What is the transmit ring and how does it work?
The transmit ring is a control structure associated with the outbound port adapter. Each entry on the transmit ring is associated with one particle in the private interface pool. If a packet needs four private interface particles, it also uses four ring entries. The transmit ring is located on the NPE or NSE and points to packet content elsewhere in I/O memory that is awaiting transmission. The packet content is stored in particles of the inbound private interface pool. The transmit ring operates on a first-in first-out (FIFO) basis. When a packet is ready to be serviced by the transmit ring, a DMA transfer moves the packet contents from the private interface pool to the transmit buffer on the port adapter for SAR processing. Once the packet content has been transferred to the hardware buffer on the ATM port adapter, the ring entries are freed. Note If there is only a single transmit ring entry available, but the packet is larger and requires additional particles and therefore ring ent
