Detection of failures in virtualized radio access networks
Data traffic is communicated between a radio unit (RU) of a cellular network and a virtualized radio access network (vRAN) instance of a vRAN. In response to determining that the vRAN instance has failed to communicate a downlink fronthaul packet to the RU within a threshold timeout interval, a failure notification is sent to a PHY layer failure response function. The failure to communicate the downlink fronthaul packet to the RU within the threshold timeout interval is indicative of a failure of the vRAN instance.
1. A method for detecting a failure in a virtualized radio access network (vRAN), comprising:
communicating, at the vRAN, data traffic between a radio unit (RU) of a cellular network and a vRAN instance of the vRAN, the vRAN instance configured to perform PHY layer processing and L2 processing of the data traffic, wherein the PHY layer is Layer 1 of the Open Systems Interconnection (OSI) model and the L2 is Layer 2 of the OSI model;
determining that the vRAN instance has failed to communicate a downlink fronthaul packet to the RU within a threshold timeout interval, wherein the threshold timeout interval is indicative of a maximum transmission time interval (TTI) between successive downlink fronthaul packets; and
in response to determining that the vRAN instance has failed to communicate the downlink fronthaul packet to the RU within the threshold timeout interval, sending a failure notification to a PHY layer failure response function, wherein a healthy vRAN instance communicates a downlink fronthaul packet to the RU within each TTI and a failure to communicate the downlink fronthaul packet to the RU within the threshold timeout interval is indicative of a failure of the vRAN instance.
2. The method of claim 1 , wherein the vRAN instance executes on a first server of the vRAN, the method further comprising:
in response to receiving the failure notification, initiating, by the PHY layer failure response function, a migration of the PHY layer processing to a second server of the vRAN.
3. The method of claim 2 , wherein the initiating comprises sending a command via a functional application platform interface (FAPI), wherein the FAPI is a standard interface between the PHY layer and the L2 layer.
4. The method of claim 2 , wherein the PHY layer processing comprises a PHY context including a memory context and computation context, and wherein the migration of the PHY layer processing comprises moving baseband processing of the RU from a PHY context on the first server to a PHY context on the second server.
5. The method of claim 4 , wherein the PHY context is instantiated on the second server as a backup PHY context for the RU.
6. The method of claim 1 , wherein the communicating, determining, and sending are performed by a programmable switch of the vRAN.
7. The method of claim 6 , wherein the determining is performed in a data plane of the programmable switch.
8. The method of claim 1 , wherein the determining and sending are performed within a same PHY processing slot of the vRAN instance.
9. A programmable switch configured to perform operations comprising:
communicating data traffic between a radio unit (RU) of a cellular network and a vRAN instance configured to perform PHY layer processing and L2 processing of the data traffic, wherein the PHY layer is Layer 1 of the Open Systems Interconnection (OSI) model and the L2 is Layer 2 of the OSI model;
determining that the vRAN instance has failed to communicate a downlink fronthaul packet to the RU within a threshold timeout interval, wherein the threshold timeout interval is indicative of a maximum transmission time interval (TTI) between successive downlink fronthaul packets; and
in response to determining that the vRAN instance has failed to communicate the downlink fronthaul packet to the RU within the threshold timeout interval, sending a failure notification to a PHY layer failure response function, wherein a healthy vRAN instance communicates a downlink fronthaul packet to the RU within each TTI and a failure to communicate the downlink fronthaul packet to the RU within the threshold timeout interval is indicative of a failure of the vRAN instance.
10. The programmable switch of claim 9 , wherein the threshold timeout interval is between 393 microseconds and 500 microseconds.
11. The programmable switch of claim 9 , wherein the determining is performed using a packet generator of the programmable switch, wherein the packet generator is configured to generate a timer packet at a predetermined fraction of the maximum TTI, wherein the programmable switch is further configured to perform operations comprising:
increment a value in a timeout register for each generated timer packet, and
determining that the vRAN instance has failed when the value in the timeout register reaches a predetermined value indicative of the threshold timeout interval.
12. The programmable switch of claim 11 , wherein sending the failure notification comprises reformatting the timer packet into a failure notification packet.
13. The programmable switch of claim 9 , wherein the determining is performed in a data plane of the programmable switch.
14. The programmable switch of claim 13 , wherein the determining and sending are performed within a same PHY processing slot of the vRAN instance.
15. A virtualized radio access network (vRAN) comprising:
a programmable switch; and
a server configured to execute a vRAN instance;
the programmable switch configured to:
communicate data traffic between a radio unit (RU) of a cellular network and the vRAN instance, the vRAN instance configured to perform PHY layer processing and L2 processing of the data traffic, wherein the PHY layer is Layer 1 of the Open Systems Interconnection (OSI) model and the L2 is Layer 2 of the OSI model;
determining that the vRAN instance has failed to communicate a downlink fronthaul packet to the RU within a threshold timeout interval, wherein the threshold timeout interval is indicative of a maximum transmission time interval (TTI) between successive downlink fronthaul packets; and
in response to determining that the vRAN instance has failed to communicate the downlink fronthaul packet to the RU within the threshold timeout interval, sending a failure notification to a PHY layer failure response function, wherein a healthy vRAN instance communicates a downlink fronthaul packet to the RU within each TTI and a failure to communicate the downlink fronthaul packet to the RU within the threshold timeout interval is indicative of a failure of the vRAN instance.
16. The vRAN of claim 15 , wherein the server is a first server of the vRAN and the programmable switch is configured to:
in response to receiving the failure notification, initiating, by the PHY layer failure response function, a migration of the PHY layer processing to a second server of the vRAN.
17. The vRAN of claim 16 , wherein the initiating comprises sending a command via a functional application platform interface (FAPI), wherein the FAPI is a standard interface between the PHY layer and the L2 layer.
18. The vRAN of claim 16 , wherein the PHY layer processing comprises a PHY context including a memory context and computation context, and wherein the migration of the PHY layer processing comprises moving baseband processing of the RU from a PHY context on the first server to a PHY context on the second server.
19. The vRAN of claim 18 , wherein the PHY context is instantiated on the second server as a backup PHY context for the RU.
20. The vRAN of claim 15 , wherein the threshold timeout interval is between 393 microseconds and 500 microseconds.