Routing protocols use different traffic types to control how routing information are exchanged.
Unicast: traffic is exchanged between one sender and one receiver, communication between two points.
Multicast: traffic is exchanged between one sender and group of receivers. IPv4 reserved address space is 224.0.0.0 – 239.255.255.255. IPv6 reserved multicast addresses have the prefix FF00:/8
Broadcast: one receiver send traffic to all devices in the subnet. Local subnet address is 255.255.255.255. IPv6 does not have broadcast traffic type.
Anycast: traffic is exchanged between one sender and nearest receiver from a group.
Early routing protocols used only broadcast traffic, but modern use multicast addresses.
Example IPv4:
- 224.0.0.5 – Used by OSPFv2: All OSPF routers
- 224.0.0.6 – Used by OSPFv2: All Designated routers
- 224.0.0.9 – Used by RIPv2
- 224.0.0.10 – Used by EIGRP
Example IPv6:
- FF02::5 – Used by OSPFv3: All OSPF Routers
- FF02::6 – Used by OSPFv3: All Designated Routers
- FF02::9 – Used by RIPng
- FF02::A – Used by EIGRP for IPv6
