ECE1373 Notes
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[edit] General issues
- Routing tables in large networks gets quite large. The current Internet routing table is approaching 300k entries[1]. Memory required for routing tables may limit the number of routers that can be put on one FPGA.
- Memory for packet buffers may get big. EP2C35 has ~59KB on-chip memory total, probably not enough for typical buffers for even one node.
- Difficulties in Simulating the Internet.
- Time-Warped Network Emulation.
[edit] To-Do List
- Add support for dropping packets in simulator
- Rename "ready_delta" to be "early_limit". Introduce concept of "late_limit". "early_limit" is expensive to implement, so set to 1. "late_limit" seems cheap on hardware, so pipeline the interconnect and set "late_limit" to ~4-6. Will try in Thing3? "late_limit" should give similar performance benefits as "early_limit", but be easier to build.
- Find a good interconnect topology
- Find queue timestamp algorithm that does not use division.
- Replace the non-deterministic Perl rand() used in parse_alt.pl
- Fixed using srand() to seed the rand())
[edit] Limitations of current implementation
- Address format (bus ID -- part ID -- node ID) means that we're wasting the address space if a partition has fewer than 32 nodes
