Comments about Multicast and Access Grid

1. My institution has not successfully deployed multicast.
2. in my experience, the multicast issues usually occurs in this order. 1 - Department LAN 2 - Campus / Organization LAN 3 - Campus/Org connection to I2 4 - I2 WAN.
3. When it works, it's great. Fortunately, for us it usually works.
4. MC issues are almost always local issues. Our host institution resists allowing widespread usage of multicast. We have 2 specific ports at our facility that the institutional networking support allows MC traffic to go to. This is almost always workable. When we have problems, it's typically a 1-way MC issue; we can get audio and video in, but can't trasmit both. These types of issues tend to disappear on their own, over the course of a day. We've not been very sucessful in identifying the actual problem when this behavior is observed. Fortunately, the bad behavior is infrequent and most of the venues that we visit are bridged for the occasion when MC fails.
5. Everyone who shows an interest in AccessGrid must be told in clear firm terms that multicast is a necessity and that using crutches like a unicast bridge should only be done as necessary to convince upper management of the value of AccessGrid.
6. it's gotten better but, we're a long way out from it being a simple task :(
7. I am able to multicast, however some of the sites that I connect to have a lot of problems
8. The AG's need (preference) for multicast is a great technology driver - in that network engineers are driven to make their networks operated properly. Unicast bridges are a convenient workaround, enabling network engineers to not do their job (of configuring their routers etc to accomodate multicast).
9. The media tools launch and run better when using multicast.
10. Normally works OK for us on AG2.3 - main issue is in the bridging other sites use, particularly between Insors nodes in the US & us in the UK.
11. Multicast is important for performance, primarily efficient use of bandwidth. Because of from what I see as its limited availability, unicast bridging is critical to the success of a collaboration tool such as AG.
12. Would be nice to have a clear document stating what ports to open up for firewall folks (uni and mono)
    
13. Multicast has been totally unreliable, with two years' experience. We rarely can have a conference without dropping connections at least once--which is very disruptive. We sometimes use bridged mode via inSORS.
14. Multicast is the source of about 99% of our problems. And since we don't have any control of the entire network, end to end quality of service is a best effort of the node ops.
15. Somewhere upstream outside of our state there is a few folks we can not send multicast to, but generally 95% of the time it is not a problem. I train my operators to always be prepared to work around a potential multicast problem, fortunately it's usually working and we advise sites who do have multicast issues how to connect to use utilizing unicast.
16. I am only able to use multicast to connect to a locally based venue-server. When connecting to an overseas venue-server, I am always forced to use a unicast connection.
17. I am a developer and I can use multicast for my test locally. However, none of the events transmitted in the US I have been able to receive in multicast. It seems to be broken somewhere along the way from the US to the UK...
18. Always works for me.
19. Sometimes when meeting with people who are using a bridge we seem to have trouble, meeting with other straightforward multicast sites is usually good.
20. The main problem is that Multicast is not set up by default at most institutions.
21. There was a problem with Multicast within XXXXX University's network, but this has now been fixed with a router upgrade. Since then Multicast has been functioning very well.
22. We have router problems here. We can receive multicast but cannot transmit outside our organisation
23. Although the university has multicast from outside to the border router, there is still no multicast on the LAN (Problems with the backbone switches). Its on their todo list, but is a low priority.
24. Ultimately people need to get multicast sorted. I'm amazed at how slow the adoption of multicast has been, especially at the normal ISP level, as potentially it could save a shedload of bandwidth.
25. We used to use multicast 95% of the time. Then a fault on a site router which affected the whole site was fixed, and since then multicast has suffered frequent (e.g. every 30 seconds) dropouts, so for the last 9 months we've had to use unicast and bridges. The router manufacturer hasn't been able to fix themulticast problem.
26. As known well, multicast reachability is not available to common PC users. Even now, only advanced research institutes can have multicast. Our organization fortunately could prepare multicast but it has not been working reliably. I feel, in 50% of important meetings, we have had a multicast-related problem.
27. Normally great, but problems are extremely hard to track down. Not network ops are weak on understanding MC and/or MC diagnostic tools.
28. Needs more monitoring/diagnostic tools
29. my I2 connection is not multicast enabled, so i must connect unicast.
30. I have gone to great efforts to have my laptops ip address added to the routed mcast address range and getting our site properly configured for mbgp. Not easy. For adding new or occational users to an AG session unicast will be invaluable and is something I intend to look into. I have also as yet not been able to use AG form home :(
31. Great solution to the problem... but it needs to be _much_ more consistent.
32. Am not clear on how to troubleshoot multicast
33. We use unicast only on networks that do not support multicast or where there is a multicast error.
34. Public bridges and a more unified 'home' venue would help proliferate AccessGrid technology.
35. no
36. Often the network converges to a multicast tree slowly, so it takes a while for my video and audio to start to be received by other nodes.
37. We also have running a Unicast to Multicast Bridge Server
38. Excellent
39. The network does need to be open and good communication with networking on site. We had a few problems getting them to understand what ports should be open, what is really a multicast problems, etc.
40. multicast is definitely nice and the way to go with multipoint conferencilng, to eliminate MCU type requirements. but the unicast option needs to be there since edu networks at least are in flux and sometimes mcast is not available; and some users don't have mcast but should be accommodated (the user/use is more important than the technology).
41. Occassional glitches with international multicast between Australia (home) and oversease (US/Canada)
42. multicast is a state of the grid which is needed for effective and efficient grid computing. The Accessgrid emerged in 99 as a tool to debug multicast for this effort. In it's current role as a video conferencing system, multicast is helpful but not mandatory. The underlying premise of the AccessGrid, however, is as an interface to enable grid computing.
43. Multicast on the WAN is ok, on our Lan is a problem.
44. all we can say that multicast is good to use for the accessgrid than unicast.
45. need debug tool
46. Using multicast is good, but I usually cannot find out how to enable multicast through Venue Client, the interface is not so user friendly.
47. It's rather new that we can use multicast. In the past we only could use unicast.
48. Makes sense as long as it works.
49. We've had some (very few) occasions when multicast wasn't working on one of the routers connecting us to our gigapop. Some times we've resorted to unicast with an endpoint that didn't have multicast. Other than these very few times, multicast has worked.
50. I have to use unicast because I am behind a firewall and on a commodity Internet connection that doesn't support multicast.