Backup Links
Backup Links
How Backup Links Work
Limitations
■Each hub can monitor a single backup link (only one backup link can be configured on each hub). But, the hub may be at the remote end of one backup link and at the monitoring end of a backup link to a different hub.
■A given hub should be connected to the remote end of no more than two backup links. If it is functioning as the remote hub in more than two backup links, it may not be able to respond to the test packets fast enough when there is a high level of data traffic on the network.
This ability to respond may be improved by increasing the time between test packet transmissions on the monitoring hubs. For all the backup links in which the remote hub is involved, the time configured on the moni- toring hubs for those links should be increased by one second for each additional backup link beyond two links. Add one to this count if the remote hub is also functioning as a primary (monitoring) hub in a different link.
Additional Notes
■Any port on the hub can be used for either the primary link or the backup link.
■Any combination of media types can be used as a backup link by using the AUI port. This accepts fiber, thin coax, and twisted pair external transceivers.
■The primary link and the backup link cabling should be run over different paths (through different conduits, for example) to reduce the possibility that damage will occur to both cables simultaneously.
