Emulating collisions in wired local area networks and related systems, methods, and devices

Abstract

Various embodiments relate to wired local area networks. A method may include detecting, at a node in a wired local area network, at least one event. A physical layer device of the network node is configured to implement a physical level collision avoidance (PLCA) sublayer. The at least one event may include at least one of an amount of data stored in a first-in-first-out (FIFO) buffer of the node being at least a threshold amount, and a received packet being a precision time protocol (PTP) packet incurring variable delay. The method may further include emulating a collision at the node in response to the at least one detected event.

We claim: 
     
         1 . An apparatus, comprising:
 a buffer for a network node, the buffer to receive a transmit packet; and   a control circuitry for the network node, the control circuitry to:
 detect at least one event including at least one of:
 an amount of data stored by the buffer being at least a threshold amount, or 
 the received transmit packet being a precision time protocol (PTP) packet incurring variable delay; and 
 
 emulate a collision at the network node by asserting a collision signal in response to the at least one detected event. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the control circuitry is to pad the PTP packet so as to include at least 64 bytes responsive to a detection that the received transmit packet is the PTP packet received outside of a transmit opportunity of the network node. 
     
     
         3 . The apparatus of  claim 1 , wherein the control circuitry is to pad the PTP packet to include a pattern to cause an error responsive to a detection that the received transmit packet is the PTP packet received outside of a transmit opportunity of the network node. 
     
     
         4 . The apparatus of  claim 3 , wherein the pattern includes 010101. 
     
     
         5 . The apparatus of  claim 1 , wherein the control circuitry is to add an error delimiter to the PTP packet responsive to a detection that the received transmit is the PTP packet received outside of a transmit opportunity of the network node. 
     
     
         6 . The apparatus of  claim 1 , wherein responsive to a detection that the received transmit packet is the PTP packet received outside of a transmit opportunity of the network node, the control circuitry is to:
 pad the PTP packet with a pattern such that the PTP packet includes at least 64 bytes of payload and the pattern causes an error; and   add an end-of-stream delimiter to the PTP packet.   
     
     
         7 . The apparatus of  claim 1 , wherein the control circuitry is to detect a fixed delay incurred by the PTP packet responsive to a transmit enable signal assertion within a transmit opportunity of the network node or responsive to a deassertion of a carrier sense signal after an emulated collision. 
     
     
         8 . An apparatus, comprising:
 a buffer for a network node, the buffer to store a transmit packet to be transmitted by the network node; and   a control circuitry for the network node, the control circuitry to:
 determine that an amount of data stored in the buffer is at least a threshold amount; and 
 emulate a collision by asserting a collision signal in response to the amount of data being at least the threshold amount. 
   
     
     
         9 . The apparatus of  claim 8 , wherein the threshold amount programmable to be a maximum of 49.5 bytes. 
     
     
         10 . The apparatus of  claim 8 , wherein the network node is part of a wired local area network including more than eight (8) network nodes. 
     
     
         11 . The apparatus of  claim 8 , wherein the control circuitry is to emulate the collision on a media independent interface (MII). 
     
     
         12 . An apparatus, comprising:
 a buffer for a network node, the buffer to store a transmit packet to be transmitted by the network node; and   a control circuitry for the network node, the control circuitry to:
 identify the stored transmit packet as a precision time protocol (PTP) packet; and 
 emulate a collision at the network node by asserting a collision signal to a media access control sublayer in response to the stored transmit packet being identified as the PTP packet and the PTP packet incurring variable delay. 
   
     
     
         13 . The apparatus of  claim 12 , wherein the control circuitry is to emulate a collision by asserting the collision signal to the media access control sublayer in response to an amount of data stored by the buffer exceeding a predetermined threshold level. 
     
     
         14 . The apparatus of  claim 12 , wherein the control circuitry is to at least one of:
 pad the PTP packet with a pattern such that the padded PTP packet includes at least 64 bytes and the pattern causes an error; or add an end-of-stream delimiter to the PTP packet.   
     
     
         15 . The apparatus of  claim 12 , wherein the control circuitry is to emulate the collision on a media independent interface (MII) or a reduced media independent interface (RMII). 
     
     
         16 . A system, comprising:
 a network node including a physical layer (PHY), the PHY to:
 detect at least one event including at least one of an amount of data stored in a buffer of the network node being at least a threshold amount and a received packet being a precision time protocol (PTP) packet incurring variable delay; and 
 emulate a collision at the network node in response to the at least one detected event. 
   
     
     
         17 . The system of  claim 16 , the PHY further configured to:
 pad the PTP packet with a pattern such that the padded PTP packet includes at least 64 bytes and the pattern causes a cyclic redundancy check (CRC) error; and   add an end-of-stream delimiter to the PTP packet.   
     
     
         18 . The system of  claim 16 , wherein the received packet is received from a media access control sublayer of the node. 
     
     
         19 . The system of  claim 16 , wherein the threshold amount is programmable to be less than or equal to one of 49.5 bytes or 64 bytes. 
     
     
         20 . An apparatus, comprising:
 a number of network nodes for a vehicle, at least one network node of the number of network nodes to:
 detect at least one event, the at least one event including at least one of: an amount of data stored in a buffer of the at least one network node being at least a threshold amount; and a transmit packet received at the network node from a link layer of the network node being a precision time protocol (PTP) packet and incurring variable delay; and 
 emulate a collision at the at least one network node in response to the at least one detected event.