Importance of LS length in DB exchange start packet (OSPF protocol)?

Applications IP Networking
1

Is there any importance of LS length in DB exchange packet of OSPF protocol as its should be always be 20 bytes. Is this length to be ignored

2

RFC 5243 doesn't mention anything about your question. If when referring to LS you mean "Link State" please make this clearer. If yes, the answer is Yes, 20 bytes is the size of OSPF header.Those are first 20 bytes of the LSA.

3

yes LS means Link state. yes RFC does not mention it...thats why I asked....
However I figured it out the answer, LS header in database description exchange start packet in itself of the preview of the LS update packet that will be sent after this. So this LS header is just exact copy of the the LS header in a update packet(this includes length also checksum: this means the length and checksum in LS header of DB description start packet does not correspond to itself but of LS update packet sent later).
However I also think this checksum and length is ignored and not used in the routing softwares.