Reference Guide

Field Description
• TOS-capability or No TOS-capability is displayed depending
on whether the router can support Type of Service.
• DC or No DC is displayed depending on whether the
originating router can support OSPF over demand circuits.
• E or No E is displayed on whether the originating router can
accept AS External LSAs.
LS Type Displays the LSA’s type.
Link State ID Displays the Link State ID.
Advertising Router Identifies the router ID of the LSA’s originating router.
LS Seq Number Identifies the link state sequence number. This number enables you
to identify old or duplicate LSAs.
Checksum Displays the Fletcher checksum of the LSA’s complete contents.
Length Displays the length in bytes of the LSA.
Network Mask Displays the network mask implemented on the area.
Metrics Type Displays the external type.
TOS Displays the Type of Service (TOS) options. Option 0 is the only
option.
Metric Displays the LSA metric.
Forward Address Identifies the address of the forwarding router. Data traffic is
forwarded to this router. If the forwarding address is 0.0.0.0, data
traffic is forwarded to the originating router.
External Route Tag Displays the 32-bit field attached to each external route. The OSPF
protocol does not use this field, but you can use the field for external
route management.
Example
FTOS#show ip ospf 1 database external
OSPF Router with ID (20.20.20.5) (Process ID 1)
Type-5 AS External
LS age: 612
Options: (No TOS-capability, No DC, E)
LS type: Type-5 AS External
Link State ID: 12.12.12.2
Advertising Router: 20.31.3.1
LS Seq Number: 0x80000007
Checksum: 0x4cde
Length: 36
Network Mask: /32
Metrics Type: 2
TOS: 0
Metrics: 25
Forward Address: 0.0.0.0
External Route Tag: 43
LS age: 1868
970