Test MPLS-in-UDP encapsulation using gRIBI to create AFT entries that match IPv6 traffic and encapsulate it with MPLS labels inside UDP packets with IPv6 outer headers. The test validates that the DUT correctly implements RFC 7510 MPLS-in-UDP encapsulation with configurable UDP destination ports.

ATE port-1 <——> port-1 DUT

DUT port-2 <——> port-2 ATE

• featureprofiles/topologies/atedut_4.testbed

The test uses the following key parameters:

# MPLS-in-UDP configuration
mpls_label = 100
outer_ipv6_src = "2001:db8::1"
outer_ipv6_dst = "2001:db8::100"
outer_dst_udp_port = 6635  # RFC 7510 standard MPLS-in-UDP port
outer_ip_ttl = 64
outer_dscp = 10
inner_ipv6_prefix = "2001:db8:1::/64"

# Static ARP configuration for gRIBI next hop resolution
magic_ip = "192.168.1.1"
magic_mac = "02:00:00:00:00:01"

• Apply VRF selection policy to DUT port-1 to route traffic to the DEFAULT network instance
• Set up basic static routing infrastructure using gRIBI to forward encapsulated packets to port-2. This uses static IPv6 routes (not BGP or ISIS) configured via gRIBI AFT entries to establish the forwarding path for MPLS-in-UDP encapsulated packets.

Basic routing infrastructure AFT entries:

# Static IPv6 route for encapsulated packet forwarding
IPv6Entry {2001:db8::100/128 (DEFAULT VRF)} -> NHG#400 (DEFAULT VRF) -> {
  {NH#300, DEFAULT VRF, interface: port-2, mac: magic_mac}
}

Install the following MPLS-in-UDP encapsulation AFT entries:

# MPLS-in-UDP encapsulation entries
IPv6Entry {2001:db8:1::/64 (DEFAULT VRF)} -> NHG#2001 (DEFAULT VRF) -> {
  {NH#1001, DEFAULT VRF}
}

NH#1001 -> {
  encap_headers {
    encap_header {
      index: 1
      mpls {
        pushed_mpls_label_stack: [100]
      }
    }
    encap_header {
      index: 2
      udp_v6 {
        src_ip: "2001:db8::1"
        dst_ip: "2001:db8::100"
        dst_udp_port: 6635
        ip_ttl: 64
        dscp: 10
      }
    }
  }
}

Send IPv6 packets from ATE port-1 to DUT port-1 with:

• Source IPv6: 2001:0db8::192:0:2:2 (OTG port-1)
• Destination IPv6: 2001:db8:1:: (matches inner_ipv6_prefix)
• DSCP: 10
• UDP payload with random source/destination ports

Validate that ATE port-2 receives MPLS-in-UDP encapsulated packets with:

Outer IPv6 Header:

• Source IP: 2001:db8::1
• Destination IP: 2001:db8::100
• Hop Limit: 64
• Traffic Class: DSCP 10

UDP Header:

• Source Port: random, no need to validate
• Destination Port: 6635 (RFC 7510 standard)
• Protocol: UDP (17)

MPLS Header (inside UDP payload):

• Label: 100
• Bottom of Stack: 1 (true)
• TTL: 99 (decremented from inner packet TTL of 100)

Inner IPv6 Packet:

• Original IPv6 packet with decremented hop limit

1. Positive Test: Verify traffic flows successfully when MPLS-in-UDP entries are installed
   • Send traffic matching the IPv6 prefix 2001:db8:1::/64
   • Validate 0% packet loss
   • Confirm packets are properly encapsulated and forwarded
2. Negative Test: Verify traffic fails when MPLS-in-UDP entries are removed
   • Delete the gRIBI entries in reverse order
   • Send the same traffic
   • Validate 100% packet loss (no forwarding path)

The test performs detailed packet capture validation:

1. Capture Analysis: Uses OTG packet capture on port-2 to analyze encapsulated packets
2. Header Parsing: Validates both gopacket parsing and manual byte-level parsing of UDP headers
3. MPLS Validation: Decodes MPLS header from UDP payload and validates label, BoS bit, and TTL
4. Error Detection: Identifies common issues like incorrect UDP ports or malformed MPLS headers

• RFC 7510 Compliance: DUT must use UDP destination port 6635 for MPLS-in-UDP encapsulation
• Proper Encapsulation: Inner IPv6 packets are encapsulated with MPLS label 100 inside UDP
• Header Preservation: DSCP and TTL values are correctly set in outer headers
• Forwarding: Encapsulated packets are properly routed to the egress port

• FFF (supports gRIBI and MPLS-in-UDP encapsulation)

paths:
  ## Config paths
  /network-instances/network-instance/policy-forwarding/policies/policy/config/policy-id:
  /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/config/sequence-id:
  /network-instances/network-instance/policy-forwarding/policies/policy/rules/rule/action/config/network-instance:

  ## State paths
  /network-instances/network-instance/afts/next-hop-groups/next-hop-group/state/id:
  /network-instances/network-instance/afts/next-hop-groups/next-hop-group/next-hops/next-hop/state/index:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/state/index:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/state/type:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/mpls/state/mpls-label-stack:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/src-ip:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/dst-ip:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/src-udp-port:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/dst-udp-port:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/ip-ttl:
  /network-instances/network-instance/afts/next-hops/next-hop/encap-headers/encap-header/udp-v6/state/dscp:
  /interfaces/interface/subinterfaces/subinterface/ipv4/neighbors/neighbor/state/link-layer-address:

rpcs:
  gnmi:
    gNMI.Set:
    gNMI.Subscribe:
  gribi:
    gRIBI.Modify:
    gRIBI.Flush: