Cisco Systems OL-4580-01 manual Field, Description, ADV Router, 3-35

Chapter 3 Configuring Open Shortest Path First (OSPF)

Showing OSPF Information

Table 3-6 Field Descriptions for the show ospf lsdb Command (continued)

Field	Description
ADV Router	This field specifies the OSPF Router ID of the LSA
	originator, as follows:
	• ASB-Summary LSAs, the originators are the ABRs
	• AS-external LSAs, the originators are ASBRs
	• Network LSAs, the originators are network-designated
	routers
	• Router LSAs, this field is identical to the Link State ID
	field
	• Summary LSAs, the originators are the ABRs
Age	The age of the LSA, in seconds. The age is set to 0 when
	the LSA is originated.
Sequence	A signed 32-bit integer to detect old and duplicate LSAs.
	The space of sequence numbers is linearly ordered. The
	larger the sequence number (when compared as signed
	32-bit integers), the more recent the LSA.
	The sequence number 0x80000000 is reserved and unused.
Checksum	The checksum of the complete contents of the LSA,
	excluding the age field. The age field is excluded to allow
	the LSA age to increment without updating the checksum.
	The checksum is used to detect data corruption of an LSA.
	This corruption can occur while an LSA is being flooded,
	or while an LSA is being held in a router’s memory. The
	LSA checksum field cannot take on the value of zero; the
	occurrence of this value is a checksum failure.

	Cisco Content Services Switch Routing and Bridging Configuration Guide
OL-4580-01		3-35