Backup line configuration

Backup line configuration

1. Enable the ISDN line after the main link is Down

1. Configure the backup line (in the main interface mode ):

Router (config-if) # backup interface

2. Configure backup latency (in the interface mode of the main interface ):

Router (config-if) # backup delay {enable-delay | never} {disable-delay | never}

Here: enable-delay indicates the time interval at which backup is initiated after the main interface is Down;

Disable-delay indicates the interval at which the backup link is closed after the master link is restored.

2. When the load on the master link reaches the set value, the backup link is enabled for simultaneous transmission.

1. Configure the backup line (in the main interface mode ):

Router (config-if) # backup interface

2. Configure the load parameters (in the main interface mode ):

Router (config-if) # backup load

Where: x indicates that the backup link is enabled when the load on the primary link reaches x % of the bandwidth of the primary link;

Y indicates that the backup link is disabled when the total link load reaches the bandwidth of the master link at y %.

3. You can also use logical interfaces as backups.

4. Use Floating Static Route for backup

By changing the management distance (AD) of static routing, the static routing on the backup link has a high AD value. When the active link is in normal state, the backup link is automatically enabled when the active link is down because of its low AD value.

Example:

Master link route: Ip router 172.16.254.0 255.255.255.0 Serial 0

Backup link route: Ip router 172.16.254.0 255.255.255.0 Serial 1 20

Note:

1. When the AD values of the two Link Static routes are set to the same, load balancing of other values of the static routes can be achieved.

2. Two default routes with different egress paths. When the AD value is different, the backup can be implemented like the static route above; but when the AD value is the same, the so-called "default route and other value load balancing" cannot be implemented, but it will only take effect for the default route first configured.

FW: Note:

1. When the AD values of the two Link Static routes are set to the same, load balancing of other values of the static routes can be achieved.

2. Two default routes with different egress paths. When the AD value is different, the backup can be implemented like the static route above; but when the AD value is the same, the so-called "default route and other value load balancing" cannot be implemented, but it will only take effect for the default route first configured.

What is the difference between the link and the exit? Can you explain the meaning of the second sentence!

FW: You have two Internet outlets connected to different ISPs and your router s0 and s1 respectively,

If your configuration is:

Ip router 0.0.0.0 0.0.0.0 s0

Ip router 0.0.0.0 0.0.0.0 s1

Then, your Internet egress only uses s0, because the second configuration does not take effect. Because

Ip router 0.0.0.0 0.0.0.0 s0

It is a default route, and only the default route configured first takes effect.

Ip router 0.0.0.0 0.0.0.0 s1

It does not work. This is: the so-called "Default routing and other value Load Balancing" cannot be achieved ".

If your s0 and s1 are connected to the same network segment (172.16.0.0/16), and your configuration is as follows:

Ip router 172.16.0.0 255.255.0.0 s0

Ip router 172.16.0.0 255.255.0.0 s1

At this time, when you reach the destination CIDR Block 172.16.0.0/27, both s0 and s1 ports will be used, because the above two statements are configured with Static Routing, not the default routing. This is called Static Routing and other value load balancing.

FW: there is an error on it,

"At this time you go to the target CIDR Block 172.16.0.0/27" should be changed:

"At this time you go to the destination CIDR Block 172.16.0.0/16 ".

FW: Let's talk about it again.

Link: generally refers to the physical line connecting the router and other devices.

Egress: generally refers to the network line connected to the entire network or local network and the external network. It is usually used to specify the physical connection between an internal network and an ISP.

Article entry: csh responsible editor: csh