Vlan Interface drops

I need an explination of the Show Interface Vlan command if anyone can help me with this.

I am troubleshooting QOS issues on a switched network, and have found both output and input drops on vlan interfaces. Since a vlan interface is has no physical port associated with it, I am having a hard time understanding why the packets would be dropped. I am not seeing drops at any of the physical interfaces between the hosts in question, only at the vlan interface. The hosts are obviously on different subnets, and are routed via this vlan interface.

So if anyone could give an explination of the 'Show Interface Vlan' output drops coutner, or any other insight as to what conditions could precipitate this behavior, I would certainly appreciate it.

Jeff Sieber

Reply to
sieber
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What are the switches being used and their IOS / CATOS versions

Reply to
Merv

What are the switches being used and their IOS / CATOS versions

Reply to
Merv

You're saying that this is related to QoS. Did you attach a 'service-policy' to this VLAN interface then? If yes, using 'show policy interface Vlan output|input' will tell you wether packets are dropped due to policy.

Another reason for packet drops on the input could be due to process switching of high volume traffic. Check if CEF is running on that interface.

Kind regards, iLya

Reply to
Charlie Root

It a 3550 running IOS 12.1(11)EA1.

I used the term QOS a bit loosely. There is no service-policy on the VLAN Interface. Although this interface is routing a high volume (8Mb or more) of Multicast Video, and SNMP traffic. And yes, I checked and CEF is running on that interface.

Thanks, Jeff

Charlie Root wrote:

Reply to
sieber

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