type of network described the network either shares the buffering with the source exchanging ownership of the buffer or the buffering is maintained by the source in either case the buffering must accommodate the amount of network data that can be in flight before an error is detected and a retry of the transmission is attempted fig2 shows a typical buffer 201 data from pointer a 202 in the buffer to pointer b 203 in the buffer is transmitted before the network determines that the data at pointer 202 in the buffer must be retransmitted two pointers must be maintained the 1 st defines the location of the last transmitted data that has not been confirmed as delivered the 2 nd defines the location of the next data to be transmitted in the absence of an error notification when an error notification occurs the value of the 2 nd pointer is set to the value of the 1 st pointer this is problematic for systems that where 1 the amount of data storage required at the source must be minimized 2 data creation rates approach or reach parity with network transmission rates or 3 source buffering is implemented as a fifo for simplicity reasons in the first case the amount of storage required for network data in flight may be substantial depending on network characteristics driving up the size of the buffer needed in the second case a retry.