Configure traffic differentiation

Application awareness helps you use your Cross-Cloud Interconnect connections more efficiently by using differentiated services field codepoint (DSCP) for traffic differentiation.

You can configure traffic differentiation for outbound Cross-Cloud Interconnect data transfers using application awareness on Cloud Interconnect.

When you enable application awareness on your Cloud Interconnect and mark the DSCP in the IP headers of your outbound data transfers to map them to traffic classes, your outbound data transfers receive differentiated treatment on Cloud Interconnect.

Application awareness lets you do the following:

• Choose one of two policy types, either a strict priority policy or a bandwidth percentage policy, to specify how Cloud Interconnect treats your outbound data transfers that are classified into different traffic classes.

• Allocate your Cross-Cloud Interconnect outbound data transfer bandwidth among six different traffic classes.

• Use traffic shaping controls in addition to either policy type to set the maximum bandwidth that each traffic class can use on your Cross-Cloud Interconnect outbound data transfers.

The following sections describe application awareness on Cloud Interconnect and how to configure it for your Cross-Cloud Interconnect connection.

Contact your account team to enable application awareness on your Cross-Cloud Interconnect.

Before you begin

Before you begin, do the following:

• Understand the best practices when configuring Cloud Interconnect, in particular, for creating redundant Cloud Interconnect connections with sufficient capacity.

• Ensure that there is no network traffic on the Cross-Cloud Interconnect connection.

• Consider the following information about configuring application awareness:

  • DSCP in your outbound data traffic IP header determines the application awareness traffic class for providing traffic differentiation. Mark the DSCP in your outbound IP data traffic headers accordingly.

  • In order to mark a specific DSCP in your outbound Cloud Interconnect data transfers that originate from Google APIs, mark the same DSCP in your Google API request packets as your intended DSCP for the Google API response traffic. Google APIs echo back (copy) the DSCP from the corresponding customer request IP packet in their response traffic, which lets you control the DSCP for the Google API response traffic.

  • When you use Private Service Connect, the DSCP echo-back behavior is supported for Google APIs. You can control the DSCP in your Google API response traffic by setting the request DSCP accordingly. This lets you control the DSCP in your outbound data transfers from Google APIs that you connect to with Private Service Connect.

  • When you use Private Service Connect, DSCP echo-back isn't supported for published Virtual Private Cloud (VPC)-hosted services. Therefore, the DSCP in the response data traffic from published VPC-hosted services can't be controlled with the request traffic DSCP. Instead, the corresponding VPC-hosted service backends determine the DSCP in the response packets.

Traffic classes

Application awareness uses the concept of a traffic class, based upon DSCP ranges, to differentiate traffic on Cross-Cloud Interconnect. The following table describes the six traffic classes:

Available policy types

Application awareness on Cloud Interconnect offers two policy types to determine how outbound data transfers are differentiated on your Cloud Interconnect:

Strict priority

A strict priority policy type assigns a priority level to each traffic class for outbound data transfers. The highest-priority outbound data transfers are assigned to traffic class TC6, while the lowest-priority outbound data transfers are assigned to traffic class TC1.

Strict priority differentiation doesn't require that you specify class-specific configurations because the priority for each traffic class is prespecified. However, to prevent starving lower-priority traffic classes during congestion events, we recommend that you specify a traffic shaping profile to limit the maximum bandwidth used by each of your higher-priority traffic classes.

Bandwidth percentage

A bandwidth percentage policy type lets you specify the target bandwidth share that each traffic class can use during congestion events on your Cloud Interconnect. Assigning percentages to each traffic class helps ensure that each traffic class can use its specified share of Cloud Interconnect bandwidth during congestion events on your Cloud Interconnect.

If excess bandwidth is available because a traffic class isn't using its assigned share fully, the remaining bandwidth is shared equally among all other traffic classes.

Traffic shaping control

In addition to the two policy types, application awareness also provides traffic shaping controls that let you specify the maximum bandwidth that each traffic class can use. You can use traffic shaping controls with strict priority policies and with bandwidth percentage policies.

Configure a strict priority policy type

Use the following steps to configure a strict priority policy type.

gcloud beta compute interconnects application-awareness \
    configure-strict-priority-policy INTERCONNECT_NAME \
    --profile-description=DESCRIPTION \
    --enabled

{
  "aaiEnabled":true,
  "applicationAwareInterconnect":
    {
      "profileDescription": "DESCRIPTION",
      "strictPriorityPolicy":{}
  },
}

Configure a strict priority policy type with a traffic shaping profile

Optionally, you can configure a strict priority policy type along with a traffic shaping profile. We recommend that you use a traffic shaping profile to help ensure that lower-priority traffic classes aren't starved due to higher-priority traffic classes during congestion events.

