Virtual link: Virtual Link
- In order to avoid loops between areas , OSPF stipulates that it is not allowed to advertise routing information directly between two non-backbone areas , and only allow routing information to be advertised within an area or between the backbone and non-backbone areas. Therefore, each ABR does not have to be connected to the backbone area . That is, all non-backbone areas must be connected to the backbone area, and the backbone area must also be continuous.
- However, due to factors such as network design, upgrades, mergers, and transformations , resulting in a non-standard regional architecture , which ultimately leads to incomplete routing learning , the solution is to use virtual links.
- However, the existence of virtual connections increases the complexity of the network , making troubleshooting more difficult. Therefore, virtual links should be avoided as much as possible in network planning.
- The virtual link is only used as a temporary method to repair the inevitable network topology problem .
- A virtual link can be seen as a sign that indicates whether a part of the network needs to be re-planned .
