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New Member

VPN 3000 Concentrator and SNMP

We have some VPN 3000 concentrators in our network. We use "cacti", a variant of the MRTG tool to graph various things. Amongst them, we also graph circuit utilization of our Internet bandwidth.

My routers and PIXs work fine in this regard. However, I see that the VPN concentrators report their Public interface circuit speed as whatever they have negotiated as speed with the uplink. For example, if the Public interface has negotiated a 10/half-duplex with the WAN SDSL router, then it will report its circuit speed as 10 Mbps. If the concentrator negotiates the link speed as 100/full, it reports the circuit speed as 100 Mbps. In reality, both WAN circuits are T1 and therefore should have the circuit speed set to 1.544 Mbps.

This causes a problem when graphing because it never hits the right thresholds. For example, if I ask it to paint red in the graph after the utilization cross 80%, the calculation will be based on 10 Mbps or 100 Mbps (as 100%) and not 1.544 Mbps.

Can someone tell me how can I remedy this issue and have the circuit speed reported as the Link Rate set on the concentrator rather than its physical interface speed?


  • Security Management
New Member

Re: VPN 3000 Concentrator and SNMP

Set your utilzation threshold to 1.25% of a 100Mb interface. Since your interface will never make it as high as 80Mbps you have a figure out what 80% of the T1 link would be and have it paint red when it reaches that mark.

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