[Mellanox][Dual-Tor][DSCP remapping]Fix a test issue for the dualtor tunnel monitor for Nvidia platforms

[congh-nvidia]

Description of PR

Summary:
Fixes # (#9624)
On Nvidia platforms, when the inner/outer DSCPs are 2/2 or 6/6, the tunnel packet is not mapped based on the mapping configuration to queue 1 (they will be mapped to queue 2 and 6).
And we have confirmed with MSFT that such packets are not expected in production.
So, skip the queue check for them.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 201911
• 202012
• 202205
• 202305

Approach

What is the motivation for this PR?

Fix test issue (#9624)

How did you do it?

Skip the queue check in tunnel monitor on Nvidia platforms when dscp is 2/2 or 6/6

How did you verify/test it?

Run test on 4600C dualtor setup, passed.

Any platform specific information?

Only for Nvidia platforms.

Supported testbed topology if it's a new test case?

Documentation

[liat-grozovik]

@bingwang-ms kindly reminder. the test fix should be part of 202305.

[bingwang-ms]

If the inner DSCP is 2 or 6, the outer DSCP should be 0. Is that right? Why the tunnel_monitor doesn't work?

DSCP_TO_TC_MAP:

"DSCP_TO_TC_MAP": {
        "AZURE": {
            ......
            "1": "1",
            "0": "1",
            "3": "3",
            "2": "1",
            "5": "1",
            "4": "4",
            "7": "1",
            "6": "1",
            "9": "1",
            "8": "0",
            "51": "1",
}

TC_TO_DSCP_MAP:

 "TC_TO_DSCP_MAP": {
        "AZURE_TUNNEL": {
            "1": "0",
            "0": "8",
            "3": "2",
            "2": "2",
            "5": "46",
            "4": "6",
            "7": "48",
            "6": "6",
            "8": "33"
        }
    }

[congh-nvidia]

Hi @bingwang-ms ,
On Nvidia platforms, we have different implementation in dscp remapping. The inner dscp 2 and 6 are considered as invalid use cases and not handled according to the mapping configurations.

[liat-grozovik]

@bingwang-ms kindly reminder, this fix is needed also for 202305

[congh-nvidia]

Hi @bingwang-ms , could you approve the PR or let me know if you still have any concerns?
Thanks.

[bingwang-ms]

@congh-nvidia Sorry I missed the review. So what's the outer DSCP value if the inner DSCP is 2 or 6?

[congh-nvidia]

Hi @bingwang-ms , on Nvidia platforms the inner dscp 2/6 will be encapsulated with outer dscp 2/6 on the standby tor.

[mssonicbld]

Cherry-pick PR to 202311: #11299

[mssonicbld]

Cherry-pick PR to 202305: #11300