Software Modules

The following figure illustrates the Segment Routing application components, and the relationship among those components

The boxes with bold text represents Segment Routing application modules while rest of the components represent ONOS modules that segment routing application depends on.

SPRING-OPEN TTP

App & Driver

The following figure describes the architecture of the segment routing application.

• Segment Routing Manager - It computes the shortest ECMP path among all routers and populates all routing rules to IP and MPLS table of the switches. Also, it handles all packets to the application and forwards them to appropriate handlers according to the packet type.
• ARP handler - It handles ARP request and response packets. If the APR request is to the any managed routers, then it generates and sends out the ARP response to the corresponding hosts. 
• ICMP handler - It handlers ICMP request to the routers. It generates the ICMP response packet and sends out to the corresponding hosts.
• Generic IP handler - It handles any IP packet. If the destination of the IP packet is hosts within subnets of routers, then it set the forwarding rule to the router and sends out the packet to the corresponding hosts. If MAC address of the host is not known, then it sends out APR request to the subnet using ARP handler.
• Segment Routing Policy - It creates the policy and set the policy rule to ACL table of routers. If it is the tunnel policy, then it creates the tunnel for the policy. NOTE: Load balancing policy is not implemented yet.

Configuration Manager