What is OSPF area ID?
An OSPF area is a logical grouping of routers sharing the same 32-bit Area ID. The Area ID can be expressed in dotted decimal notation similar to an IP address, such as 192.168. 17.33. The Area ID can also be expressed as a decimal equivalent, so Area 261 is the same as Area 0.0.
How big should an OSPF area be?
Generally, an area should have no more than 50 routers. Areas that suffer with unstable links should be smaller. Number of areas supported by any one router: A router must run the link-state algorithm for each link-state change that occurs for every area in which the router resides.
How is OSPF router ID determined?
Each OSPF router selects a router ID (RID) that has to be unique on your network. OSPF stores the topology of the network in its LSDB (Link State Database) and each router is identified with its unique router ID , if you have duplicate router IDs then you will run into reachability issues.
What does OSPF packet format contain?
OSPF packet header Type—OSPF packet type from 1 to 5, corresponding to hello, DD, LSR, LSU, and LSAck, respectively. Packet length—Total length of the OSPF packet in bytes, including the header. Router ID—ID of the advertising router. Area ID—ID of the area where the advertising router resides.
What is a area ID?
An area ID identifies the specific group, or area, to which a network or interface belongs. Therefore, OSPF uses area IDs to organize a topology and to determine the neighbor routers to which it should send the packets that build the link-state database (LSDB).
How do I change the MTU size in OSPF?
By default the MTU configuration option is available under config router >> config ospf-interface hierarchy. FortiOS supports default MTU value of 1500 on all FortiOS versions. The default value of MTU size under OSPF interface is seen as ‘0’.
What is process ID and router ID in OSPF?
Process IDs are locally significant and are used to differentiate multiple instances of OSPF on the same router, as configured with. Router IDs identify each router and they must be unique. They are used by routers to determine each of them will be the Designated Router and Backup Designated Router.
What is the size of OSPF header?
24 bytes
The length of an OSPF packet header is 24 bytes.
What is MTU size for OSPF?
1500
FortiOS supports default MTU value of 1500 on all FortiOS versions. The default value of MTU size under OSPF interface is seen as ‘0’. This implies that ospf-interface does not change the default MTU value of 1500.
What is an OSPF area ID?
IT Certification and Training Blog. An area ID identifies the specific group, or area, to which a network or interface belongs. Therefore, OSPF uses area IDs to organize a topology and to determine the neighbor routers to which it should send the packets that build the link-state database (LSDB).
What is the size of OSPF packet?
Each OSPF packet belongs to 1 area. A 4 byte IP Address format is used to denote it. For the backbone area packet, the area ID is 0.0.0.0 For other areas like area 1 it contains the value as 0.0.0.1 and so on.
What does OpenOSPF do when the area ID is 0?
OSPF sees both formats as the same value and will establish an adjacency between neighboring routers even if the area ID is 0 on one end and 0.0.0.0 on the other.
What is the protocol number for OSPF?
Rather than, the OSPF forms the IP datagram directly, packaging t using the protocol number of 89 for an IP protocol field. In the OSPF, there are 5 different types of packets. The format of the common OSPF header is shown below.