Interface with multiple packet preemption based on start indicators of different types

An apparatus comprising:

• a first device configured for communication with a second device via an interface bus;
• the first device comprising interface circuitry configured to receive from the second device a start indicator of a first type and a start indicator of a second type, and to allow at least one data segment associated with the start indicator of the second type to preempt at least one data segment associated with the start indicator of the first type;
• the interface bus comprising multiple signal lines;
• wherein the data segments are part of a data signal received over at least a first signal line of the interface bus;
• and
• wherein the start indicators are part of a start of packet signal received over a second signal line of the interface bus separate from and in parallel with said data signal.

A communication system comprising:

• a link layer device;
• and
• a physical layer device;
• the link layer device and the physical layer device being coupled together via an interface bus;
• at least one of the link layer device and the physical layer device being configured to receive from the other a start indicator of a first type and a start indicator of a second type, and to allow at least one data segment associated with the start indicator of the second type to preempt at least one data segment associated with the start indicator of the first type;
• the interface bus comprising multiple signal lines;
• wherein the data segments are part of a data signal received over at least a first signal line of the interface bus;
• and
• wherein the start indicators are part of a start of packet signal received over a second signal line of the interface bus separate from and in parallel with said data signal.