Clarification on simple GLBP configuration

[news2010a]

Hi, can you confirm if the use of the command "glbp 1 weighting 100 lower 95" is necessary to accomplish the following:

Requirement:

"Configure GLBP between R1 F0/0 and R2 F0/0 interfaces. R2 should have the higher priority. R1 should be able to assume control if R4 priority decreases."

R1

int f0/0

glbp 1 ip 192.168.1.1

glbp 1 preempt

glbp 1 weighting track 1

R2:

int f0/0

glbp 1 ip 192.168.1.1

glbp 1 priority 105

glbp 1 preempt

glbp 1 weighting track 1

glbp 1 weighting 100 lower 95

track 1 ip route 10.0.0.1 0.0.0.0 reachability

So can you explain again what is the role of "glbp 1 weighting 100 lower 95"? I don't see why that would be necessary to accomplish this.

[tamassini]

Hi,

For the role of GLBP weighting see quoted from cisco GLPB command reference

Usage Guidelines
The weighting value of a virtual gateway is a measure of the forwarding capacity of the gateway. If a tracked interface on the router fails, the weighting value of the router may fall from the maximum value to below the lower threshold, causing the router to give up its role as a virtual forwarder. When the weighting value of the router rises above the upper threshold, the router can resume its active virtual forwarder role.
Use the glbp weighting track and track commands to configure parameters for an interface to be tracked. If an interface on a router goes down, the weighting for the router can be reduced by a specified value.

HTH.

BR,

Aliou