Ospf point-to-point links, Designated routers in multi-access networks, Figure 8 – Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) User Manual
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OSPF point-to-point links
FIGURE 8
OSPF operating in a network
OSPF point-to-point links
In an OSPF point-to-point network, where a direct Layer 3 connection exists between a single pair of
OSPF routers, there is no need for Designated and Backup Designated Routers, as is the case in
OSPF multi-access networks. Without the need for Designated and Backup Designated routers, a
point-to-point network establishes adjacency and converges faster. The neighboring routers
become adjacent whenever they can communicate directly. In contrast, in broadcast and
non-broadcast multi-access (NBMA) networks, the Designated Router and Backup Designated
Router become adjacent to all other routers attached to the network.
To configure an OSPF point-to-point link, refer to
“Configuring an OSPF network type”
Designated routers in multi-access networks
In a network that has multiple routers attached, OSPF elects one router to serve as the designated
router (DR) and another router on the segment to act as the backup designated router (BDR). This
arrangement minimizes the amount of repetitive information that is forwarded on the network by
forwarding all messages to the designated router and backup designated routers responsible for
forwarding the updates throughout the network.