Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ユーザーズマニュアル

Virtual links are also used to repair a discontiguous backbone area. For example, in 

, if the connection between ABR1 and the backbone fails, the connection using 

ABR2 provides redundancy so that the discontiguous area can continue to communicate with 
the backbone using the virtual link.

Point-to-Point Support

You can manually configure the OSPF link type for a VLAN. 

 describes the link 

types.

The number of routers in an OSPF point-to-point link is determined 

per VLAN, not per link.

Auto

Varies

XCM8800 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

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.

Passive

A passive link does not send or receive OSPF packets.

ABR 1

ABR 2

EX_045

Virtual link