deployment

• • • •

Multicast Group address space Software Version/Compatibility Issues Campus Networking Challenges Inter-domain Multicast Magic

Multicast Address Space
• Microsoft Producer™ uses randomly assigned Multicast group addresses • During initial testing, Microsoft defaults were used

• We began to worry that Producer™ was not reserving these addresses with any central authority
• The addresses could be overlapping with other applications (such as the legacy Mbone tools and Cisco IPTV) that can use SDR to reserve group addresses • Although this overlap may not cause application problems, it could result in unwanted traffic.

GLOP Addressing
• RFC3180 “GLOP Addressing in 233/8” • Current best practice is to use multicast address space that is derived from your AS number • Provides a single /24 of multicast address space per AS • UAH manages their GLOP addressing using their existing Unicast address inventory tool • Dynamic assignments can be made via an extension to DHCP called “MADCAP” [RFC2730] in the future

UAH’s GLOP Space
UAH Autonomous System Number: 10364
10364d = 00101000 01111100b

00101000b = 40d 01111100b = 124d AS 10364 

Troubleshooting IP Multicast Functionality of Microsoft Producer™

• Problems Encountered
– Client Software Version Issues – Campus Multicast Complications – Wide Area Inter-domain Multicast Problems

Client Software Issues
• Producer™ relies on Internet Explorer (IE) and Windows Media • Only foolproof configuration: Clients running XPpro operating system with updated Windows Media and IE • Good but spotty results with Win2K and Win98SE machines with updated Windows Media and IE • Use of XP was encouraged in testing since its used removed at least one possible problem from our troubleshooting list

Campus Multicast Complications
• UAH campus infrastructure upgrade (ATM to GigE) coincided with our multicast testing
– Initially had to disable mls for multicast on campus 6509 Layer3 switch/router.

• Testers outside Alabama often were unaware if IP Multicast was enabled on their local networks • Initial troubleshooting tool was Cisco IPTV
– attempting to view NASA clips from OR

• Best tool found: Internet2 Detective

Internet2 Detective
• • Test connection to Abilene • Test if subnet is Multicast Capable • Don’t need to call campus IT folks

Wide Area Inter-domain Multicast Troubleshooting • IP Multicast on Abilene currently relies on a combination of three protocols

• Problems were encountered when BGP used non-multicast capable links for traffic between UAH and AREN NOC
– Solved by judicious use of BGP filtering

• The BGP issue was a direct result of topology of network in Alabama

Alabama Logical Network Topology (GCG and AREN)
AREN-Hsv Router UAH/GCG Router


SoX Router UA/GCG Router

AREN-Bham Router

UAB/GCG Router

Inter-domain Multicast Troubleshooting Tools
• The most useful tool for troubleshooting: Router show commands
– We had direct access to AREN, UAH, and GCG routers.

• Abilene routers accessed trough the “Abilene Core Node Router Proxy”

Most Common Troubleshooting Commands for Cisco Routers
Router# show ip mroute
Router# show ip msdp peer

provides a look at the Multicast routing table
shows peer state, traffic, and filters

Router# show ip msdp sa-cache

shows the “service advertisement” cache and allows you to confirm msdp is correctly advertising sources. Confirms multicast routes are active (and tons of other stuff) Confirm PIM domain config is joining correctly

Router# show ip bgp neighbor Router# debug ip pim

Summary and Conclusions
• High quality Education and Training can be delivered to Internet 2 (and extensions) connected Schools in both live and asynchronous formats via Unicast/Multicast • Campus LAN Traffic inhibits Multicast video • Time zone differences encourage asynchronous Unicast delivery

Summary & Conclusions 2
• Many Universities who tested our NCAC Tutorials, could receive the Multicast material, but most elected the Unicast option. • “Homeland Defense” communication needs may advance Multicast capabilities. • For more info on UAH efforts, our “Case Study” is available from Microsoft’s website

Closing Credits
• • • • • • • UAH Computer & Network Services AREN NCAC Microsoft Producer and Windowsmedia Teams Dr. Robert Frederick (IPT Classes) Dr. Bill Kearns- Dir. USF-DMHC (pilot testing) Mr. James A Williamson Jr.- UAH Graduate Asst.

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