D-Link DES-3326S - Manual (Page 164)

DES-3326S Layer 3 Fast Ethernet Switch User’s Guide
164 Switch Management and Operating Concepts
advertisements.
Table 5-24. Summary Link Advertisement
Autonomous Systems External Link Advertisements
Autonomous Systems (AS) link advertisements are Type 5 link
state advertisements. These advertisements are originated by
AS boundary routers. A separate advertisement is made for
each destination known to the router, that is external to the AS.
AS external link advertisements usually describe a particular
external destination. For these advertisements the Link State
ID field specifies an IP network number. AS external link
advertisements are also used to describe a default route.
Default routes are used when no specific route exists to the
destination. When describing a default route, the Link Stat ID
is always set the Default Destination address (0.0.0.0) and the
Network Mask is set to 0.0.0.0.
The format of the AS External Link Advertisement is shown
below: