ATTENDEES:
Kukhee, Till, Steph, Ernest, Terri, Antonio, Debbie, Diane, Sheng
TOPIC:
We discussed three options for handling the private network message traffic between IOCs and EIOCs when we add the FCOM multicast network. I've attached (corrected) slides used in the discussion. The following is a list of the options
Option 1) Share the 2960 switch with private network and new multicast network. VME IOC to coldfire EIOC messages: change broadcast message to a multicast message. The software effort for this option is fully included in the current schedule. There may be additional cost in upgrading 2960s to 3750s.
This approach may have trouble meeting our latency requirements so Till and Antonio need further off-line discussion on how one might set up switches to block IOC<-->EIOC traffic from travelling up to CORE.
Option 2) Share the 2960 switch with private network and new multicast network. VME IOC to coldfire EIOC messages: Change broadcast message to serial unicast messages. This includes additional effort to code, configure and manage essentially hard-coded IP and MAC addressses for the RF, BPM and BLEN IOCs and EIOCs.
Option 3) Add a third NIC to all subsystems with EIOCS, add second NIC to magnets. Requires additional cost to add NICs for all IOCs involved in feedback. Requires additional effort to research/find the right card, modify RTEMS ip/udp stack and write a driver for the new card.
See below a table of the Pros and Cons for these three approaches - which will be complete when all action items from this meeting are complete.
ACTION ITEMS:
- Diane and Sheng - latency calculations for option 1)
- Terri - cost estimate for upgrading 2960s (is it already included in the Fast Feedback costs?)
- Till & Antonio - further discussion on switch configurations for option 1)
- Sheng,Kukhee,Till,Ernest - coding effort required in option 2) rough estimate (in weeks) for BPMs, BLEN, RF --and list configuration concerns
- Till - software effort required for option 3)
- Ernest/Terri - cost estimate for option 3)
Tradeoff |
Option 1 |
Option 2 |
Option 3 |
|---|---|---|---|
Description |
Shared Switch. Multicast messaging replaces broadcast |
Shared Switch. Unicast messaging replaces broadcast |
Additional NIC |
Technical Risks |
* BPM IOCs send broadcast at 360Hz |
?any technical reason this won't work? |
* changes to ip/udp stack can adversely effect the EIOC performance, since the EIOC uses the same code base |
Maintenance Risks |
* blocking on switches is difficult to configure/maintain - so much so that SCCS may ask Controls to take over network maintenance |
* every IOC / EIOC needs 'hardcoded' configuration that is difficult to maintain |
NIC may become obselete |
Additional Software Effort |
* NA - already in schedule |
* develop configuration scheme |
* research / test card |
Additional Hardware Cost |
* upgrade 2960s to 3750s |
NA |
a NIC for each Feedback IOC |