| 摘要 |
Packets transmitted over a data bus 14 from an incoming I/O (input/output) port 10a to an outgoing I/O port 10b are also stored in a shadow buffer 46. When the buffer 42 of an output port is full, a detector 44 asserts a buffer overflow error signal informing the shadow buffer controller 48 that the packet should be retained in the shadow buffer for later retransmission to the output port. The buffer overflow detector asserts a buffer available signal when room becomes available in the output port buffer and the packet is then forwarded from the shadow buffer to the port. The shadow buffer acts as a centralized memory resource for temporary storage of data packets which would otherwise be lost during transmission due to a full buffer in the outgoing port. The shadow buffer may be either a first-in-first-out (FIFO) memory or a random access memory (RAM) which may be indexed by an I/O port number. |
