Routing Logic

List of Tables

Table Name	Match	Action
BasicTable	Incoming Port	Send to destination Port p
PSR routing	PSR Beam number	Send to destination Port p
Multicast SPEAD	Triple <freq, subarray, beam>	Send to multicast group
Unicast SPEAD	Triple <freq, subarray, beam>	Send to destination Port p
Change MAC address	Dst IP Address	Change MAC dst addr
IP routing	Dst IP Address	Send to destination Port p
PTP routing from Clock	Incoming Port	Send to multicast group 1
PTP routing to Clock	Incoming Port	Send to destination Port p
ARP traffic	Target IP	3 actions: SDP queries, answers, and SPS

General Logic

On arrival switch attempt to extract all relevant headers. Then try to match each table in sequence:

1. Try to match Basic Table

2. If protocol P present then:

   • If P = SPS Spead, match spead multicast then unicast

   • If P = PSR, match PSR

   • If P = UDP, match MAC changing, then IP forwarding

   • If P = PTP, match “PTP routing from Clock” then “PTP routing to Clock”

   • If P = ARP, match ARP table

   • If P = IPv4, perform TTL = TTL-1

3. Try to apply Multicast Table

Logic is sequential meaning that the last rule that will be matched always win. i.e. If a packet matches basic rule and also matches the SPEAD unicast rule then SPEAD unicast wins.

Conflict might occur if:

• Basic rule and any other rules are matches

• Protocol rules and IP forwarding rules are matches

• Any rules in step 1 and 2 getting overruled by Multicast rule in step 3

Flowchart

flowchart TB Arrive[Packet Arrives] --> Extract(Extract Headers) Extract --> Multi{Multicast Table?} Multi -- Yes --> ApplyMulti(Apply Multicast rule) Multi -- No --> IP{IPv4?} IP -- Yes --> TTL(Decrement TTL) subgraph IP Based Protocols TTL --> IP_FORWARD{IP DEST Match} IP_FORWARD -- No --> PSR{PSR?} PSR -- No --> SPS_M{SPS SPEAD\nMulticast?} SPS_M -- No --> SPS_U{SPS SPEAD\nUnicast?} end IP -- No --> ARP{ARP?} subgraph "Non-IP Protocols" ARP -- No --> PTP{PTP?} end PTP -- No --> Basic ARP -- Yes --> ApplyARD(Apply ARP rule) PTP -- Yes --> ApplyPTP(Apply PTP rule) IP_FORWARD -- Yes --> ApplyIPForward(Apply IP Forward rule) PSR -- Yes --> ApplyPSR(Apply PSR rule) SPS_M -- Yes --> ApplySPSM(Apply SPS Multicast rule) SPS_U -- Yes --> ApplySPSU(Apply SPS Unicast rule) SPS_U -- No --> Basic{Basic Table?} Basic -- Yes --> ApplyBasicRule(Apply Basic rule) Basic -- No --> Discard