close Warning: Can't synchronize with repository "(default)" (/common/SVN/crkit does not appear to be a Subversion repository.). Look in the Trac log for more information.

Changes between Version 6 and Version 7 of crkit/Software/Firmware/Framework/R3_arch/ip


Ignore:
Timestamp:
Jun 16, 2010, 8:42:25 PM (14 years ago)
Author:
khanhle
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • crkit/Software/Firmware/Framework/R3_arch/ip

    v6 v7  
    11== IPv4 ==
    22
    3 __Figure 1 - IP Packet Structure__
     3__Figure 1 - IP Packet Structure (source : wikipedia)__
    44[[BR]]
    55[[Image(ip_pkt.bmp, 1300px)]]
    … …  
    88 * '''Version''' == 0x4
    99 * '''Header Length''' == 0x5 (five 32-bit words)
     10 * '''Differentiated Services''' == 0x00 (not used)
     11 * '''Total Length''' == datagram size e.g. header + data (bytes). Note, header = 20 bytes.
     12 * '''Identification''' == 0x0000 (not used)
     13 * '''Flags''' == b000 (not used). Note, three-bit field.
     14 * '''Fragment Offset''' == b0 & 0x000 (not used). Note, 13-bit long.
     15 * '''Time to Live''' == 0x01
     16 * '''Protocol''' == 0x06 (TCP), 0x11 (UDP). More information at http://en.wikipedia.org/wiki/List_of_IP_protocol_numbers.
     17 * '''Header Checksum''' == computed as : all 16-bit words are summed together using one's complement (with the checksum field set to zero). The sum is then one's complemented and this final value is inserted as the checksum field.   
     18 * '''Source Address''' == Source IP
     19 * '''Destination Address''' == Destination IP
     20 * CRKit IP == 192.168.0.1 (hardwired until we have DHCP running).
     21 * Host IP  == 192.168.0.0 (default, but programmable from Packet Processor RMAP).
     22 * Further IPv4 information at http://en.wikipedia.org/wiki/IPv4#Data.
    1023
    1124