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Bandwidth on SVI interface

Hi all,

the bandwidth on an SVI interface is showing as 1000000 kbit (1gbps) even though we have 20g etherchannels on this VLAN to other switches.

My question is, will this incorrect bandwidth setting have any affect on routing decisions that OSPF would make? i imagine the rxload and txload are based on the bandwidth setting and in our monitoring system I am seeing that the SVI is always maxed at 1gbps when i know it is not an issue because we have 20g etherchannels.

What is the recommendation for bandwidth settings on SVI's?

Thanks

Mario

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Yes, an "incorrect" bandwidth might lead OSPF to select an "incorrect" path as Cisco's OSPF implementation, uses "bandwidth" to compute the OSPF metric.

What you ought to set a SVI's bandwidth to depends on what you want it to represent.  For example, in theory, a SVI's bandwidth would be the aggregate of all the ports in the VLAN, but it's unlikely all those ports will be a path to an adjacent OSPF neighbor.  So, you might select the bandwidth to your OSPF neighbor, but that might be inaccurate if you have more than one in the VLAN.

You also can directly set OSPF cost.

Basically, one-size doesn't fit all, it's what makes most sense to you.  For example, you might want bandwidth to actually represent the aggregate bandwidth, for bandwidth usage analysis, and use OSPF cost to "engineer" your OSPF path selection.

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