The VIF module functionality analysis and design

The VIF module is responsible for adding new interfaces to the router. Adding a new interface consists in creating a new vif entry and adding it to the interface table, then starting the network stack for the newly added interface.

When adding a new interface, the function vdl_create is used to connect the interface to the data-link. After connecting to the data-link, the interface starts the upper layer protocols (VRIP,VARP and VIP), thus by creating six FIFOs for inter-layer communications (each couple of FIFOs establising a full duplex communication ) after that the vrouter calls the XXX_startup functions where XXX is an upper layer protocol to start the network stack processes for the new interface.

The following picture summarize the actions taken by the vrouter when creating a new interface.

Figure 2.2: Interface creation process