-- Note that the OSPF Sequence Number is a 32 bit signed
-- integer. It starts with the value '80000001'h,
-- or -'7FFFFFFF'h, and increments until '7FFFFFFF'h
-- Thus, a typical sequence number will be very negative.
'The sequence number field is a signed 32-bit integer.
It is used to detect old and duplicate link state
advertisements. The space of sequence numbers is
linearly ordered. The larger the sequence number the
more recent the advertisement.'
REFERENCE
'OSPF Version 2, Section 12.1.6 LS sequence number'