4.4.3.1. LSA Options

The Options field in LSAs should be coded as follows. The V6-bit should be set unless the router will not participate in transit IPv6 routing. The E-bit should be clear if and only if the attached area is an OSPF stub or OSPF NSSA area. The E-bit should always be set in AS scoped LSAs. The N-bit should be set if and only if the attached area is an OSPF NSSA area. The R-bit should be set unless the router will not participate in any transit routing. The DC-bit should be set if and only if the router can correctly process the DoNotAge bit when it appears in the LS age field of LSAs (see [DEMAND]). All unrecognized bits in the Options field should be cleared.

The V6-bit and R-bit are only examined in Router-LSAs during the SPF computation. In other LSA types containing options, they are set for informational purposes only.

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