Commands to see QoS applied?

[clive.fulton]

I'm using an ISR 4431 router. I know "show policy-map interface <INT>" will show me the overall policy map and classes. But are there commands that will show me what specific class maps are applied to given traffic? For example, can i specify a source and dest IP and see what class map is applied? can i see what dscp flag is present on specific traffic (if any)? and what protocol or application the router is classifying the traffic as?

[Giuseppe Larosa]

Hello @clive.fulton ,

show interface gi0/x

show policy-map interface gi0/x

ISR 4000 run IOS XE.

Hierachical QoS has been introduced in IOS 12.4(20)T

Joseph Doherty or other expests can help you

look for output drops in both commands

Consider this a starting point for this thread

Hope to help

Giuseppe

hint:

they have the ISR 4331 an internal fabric with multi GE support but ISR 4331 is not intended to support multilple 1GE ports at wire rate it is a branch router.

Hope to help

Giuseppe

[Joseph W. Doherty]

"Hierachical QoS has been introduced in IOS 12.4(20)T"

BTW, I recall that's when HQF was introduced, but I recall (?) pre-HQF CBWFQ also supported parent/child(/grandchild?) policies.

[Joseph W. Doherty]

You noted the platform but not the IOS and its licensed features.  Software based routers, like the 4k ISRs, QoS features can vary between IOS versions.

That said, I don't believe the answer is yes to any of your specific example questions or in general for a 4k ISR.

Years/decades ago (pre-HQF or even pre-CBWFQ), some (few?) platforms supported a command (possibly unique to WFQ) that would show some packet header information for packets currently queued, which might have provided some of the information you desire, but I believe that command is no longer provided.

Possibly your platform supports embedded packet capture, which might meet some of your information needs.

Otherwise, you're limited to just seeing packet count starts for various QoS stats, and being able to figure out how any particular packet will be handled by a CBWFQ policy map, much as you normally need to do for an ACL.

[vishalbhandari]

@clive.fulton 

Unfortunately, the ISR 4431 router does not have a direct command to show the specific class map applied to a given flow (e.g., source and destination IP). However, you can use show policy-map interface <INT> statistics to view the traffic counters for each class map, which can help you infer how traffic is classified. To see the DSCP flag on specific traffic, you can use show access-lists or configure an ACL with logging to capture the traffic details. For protocol or application classification, if NBAR is enabled, you can use show ip nbar protocol-discovery statistics or similar commands to identify how traffic is being classified by the router.