Understanding the packet life cycle

In the Learning about network conceptual models section, we explained that to optimize the communication between the exchange and trading systems, we will use copper or optical wire. This wire is connected to the NIC. This wire will transport the packets containing market data from the exchange and orders going to the exchange.

We first need to discuss which message we are passing on this wire. This section will use the FIX protocol we defined in this chapter. Let's consider the following example of a FIX message:

8=FIX.4.2|9=95|35=X|34=5|49=NYSE|52=20160617-23:12:05.551|56=TRADSYS|268=1|279=1|269=1|270=110|271=5|37=9|10=209|.

This FIX message will be the payload of the packet shown in Figure 5.18.

The packet has two main parts. The headers contain information for each layer of the OSI model and a payload containing the FIX message, as shown here:

Figure 5.18 – Packet headers

The Ethernet layer...