When

Starting Time: March 23, 2009 at 1:00 PM, US/Eastern

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Agenda

Attendees

Notes

Use Cases

Evangelos has updated the topology sharing case. Andy is in progress for the service location use case. Martin would like to get these in by next week so there is editing time before SMM. Will try to pull out common items as necessary. Action is for everyone to finish/edit in the next 2 weeks.

Face To Face Meeting

We will meet at the Internet2 Spring Member Meeting. Due to lack of response we will not be able to provide a phone for dial in. We have 2 meetings between the member meeting to finish some of the use case work.

IP Summarization

Marcos from UDel talked about some of his ongoing work on improving the IP Summarization algorithms used in the perfSONAR gLS. Background is here. A quick summary of the current system and why it is necessary:

  1. Each hLS will receive service registrations from perfSONAR services
  2. Each registration contains items such as domain names, IP addresses, and keywords.
  3. The IP Summarization process attempts to find CIDR representations of the registered data so each hLS can advertise as being authoritative over some given range.
    1. Example: UDel has a class B address space (128.4.0.0/16). The DAMSL lab at UDel has a much smaller space (128.4.160.0/24). perfSONAR services will register items they control for each into an hLS and the hLS should be sure not to over advertise (say it has 128.0.0.0/8 for instance) or under advertise (claim it has 128.4.160.128/30 in another instance).
  4. hLS summaries are shared with gLS instances to facilitate discovery

Marcos is currently comparing the original algorithm developed by Jason with an Algorithm developed by martin along with a new attempt he has devised. The algorithm uses elements of Patricia Trie and min cut theory to find the best summarizations.

Future plans including taking into account tuning parameters such as making a summary tighter or looser depending on the needs of the service and improving the query interface (e.g. no more cold searching the database - use a radix tree or similar).

Martin adds some thoughts on the process including the need to support (or not) overlapping summaries for different hLS/Service ranges. Also talks about the point of view problem for searches originating in far away locations. Ex:

This distinction will allow a smaller margin of error.

Evangelos asks some questions since he was not too familiar with the goal. Mentions trying to make these summarizations based on AS information instead. Martin responds that using AS alone would not be good, but we can consider this suggestion as we evaluate the algorithm(s). Evangelos also talks about an OSCARS layer 3 service that would need to do something similar based on edge points.

Future Directions

Discussion trailed into the need for Authentication Support for Summarization and Discovery activities. Martin mentioned some parallel work on signed SOAP messages for perfSONAR clients and the Lookup Service. These activities will be closely related to summarization (e.g. summarize wide for the un-authenticated or tighter for those you trust - also may not want to share anything for the un-authenticated). Martin mentions this as a thorny issue with Topology sharing in DCN.

Evangelos mentions that he and others would feel better if future iterations did consider the AA aspects very carefully as many technologies that use the IS frameworks will rely on AA internally.

Conclusions

Call in 2 weeks to discuss use case progress. Marcos will update on Summarization again. Looking for other topics ahead of the F2F meeting.

ACTIONS: