Host-daughtercard configuration with double data rate bus

Abstract

A double data rate bus system includes a host-network interface card configuration wherein the host is configured to recognize the network interface card to establish a double data rate bus between the host and the network interface card. The host is configured to generate a plurality of generic data frame queues. Each of the generic data frame queues is configured to receive and to transmit generic data frames via the double data rate bus. The network interface card is configured to transmit a plurality of dynamic memory access read requests to the host via the double data rate bus. The host is configured to allow each of the plurality of dynamic memory access read requests to remain pending prior to responding to anyone of the plurality of dynamic memory access read requests.

1 . An apparatus comprising:
 a network interface card configured to:
 generate a plurality of direct memory access (DMA) read requests; 
 transmit at least two of the plurality of DMA read requests over a bus to a host without reception of a DMA read response to at least one of the plurality of DMA read requests from the host. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the network interface card is configured to transmit the at least two of the plurality of DMA read requests over a plurality of transmissions. 
     
     
         3 . The apparatus of  claim 1 , wherein the network interface card is configured to transmit up to a maximum number of DMA read requests that are allowed to be pending with the host without reception of a DMA read response from the host. 
     
     
         4 . The apparatus of  claim 3 , wherein the maximum number of DMA read requests that are allowed to be pending with the host comprises eight DMA read requests. 
     
     
         5 . The apparatus of  claim 1 , wherein the network interface card is further configured to transmit DMA write frames that are interleaved with the plurality of DMA read requests. 
     
     
         6 . A system comprising:
 a host configured to:
 receive a plurality of direct memory access (DMA) read requests over a bus from a network interface card; 
 generate a DMA read response to at least one of the plurality of DMA read requests after receipt of at least two of the plurality of DMA read requests. 
   
     
     
         7 . The system of  claim 6 , wherein the host is configured to receive the at least two of the plurality of DMA read requests over a plurality of transmissions. 
     
     
         8 . The system of  claim 6 , wherein the host is configured to receive a maximum number of DMA read requests that are allowed to be pending with the host prior to generation of a DMA read response to at least one of the plurality of DMA read requests. 
     
     
         9 . The system of  claim 8 , wherein the maximum number of DMA read requests that are allowed to be pending with the host prior to generation a DMA read response comprises eight DMA read requests. 
     
     
         10 . The system of  claim 6 , wherein the host is configured to transmit a plurality of DMA read responses to the plurality of DMA read requests in an order corresponding to an order that the host received the plurality of DMA read requests. 
     
     
         11 . The system of  claim 6 , further comprising the network interface card in communication with the host through the bus, wherein the network interface card is configured to:
 generate the plurality of DMA read requests; and   transmit at least two of the plurality of DMA read requests over the bus to the host without reception of a DMA read response from the host.   
     
     
         12 . The system of  claim 11 , wherein the network interface card is further configured to transmit the plurality of DMA read requests interleaved with DMA write frames. 
     
     
         13 . A method comprising:
 generating, with a network interface card, a plurality of direct memory access (DMA) read requests; and   transmitting, with the network interface card, at least two of the plurality of DMA read requests over a bus to a host without receiving a DMA read response from the host.   
     
     
         14 . The method of  claim 13 , wherein transmitting, with the network interface card, at least two of the plurality of DMA read requests comprises:
 transmitting, with the network interface card, at least two of the plurality of DMA read requests in a plurality of transmissions.   
     
     
         15 . The method of  claim 13 , wherein transmitting, with the network interface card, at least two of the plurality of DMA read requests comprises transmitting, with the network interface card, up to a maximum number of DMA read requests that are allowed to be pending with the host. 
     
     
         16 . The method of  claim 15 , wherein the maximum number of DMA read requests that are allowed to be pending with the host comprises eight DMA read requests. 
     
     
         17 . The method of  claim 13 , further comprising:
 interleaving, with the network interface card, a plurality of DMA write frames with the plurality of DMA read requests; and   transmitting, with the network interface card, the plurality of DMA write frames interleaved with the plurality of DMA read requests.   
     
     
         18 . The method of  claim 13 , further comprising:
 receiving, with the host, at least two of the plurality of DMA read requests over the bus from the network interface card; and   generating, with the host, a DMA read response to at least one of the plurality of the plurality of DMA read requests after receiving the at least two of the plurality of DMA read requests.   
     
     
         19 . The method of  claim 18 , wherein receiving, with the host, at least two of the plurality of DMA read requests over the bus from the network interface card comprises: receiving, with the host, a maximum number of DMA read requests that are allowed to be pending with the host; and
 wherein generating, with the host, a DMA read response to at least one of the plurality of DMA read requests comprises: generating, with the host, a plurality of DMA read responses to the plurality of DMA read requests after receiving the maximum number of DMA read requests.   
     
     
         20 . The method of  claim 19 , further comprising:
 transmitting, with the host, the plurality of DMA read responses in an order corresponding to an order in which the DMA read requests were transmitted.