Point-To-Point Support - Extreme Networks ExtremeWare 7.2e Installation And User Manual

Figure 47: Virtual link providing redundancy
Area 1

Point-to-Point Support

You can manually configure the OSPF link type for a VLAN. Table 42 describes the link types.
Table 42: OSPF Link Types
Link Type
Auto
Broadcast
Point-to-point
Passive
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.
ExtremeWare 7.2e Installation and User Guide
Virtual link
Area 2
ABR 1
Area 0
Number of Routers Description
Varies ExtremeWare automatically determines the OSPF link type based on
the interface type. This is the default setting.
Any Routers must elect a designated router (DR) and a backup designated
router (BDR) during synchronization. Ethernet is an example of a
broadcast link.
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.
A passive link does not send or receive OSPF packets.
ABR 2
Area 3
EW_017
Overview of OSPF
239