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New Member

QoS (CoS) and Q-in-Q (dot1q-tunnel)

Hi,

I am looking for a document which describes the procedures and connections between QoS and Q-in-Q. Something like "NAT order of operation".

Points I am interested in are for example:

- Which CoS value is set in the outer VLAN tag?

- Which VLAN tag does 'mls qos trust cos' trust?

- Would the CoS value of the inner VLAN tag be inherited/passed to the outer VLAN tag?

I am mainly using Cat3560 and Cat3750 with IOS 12.2(25)SED1 IP-Base.

kind regards

Mark

2 REPLIES
Silver

Re: QoS (CoS) and Q-in-Q (dot1q-tunnel)

Policing function determines if the traffic level is within the specified profile (contract). Policing function allows either dropping out-of-profile traffic or marking the traffic down to a different Differential Services Code Point (DSCP) value to enforce contracted service level. DSCP is a measure of the Quality of Service (QoS) level of the packet. Along with DSCP, IP precedence and Class of Service (CoS) are also used to convey the QoS level of the packet

http://www.cisco.com/warp/public/473/134.html

New Member

Re: QoS (CoS) and Q-in-Q (dot1q-tunnel)

This answers is for 3750Metro

- Which CoS value is set in the outer VLAN tag?

The switch copy the inner cos

- Which VLAN tag does 'mls qos trust cos' trust?

The outer tag

- Would the CoS value of the inner VLAN tag be inherited/passed to the outer VLAN tag?

Yes.

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