Point-To-Point Support; Ospf Link Types - Extreme Networks Summit Summit24 Installation And User Manual

Interior Gateway Routing Protocols
Figure 31: Virtual link providing redundancy
Virtual link
ABR 1
Area 1

Point-to-Point Support

You can manually configure the OSPF link type for a VLAN. Table 55 describes the link types.
Table 55: OSPF Link Types
Link Type Number of Routers Description
Auto Varies
Broadcast Any
Point-to-point Up to 2
NOTE
The number of routers in an OSPF point-to-point link is determined per-VLAN, not per-link.
NOTE
All routers in the VLAN must have the same OSPF link type. If there is a mismatch, OSPF attempts to
operate, but may not be reliable.
190
Area 2
ABR 2
Area 0
ExtremeWare automatically determines the OSPF link
type based on the interface type. This is the default
setting.
Routers must elect a designated router (DR) and a
backup designated router (BDR) during
synchronization. Ethernet is an example of a
broadcast link.
Synchronizes faster than a broadcast link because
routers do not elect a DR or BDR. Does not operate
with more than two routers on the same VLAN. PPP
is an example of a point-to-point link. An OSPF
point-to-point link supports only zero to two OSPF
routers and does not elect a DR or BDR. If you have
three or more routers on the VLAN, OSPF will fail to
synchronize if the neighbor is not configured.
Area 3
EW_017
Summit24e3 Switch Installation and User Guide