Subversion Repositories srdydrdy_lib

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/doc/intro_ethernet.pdf

doc/intro_ethernet.pdf Property changes : Added: svn:mime-type ## -0,0 +1 ## +application/octet-stream \ No newline at end of property Index: doc/bridge_example.txt =================================================================== --- doc/bridge_example.txt (nonexistent) +++ doc/bridge_example.txt (revision 22) @@ -0,0 +1,43 @@ +---------------------------------- + Example Bridge / Switching Hub +---------------------------------- + +The bridge directory contains an example bridge built using +srdy-drdy components. It could more accurately be called +a switching hub, since it does not implement spanning tree +or QoS. + +The bridge is designed for simplicity rather than efficiency, +as the purpose is not to make a functioning product but to +demonstrate use of the library. + +The bridge design pushes the bulk of the logic into each +individual port, called a port_macro. The only global logic +is the FIB (Forwarding Information Block) that contains the +address lookup and learning logic, and a centralized ring +arbiter. + +The port_macros are connected to each other via a ring interface. +Only one packet can be transmitted on the ring at a time. +The system is designed so that it has more ring bandwidth than +the maximum amount of incoming traffic, so that the ring should +not be the bottleneck for system performance. + +The bridge is designed to be output-queued, so that all packets +are forwarded to their output port and the output port will +drop packets if there is insufficient transmit bandwidth. + +The bridge handles all transmission errors on the input port, +using the rx_fifo to drop packets which arrive with bad CRC. +The parser waits until the end of packet is received to determine +if the packet is good, and only sends the packet to the FIB +if CRC is OK. Otherwise the parser errors the packet so it +will be dropped in RX FIFO. + +Packets are transmitted and received using an 8-bit GMII interface. +In order to create a higher-bandwidth internal interface, data +is aggregated into 64-bit words to get 8x bandwidth. This gives +the internal ring roughly 2x the bandwidth of all receiving ports +combined. + + Index: env/run =================================================================== --- env/run (revision 21) +++ env/run (revision 22) @@ -6,7 +6,7 @@ which iverilog &> /dev/null if [ "$?" == "0" ]; then rm -f a.out - iverilog -f bridge.vf tests/$TESTNAME.v $* |& tee compile.log + iverilog -f bridge.vf tests/$TESTNAME.v $* | tee compile.log ./a.out -lxt | tee run.log else vcs -full64 +v2k -R -I -f bridge.vf tests/$TESTNAME.v $*