P4 based implementation of BIER and BIER-FRR

Repository structure

Local-Controller: Contains the local control plane

src: Contains the p4 based implementation of BIER and BIER-FRR

Pipeline

Incoming packets are processed - dependending on their ethernet type - by different control blocks (CB), e.g. IP or BIER.

• IP-CB: src/controls/IP.p4
• BIER-CB: src/controls/BIER.p4
• Ethernet-CB: src/controls/Mac.p4

FRR-Implementation

FRR is implemented based on port monitoring. Tofino generates a special packet when a port goes down (src/controls/Port_Down.p4). This information is saved in a register. Each port corresponds to it's own register index.

Register<bit<1>, PortId_t>(2069, 0) port_status_reg;

After the CBs are processed, e.g. IP oder BIER, the egress_port is specified. Afterwards, the Port-CB (src/controls/Port.p4) checks if the port is up (see src/ingress.p4).

If the port is not up, the corresponding FRR-CBs are processed.

• IP-FRR-CB: src/controls/IP_FRR.p4
• BIER-FRR-CB: src/controls/BIER_FRR.p4