OSPF Type 1: Hello
Network Mask (4 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : network mask
Length : 4 bytes
Contents : IP subnet mask.
Class A = 0xFF000000
Class B = 0xFFFF0000
Class C = 0xFFFFFF00
Options (2 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : Options
Length : 2 Bytes
Contents : OSPF option identifier.
Router Priority (2 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : router priority
Length : 2 bytes
Contents : router priority indicator.
The priority indicator is used to determin the (Backup) Designated Router.
Dead Interval (4 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : dead interval
Length : 4 bytes
Contents : maximum time to send OSPF packets.
If an OSPF router didn't send any OSPF packet during the dead intverval (value: seconds) it is assumed to be dead (stopped, out of order): number of seconds before declaring a silent router down.
Designated Router (4 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : designated router
Length : 4 bytes
Contents : IP address of the designated router.
The designated router from the point of view of an advertising router in a given network. The designated router is identified by its IP address. In case that no designated router exists, this field is set to zero.
Backup Designated Router (4 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : backup designated Router
Length : 4 bytes
Contents : IP address of the backup designated router.
The backup designated router from the point of view of an advertising router in a given network. The backup designated router is identified by its IP address. In case that no backup designated router exists, this field is set to zero.
Neighbor (4 bytes)
Protocol : OSPF OSPF PCI
OSPF Type: Type 1 / Hello
Field : neighbor
Length : 4 bytes
Contents : known OSPF routers in the given network.
This field contains the router IDs (IP addresses) of all routers that had sent OSPF hello packets within the last dead interval (DeadInt).