Point-To-Point Support - Extreme Networks ExtremeWare XOS Guide Manual

Figure 69: 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 68: OSPF link types
Link Type Number of Routers
Auto Varies
Broadcast Any
Point-to-point Up to 2
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
it may not be reliable.
ExtremeWare XOS 11.3 Concepts Guide
Area 2
ABR 2
Area 0
Table 68
Description
ExtremeWare XOS 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.
This type synchronizes faster than a broadcast link because routers do
not elect a DR or BDR. It does not operate with more than two routers
on the same VLAN. The Point-to-Point Protocol (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 designated router (DR) or
backup designated router (BDR). If you have three or more routers on
the VLAN, OSPF fails to synchronize if the neighbor is not configured.
A passive link does not send or receive OSPF packets.
Overview of OSPF
Area 3
EX_045
describes the link types.
549