D-Link DGS-3324SRi User Manual page 122

D-Link DGS-3324SRi Intelligent Stackable Gigabit Ethernet Switch
Network Links Advertisements
Network links advertisements are Type 2 link state advertisements. A network links advertisement is originated
for each transit network in the area. A transit network is a multi-access network that has more than one attached
router. The network links advertisement is originated by the network's Designated router. The advertisement
describes all routers attached to the network, including the Designated Router itself. The advertisement's Link
State ID field lists the IP interface address of the Designated Router.
The distance form the network to all attached routers is zero, for all TOS. This is why the TOS and metric fields
need not be specified in the network links advertisement.
The format of the Network Links Advertisement is shown below:
Field
Network Mask
Attached Router
Summary Link Advertisements
Summary link advertisements are Type 3 and 4 link state advertisements. These advertisements are originated
by Area Border routers. A separate summary link advertisement is made for each destination known to the
router, that belongs to the Autonomous System (AS), yet is outside the area.
Type 3 link state advertisements are used when the destination is an IP network. In this case the advertisement's
Link State ID field is an IP network number. When the destination is an AS boundary router, a Type 4
advertisement is used, and the Link State ID field is the AS boundary router's OSPF Router ID. Other that the
difference in the Link State ID field, the format of Type 3 and 4 link state advertisements is identical.
Network Link Advertisements
Link-State Age
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum
Network Mask
Attached Router
Description
The IP address mask for the network.
The Router Ids of each of the routers attached to the network. Only
those routers that are fully adjacent to the Designated Router (DR)
are listed. The DR includes itself in this list.
Network Link Advertisement
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