Hirschmann HiSecOS EAGLE30 - External Links State Database

Routing > OSPF > Diagnostics
Routing
344
RM GUI HiSecOS EAGLE20/30
Release 3.0 09/2015
8.17.5 External Links State Database
The table displays the contents of the external link state database, with an
entry for each unique link state ID. External links allow the area to connect to
destinations outside of the autonomous system. Routers pass information
about the external links throughout the network as link state updates.
 Table
Parameters Meaning
Type Displays the type of the link state advertisement. When the router detects
an external link state advertisement it enters the information in the table.
Possible values:
 asExternal
LSID Displays the Link State ID is an LS type-specific field containing either a
router ID or an IP Address. The value identifies the routing domain
described in the advertisement.
Possible values:
 Valid IPv4 address
Router ID Displays the router ID uniquely identifying the originating router,
Possible values:
 router ID
Sequence Displays the value of the sequence field in an LSA.
The router examines the contents or the LS checksum field whenever the
LS sequence number field indicates that 2 instances of an LSA are the
same. If there is a difference, the router considers the instance with the
larger LS checksum to be most recent.
Age Displays the age of the link state advertisement in seconds.
When the router creates the LSA it sets the LS age to
0 . As the routers
transmit the LSA across the network the routers increment the age by the
value specified in "Transmit Delay [s]". If a router receives 2 LSAs for the
same segment having identical LS sequence numbers and LS checksums,
then the router examines the age of the LSA. The router immediately
accepts LSA with MaxAge. Otherwise, the router accepts the LSA with the
smaller age.
Checksum Displays the contents of the checksum.
The field is a checksum of the complete contents of the LSA, except for the
age field. The age field of the advertisement increases as the routers
transmit the message across the network. Excluding the age field allows
routers to transmit the message without needing to update the checksum
field.