Circuit Switching Example Configuration Probe Dat Circuit Acknowledgement a Significant latency overhead prior to data transfer a Other requests forced to wait for resources
Circuit Switching Example ❑ Significant latency overhead prior to data transfer ❑ Other requests forced to wait for resources Acknowledgement Configuration Probe Data Circuit 0 5 7
Store forward Switchine Intermediate nodes Destination node ource node Each node along a route waits until a packet is completely received (stored)and then the packet is forwarded to the next node a I wo resources are neede Packet-sized buffer in the switch Exclusive use of the outgoing channel
Store & Forward Switching 9 Source node Intermediate nodes Destination node ❑ Each node along a route waits until a packet is completely received (stored) and then the packet is forwarded to the next node ❑ Two resources are needed ▪ Packet-sized buffer in the switch ▪ Exclusive use of the outgoing channel
Store Forward Switching Example High per-hop latency a Larger buffering required 11
❑ High per-hop latency ❑ Larger buffering required Store & Forward Switching Example 11
Store Forward Switchine OHBBBTI 田BBBT JHBBBT HBBBT 0 10 ycle 口 Advantage While waiting to acquire resources no channels are being held idle Disadvantage Requires a large amount of buffer space at each node Very hi h latency
❑ Advantage ▪ While waiting to acquire resources, no channels are being held idle ❑ Disadvantage ▪ Requires a large amount of buffer space at each node ▪ Very high latency 12 Store & Forward Switching
Virtual Cut-through Switching a transmission on the next channel starts directly when the new header flit is received a Channel is released after tail flit 0 HBBB 2 BIBb 0 10 Cycle
Virtual Cut-through Switching 14 ❑ Transmission on the next channel starts directly when the new header flit is received ❑ Channel is released after tail flit