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New Member

Subinterfaces with and without service-policy

I'm battling to find a definitive answer to this, so thought I'd post.

If a physical FastE interface has multiple subinterfaces configured and all except one of the subinterfaces have service-policy config on them, what will happen to the traffic on the subinterface which isn't configured with service-policy when a queue arises?

Many thanks

Andrew

1 ACCEPTED SOLUTION

Accepted Solutions
New Member

Re: Subinterfaces with and without service-policy

If I understand your question correctly...

If QoS is not applied to

the sub interface, traffic will be best effort.

As you may already know, QoS is end to end. So, if traffic is not classfied or marked and it is priority(important) traffic, congestion and subsequent drops may occur...depending on the sub's traffic load.

HTH, if so please rate.

If I am wrong, someone please correct me.

4 REPLIES
New Member

Re: Subinterfaces with and without service-policy

Hi Andrew,

A router begins to queue packets when the number of packets that needs to be transmitted out an interface exceeds the output rate of that interface.

Queuing configuration only takes effect during periods of interface congestion, when the hardware queue has overflowed.

HTH

New Member

Re: Subinterfaces with and without service-policy

Thanks Erik.

I apologise for putting my question incorrectly. I'm really trying to establish the effect on traffic over the unconfigured subint when QoS comes into force (i.e. at congestion).

Regards,

Andrew

New Member

Re: Subinterfaces with and without service-policy

If I understand your question correctly...

If QoS is not applied to

the sub interface, traffic will be best effort.

As you may already know, QoS is end to end. So, if traffic is not classfied or marked and it is priority(important) traffic, congestion and subsequent drops may occur...depending on the sub's traffic load.

HTH, if so please rate.

If I am wrong, someone please correct me.

New Member

Re: Subinterfaces with and without service-policy

Erik,

Exactly what I needed to know. Duly rated.

Regards,

Andrew

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