ospf флудит lsa каждый час
Under normal circumstances, updates to an LSP -- including purging,
if appropriate -- are the responsibility of the originator of the
LSP. There is a maximum time between generations of a given LSP.
Once this time has expired, it is the responsibility of the
originator to refresh the LSP (i.e., issue a new version with a
higher sequence number) even if the contents of the LSP have not
changed.