Understanding TCP/IP Model Internals and Interfaces

1508 Understanding TCP/IP Model Internals and Interfaces
Sending a Packet to IP
The MAC process receives a packet from the network, it decapsulates the IP packet from the MAC
packet and sends it to the ARP module. No ICIs are involved here. In the simple_mac process model
this is performed in the function simple_mac_packet_from_ntwk_handle (no need to
make any coding changes):
FIN (simple_mac_packet_from_ntwk_handle (mac_pkptr));
/* Decapsulate the IP datagram from the packet. */
op_pk_nfd_get (mac_pkptr, "data", &ip_pkptr);
/* Print a trace Message */
if (SMC_LTRACE_ACTIVE)
{
/* Get the source address from the packet */
op_pk_nfd_get (mac_pkptr, "source address",
&source_address);
sprintf (msg, "Source Address: %d", source_address);
op_prg_odb_print_major ("Received a Packet from the”
“Network", msg, OPC_NIL);
}
/* Send the packet to the higher layer. */
op_pk_send (ip_pkptr, SMC_OUT_STRM_INDEX_TO_ARP);
/* Destroy the MAC packet. */
op_pk_destroy (mac_pkptr);
FOUT;
Save and Compile the Process Model
1. Save and compile the process model.
2. If you are having problems in compilation, you may
a. Close the simple_mac process model.
b. Open the simple_mac_ref process model.
c. Save it as simple_mac.
d. Recompile.
CONFIDENTIAL – RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc.
© 2010 OPNET Technologies, Inc.
36