Extreme Networks 200 Series - Manual (Page 216)

214 Summit 200 Series Switch Installation and User Guide
Interior Gateway Routing Protocols
Figure 36: Virtual link providing redundancy
Point-to-Point Support
You can manually configure the OSPF link type for a VLAN. Table 62 describes the link types.
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.
Table 62: OSPF Link Types
Link Type Number of Routers Description
Auto Varies ExtremeWare automatically determines the OSPF link
type based on the interface type. This is the default
setting.
Broadcast Any Routers must elect a designated router (DR) and a
backup designated router (BDR) during
synchronization. Ethernet is an example of a
broadcast link.
Point-to-point Up to 2 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.
ABR 1 ABR 2
EW_017
Area 2
Area 1 Area 0 Area 3
Virtual link