The test verifies policy-forwarding(PF) when matching specific DSCP values in IPv4/IPv6 header and redirecting traffic to an indirect BGP next-hop.

2 right-most bits are used for this test with all the possibles combinations of 3 left-most DSCP bits: ...011.

• featureprofiles/topologies/atedut_4.testbed

• DUT has an ingress port (Port 1) and 2 egress ports combined.

                           |         | --eBGP-- | ATE Port 2 |
      [ ATE Port 1 ] ----  |   DUT   |          |            |
                           |         | -------- | ATE Port 3 |
  

• Traffic is generated from ATE Port 1.

• ATE Port 2 is used as the destination port for PF. eBGP peerings on this port announces BG4IE NH.

• ATE Port 3 is used as the fallback destination when PF NH routes are withdrawn.

1. All DUT Ports are configured as a singleton IP interfaces.

2. Static routes (ST1) to test IPv4 and IPv6 destination networks (IPV4-DST1/IPV6-DST1) are configured on DUT towards ATE Port 3.

3. eBGP session is configured on DUT port 2. Indirect /32 (IPV-NH-V4) and /128 (IPV-NH-V6) prefixes are announced via eBGP from ATE Port 2.

4. PF is configured on DUT port 1 to match the traffic marked with rightmost 2 bits set in DSCP to 11. PF action is to redirect to BGP-announced next-hops (IPV-NH-V4/IPV-NH-V6):

• List of DSCP values (6-bit) to be matched [3, 11, 19, 27, 35, 43, 51, 59]
• Matching rules for IPv6 should map the above 6-bit DSCP values to the leftmost 6-bits of IPv6 traffic-class.
• PF should permit the rest of the traffic.

Generate traffic on ATE Port 1 to test IPv4 and IPv6 destination networks (IPV4-DST1/IPV6-DST1) with DSCP/TC rightmost 2 bits set to 11. Generate flows for every DSCP value in the set [3, 11, 19, 27, 35, 43, 51, 59]. IPv6 flows should use TC 8-bit values [12, 44, 76, 108, 172, 163, 204, 236]

Verify:

• All traffic received on ATE Port 2.
• No packet loss when forwarding.
• Verify PF packet counters matching traffic generated.

Generate traffic on ATE Port 1 to test IPv4 and IPv6 destination networks (IPV4-DST1/IPV6-DST1) with DSCP/TC rightmost 2 bits set to 00. Generate flows for every DSCP/TC values in the set [0, 8, 16, 24, 32, 40, 48, 56]. IPv6 flows should use TC 8-bit values [0, 32, 64, 96, 128, 160, 192, 224]

Verify:

• All traffic received on ATE Port 3.
• No packet loss when forwarding.

Withdraw next-hop prefixes (IPV-NH-V4/IPV-NH-V6) from BGP announcement. Generate traffic on ATE Port 1 to test IPv4 and IPv6 destination (IPV4-DST1/IPV6-DST1) networks with DSCP/TC rightmost 2 bits set to 11. Generate flows for every IPv4 DSCP value in the set [3, 11, 19, 27, 35, 43, 51, 59] and IPv6 TC [0, 32, 64, 96, 128, 160, 192, 224].

Verify:

• All traffic received on ATE Port 3.
• Traffic follows fallbacks static routes (ST1).
• No packet loss when forwarding.

paths:
  # PF configuration 
  /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/ipv4/config/dscp-set:
  /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/ipv6/config/dscp-set:
  /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/action/config/next-hop:
  # application to the interface
  /network-instances/network-instance/policy-forwarding/interfaces/interface/config/apply-forwarding-policy:

  # 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

• MFF
• FFF