Marked traffic and default QoS settings

[mohammed hashim]

Hi,

when you do marking on one router, and there is another router having default settings (not configured with QoS) receiving this traffic, will it automatically prefer packets marked with high IP Precedence or DSCP, or we have to explicitly configure classes those do bandwidth or priority reservation for the marked traffic,,, etc

[chrihussey · Accepted solution]

Cisco routers do not by default perform QoS functions (prioritization, allotted bandwidth, policing, etc.). It must be configured.

Regards.

[mohammed hashim]

Thank you sir for your reply,

I got it.

[Joseph W. Doherty]

Generally, Cisco routers, by default, do not provide any special treatment for ToS tagged packets, however I know of one exception.

It used to be, Cisco routers supporting serial interfaces running at T1/E1 speeds, by default, enabled WFQ, and the older WFQ did provide higher packet prioritization based on the packet's ToS IPPrec setting.

[Dennis Mink]

NO it will not.  DSCP settings will need to be honored across every device in the path.