Area ID (4 bytes)

Protocol: OSPF OSPF PCI

PDU Part: common header / used by all OSPF packet types

Field: area ID

Length: 4 bytes

Contents: OSPF area ID.

A 32 bit number identifying the area that this packet belongs to. All OSPF packets are associated with a single area. Most travel a single hop only. Packets travelling over a virtual link are labelled with the backbone area ID of 0.