Identifying Where the Traffic Can Leave
Traffic flows
- Each flow has a dest IP address (e.g., 12.34.156.5)
- Each address belongs to a prefix (e.g., 12.34.156.0/24)
Forwarding tables
- Each router has a table to forward a packet to ìnext hopî
- Forwarding table maps a prefix to a ìnext hopî link
Process
- Dump the forwarding table from each router
- Identify entries where the ìnext hopî is an egress link
- Identify set of egress links associated with each prefix
- Associate flowís dest address with the set of egress links