User Manual

OSPF and OSPFv3
362
M4200 and M4300 Series ProSAFE Managed Switches Web Management User Manual
The following table describes the nonconfigurable data that is displayed in the External Link
State Database (LSDB) table.
Options The Options field in the link state advertisement header indicates which
optional capabilities are associated with the advertisement. The options
are as follows:
• Q. This enables support for QoS traffic engineering.
• E. This describes the way AS external LSAs are flooded.
• MC. This describes the way IP multicast datagrams are forwarded
according to the standard specifications.
• O. This describes whether opaque LSAs are supported.
• V. This describes whether OSPF++ extensions for VPN/COS are
supported.
Table 135. OSPF External Link State Database Table
Field Description
Router ID The 32-bit integer in dotted-decimal format that uniquely identifies the
router within the autonomous system (AS). The router ID is set on the
IP Configuration page. To change the router ID you must first disable
OSPF. After you set the new router ID, you must reenable OSPF for the
change to take effect. The default value is 0.0.0.0, although this is not a
valid router ID.
LSA Type The format and function of the link state advertisement. LSA Type is
one of the following:
• ASBR Summary
• AS-external
• NSSA
• TMP2
LS ID The link state ID identifies the piece of the routing domain that is being
described by the advertisement. The value of the LS ID depends on the
advertisement's LS type.
Age The time since the link state advertisement was first originated, in
seconds.
Sequence The sequence number field is a signed 32-bit integer. It is used to
detect old and duplicate link state advertisements. The larger the
sequence number, the more recent the advertisement.
Checksum The checksum is used to detect data corruption of an advertisement.
This corruption can occur while an advertisement is being flooded, or
while it is being held in a router's memory. This field is the checksum of
the complete contents of the advertisement, except the LS age field.
Table 134. OSPF Link State Database (continued)
Field Description