MC9S12NE64 - Page 2

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Re: MC9S12NE64
The PC never decreases the speed of the TCP reception because it can
buffer and process each TCP packet fast enough that the remote peer
does not notice it. This is achieved by keeping the TCP window
unchanged. A key behavior in a fully compliant RFC TCP stack is that
while buffering all received packets, a host can use a single
acknowledgement for several received packets. This is not the case for
OpenTCP.
OpenTCP sends an ACK for every TCP packet it processes successfully in
a sequential manner. Although the reception of each packet on the NE64
is performed on an interrupt context (or "foreground" context), the
actual processing happens using simple polling in the main loop. This
increases the latency of the stack. If both buffers (A and B) on the
NE64 are not empty (for example one of them is being processed and the
other stores a retransmitted packet), new receive frames are dropped
silently until one of the buffers becomes available.
By design under these conditions it is impossible for the NE64 EMAC to
know how many and what packets were dropped. All dropped packets will
re-appear on the network as retransmissions sooner or later and this
will cause the extra retransmissions and late ACKs experienced by you
guys.


Re: MC9S12NE64
Hi, Can you tell me from where to download the Freescale version of th
OpenTCP.

Thanks



        
This message was sent using the comp.arch.embedded web interface o
www.EmbeddedRelated.com

Site Timeline