Use the following steps to configure a strict priority policy type with a traffic shaping profile. Specify a numerical value representing the maximum bandwidth percentage for each included traffic class. You can define the traffic shaping profile for a subset or all 6 traffic classes, TC1 through TC6.

{
  "aaiEnabled": true,
  "applicationAwareInterconnect":
    {
      "profileDescription": "DESCRIPTION",
      "strictPriorityPolicy": {},
      "shapeAveragePercentages": [
          {
            "trafficClass": "TC1",
            "percentage": TC1_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC2",
            "percentage": TC2_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC3",
            "percentage": TC3_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC4",
            "percentage": TC4_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC5",
            "percentage": TC5_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC6",
            "percentage": TC6_SHAPE_PERCENTAGE
          }
        ]
    }
}

To prevent network failure, ensure that network control traffic, such as BGP and BFD, are included in the highest strict_policy priority class.

Configure bandwidth percentage

Use the following steps to configure the bandwidth percentage policy.

gcloud beta compute interconnects application-awareness \
    configure-bandwidth-percentage-policy INTERCONNECT_NAME \
    --profile-description=DESCRIPTION \
    --bandwidth-percentages="TC1=TC1_PERCENTAGE,TC2=TC2_PERCENTAGE,TC3=TC3_PERCENTAGE,TC4=TC4_PERCENTAGE,TC5=TC5_PERCENTAGE,TC6=TC6_PERCENTAGE" \
    --enabled

{
  "aaiEnabled": true,
  "applicationAwareInterconnect":
    {
      "profileDescription": "DESCRIPTION",
      "bandwidthPercentagePolicy": {
        "bandwidthPercentages": [
          {
            "trafficClass": "TC1",
            "percentage": TC1_PERCENTAGE
          },
          {
            "trafficClass": "TC2",
            "percentage": TC2_PERCENTAGE
          },
          {
            "trafficClass": "TC3",
            "percentage": TC3_PERCENTAGE
          },
          {
            "trafficClass": "TC4",
            "percentage": TC4_PERCENTAGE
          },
          {
            "trafficClass": "TC5",
            "percentage": TC5_PERCENTAGE
          },
          {
            "trafficClass": "TC6",
            "percentage": TC6_PERCENTAGE
          }
        ]
    }
  }
}

Configure bandwidth percentage with a traffic shaping profile

Optionally, you can configure a bandwidth percentage policy along with a traffic shaping profile. A traffic shaping profile helps you set the maximum bandwidth that each traffic class can consume.

Use the following steps to configure a bandwidth percentage policy with a traffic shaping profile. A nonzero value must be specified for each traffic class, and the bandwidth percentages for all traffic classes must sum up to 100.

{
  "aaiEnabled": true,
  "applicationAwareInterconnect":
    {
      "profileDescription": "DESCRIPTION",
      "bandwidthPercentagePolicy": {
        "bandwidthPercentages": [
          {
            "trafficClass": "TC1",
            "percentage": TC1_PERCENTAGE
          },
          {
            "trafficClass": "TC2",
            "percentage": TC2_PERCENTAGE
          },
          {
            "trafficClass": "TC3",
            "percentage": TC3_PERCENTAGE
          },
          {
            "trafficClass": "TC4",
            "percentage": TC4_PERCENTAGE
          },
          {
            "trafficClass": "TC5",
            "percentage": TC5_PERCENTAGE
          },
          {
            "trafficClass": "TC6",
            "percentage": TC6_PERCENTAGE
          }
        ]
    },
      "shapeAveragePercentages": [
          {
            "trafficClass": "TC1",
            "percentage": TC1_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC2",
            "percentage": TC2_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC3",
            "percentage": TC3_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC4",
            "percentage": TC4_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC5",
            "percentage": TC5_SHAPE_PERCENTAGE
          },
          {
            "trafficClass": "TC6",
            "percentage": TC6_SHAPE_PERCENTAGE
          }
        ]
    }
}

To prevent network failure, ensure that network control traffic, such as BGP and BFD, are included in the appropriate bandwidth percentage configuration.

Delete traffic differentiation policies

To delete traffic differentiation policies, use the following steps.

gcloud beta compute interconnects application-awareness delete INTERCONNECT_NAME

{
  "applicationAwareInterconnect":
  {
    "profileDescription": null,
    "strictPriorityPolicy": null,
    "bandwidthPercentagePolicy": null,
    "shapeAveragePercentages": null
  }
}

Turn off traffic differentiation

To turn off traffic differentiation, use the following steps:

gcloud beta compute interconnects application-awareness update INTERCONNECT_NAME \
    --no-enabled

{
  "aaiEnabled": false
}

What's next

• View Cloud Interconnect Monitoring metrics