This test verifies the functionality of policy-based forwarding (PF) to decapsulate GRE-encapsulated traffic. The test verified IPv4, IPv6 and MPLS encapsulated traffic. The test also confirms the correct forwarding of traffic not matching the decapsulation policy.

• featureprofiles/topologies/atedut_2.testbed

• DUT has an ingress port and an egress port.

                           |         |
      [ ATE Port 1 ] ----  |   DUT   | ---- [ ATE Port 2 ]
                           |         |
  

• ATE Port 1: Generates GRE-encapsulated traffic with various inner (original) destinations.

• ATE Port 2: Receives decapsulated traffic whose inner destination matches the policy.

1. Interfaces: Configure all DUT ports as singleton IP interfaces.

2. Static Routes/LSPs:

   • Configure an IPv4 static route to GRE decapsulation destination (DECAP-DST) to Null0.
   • Configure static routes for encapsulated traffic destinations IPV4-DST1 and IPV6-DST1 towards ATE Port 2.
   • Configure static MPLS label binding (LBL1) towards ATE Port 2. Next hop of ATE Port 1 should be indicated for MPLS pop action.
   • Configure static routes for destination IPV4-DST2 and IPV6-DST2 towards ATE Port 2.

3. Policy-Based Forwarding:

   • Rule 1: Match GRE traffic with destination DECAP-DST using destination-address-prefix-set and decapsulate.
   • Rule 2: Match all other traffic and forward (no decapsulation).
   • Apply the defined policy with to the ingress ATE Port 1 interface.

   TODO: OC model does not have a provision to apply decap policy at the network-instance level for traffic destined to device loopback interface (see Cisco CLI config exepmt below). Needs clarification and/or augmentation by vendors if required. PR #1150

   vrf-policy
     vrf default address-family ipv4 policy type pbr input DECAP-POLICY
   

• Push DUT configuration.

Traffic:

• Generate GRE-encapsulated traffic from ATE Port 1 with destinations matching DECAP-DST.
• Inner IPv4 destination should match IPV4-DST1.
• Inner-packet DSCP value should be set to 32.

Verification:

• Decapsulated IPv4 traffic is received on ATE Port 2.
• No packet loss.
• Inner-packet DSCP should be preserved.
• PF counters reflect decapsulated packets.

• Push DUT configuration.

Traffic:

• Generate IPv6 GRE-encapsulated traffic from ATE Port 1 with destinations matching DECAP-DST.
• Inner IPv6 destination should match IPV6-DST1.
• Inner-packet traffic-class should be set to 128.

Verification:

• Decapsulated IPv6 traffic is received on ATE Port 2.
• No packet loss.
• Inner-packet traffic-class should be preserved.
• PF counters reflect decapsulated packets.

• Push DUT configuration.

Traffic:

• Generate GRE-encapsulated IPv4-over-MPLS traffic from ATE Port 1 with destinations matching DECAP-DST.
• Encapsulated MPLS top label should match LBL1.
• Inner IPv4 packet DSCP should be set to 32.

Verification:

• Decapsulated IPv4 traffic is received on ATE Port 2.
• No packet loss.
• TTL should be taken from the outer GRE header, decremented by 1 and copied to egress IP packet header.
• Inner-packet DSCP should be preserved.
• PF counters reflect decapsulated packets.

• Push DUT configuration.

Traffic:

• Generate GRE-encapsulated IPv4-over-MPLS traffic from ATE Port 1 with destinations matching DECAP-DST.
• Encapsulated MPLS top label should match LBL1.
• Inner IPv6 packet traffic-class should be set to 128.

Verification:

• Decapsulated IPv6 traffic is received on ATE Port 2.
• No packet loss.
• TTL should be taken from the outer GRE header, decremented by 1 and copied to egress IP packet header.
• Inner-packet traffic-class should be preserved.
• PF counters reflect decapsulated packets.

• Push DUT configuration.

Traffic:

• Generate GRE-encapsulated MPLS traffic from ATE Port 1 with destinations matching DECAP-DST.
• MPLS packets will have 2 labels.
• Top label should match LBL1.
• MPLS second label can be any.
• MPLS EXP bit on both labels should be set to 4.

Verification:

• Decapsulated MPLS traffic is received on ATE Port 2.
• TTL should be taken from the outer GRE header, decremented by 1 and copied to egress MPLS packet header.
• No packet loss.
• PF counters reflect decapsulated packets.
• EXP should set to original value.

• Push DUT configuration.

Traffic:

• Generate GRE-encapsulated traffic from ATE Port 1 with destinations that match IPV4-DST1/IPV6-DST2.

Verification:

• Traffic is forwarded to ATE Port 2 unchanged.

paths:
    # match condition
    /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/ipv4/config/destination-address-prefix-set:
    # decap action
    /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/action/config/decapsulate-gre:
    # application to the interface
    /network-instances/network-instance/policy-forwarding/interfaces/interface/config/apply-forwarding-policy:
    # TODO: provision apply decap to network-instance level does not exist. Needs clarification and/or augmentation by vendors.

    # telemetry
    /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/state/matched-pkts:
    /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/state/matched-octets:

rpcs:
  gnmi:
    gNMI.Set:
      union_replace: true
      replace: true
    gNMI.Subscribe:
      on_change: true

• FFF