OSPF packet

[Arjun Dabol]

Hi

Can someone explain me in simple networking terms ...where does OSPF packet fits in a typical IP packet ?

and since 'OSPF LSA' carries prefix and other info..where does that fit in over all IP Packet concept ?

Is there any encapsulation happening here?

Thanks

[paul driver]

Hello

Within the ospf packet amongst other information the ospf header specifies the packet type and the LSA header specifies the lsa type.

This ospf packet is then encapsulated by ip and the protocol number within this ip header specifies what transport is to be used to carry data and for ospf this will be protocol 89

L2 header| ip header (protocol) | ospf header  | ospf lsa header  |  L2 trailer     

[omz]

OSPF runs over IP. Each OSPF packet (Hello, DBD, LSR, LSU, LSAck) has an OSPF header with the message type. There is no message type 'LSA', LSAs are sent in LSU and LSAck messages and LS type of requested LSAs in LS request packets.

[Joseph W. Doherty]

Probably Paul and omc79 have answered your questions, but another short reply . . .

"...where does OSPF packet fits in a typical IP packet ?"

It's its own defined IP protocol, just like other IP protocols such as TCP, UDP, ICMP, etc. See https://en.wikipedia.org/wiki/List_of_IP_protocol_numbers for a list of IP protocols (NB: you'll find OSPF is protocol number 89).

". . . since 'OSPF LSA' carries prefix and other info..where does that fit in over all IP Packet concept ?"

That's up to the protocol to define how the IP data portion of the packet is allocated.

"Is there any encapsulation happening here?"

Yes (for L2, L3 and OSPF).