Add GRE and MPLS encap-headers to network-instance/static

[dplore]

Change Scope

• Add GRE and MPLS encap-headers to network-instance/static
• This change is backwards compatible

Platform Implementations

While device implementations today widely support encapsulation of MPLS, GRE and MPLS into GRE packets this PR provides a method to configure a static next-hop-group for the purpose of encapsulation. Using next-hops for this purpose is a new feature being pursued from multiple device implementations.

Tree view

         +--rw static
         |  +--rw next-hop-groups
         |  |  +--rw next-hop-group* [name]
         |  |     +--rw name         -> ../config/name
         |  |     +--rw config
         |  |     |  +--rw name?   string
         |  |     +--ro state
         |  |     |  +--ro name?   string
         |  |     +--rw next-hops
         |  |        +--rw next-hop* [index]
         |  |           +--rw index     -> ../config/index
         |  |           +--rw config
         |  |           |  +--rw index?   -> ../../../../../../next-hops/next-hop/index
         |  |           +--ro state
         |  |              +--ro index?   -> ../../../../../../next-hops/next-hop/index
         |  +--rw next-hops
         |     +--rw next-hop* [index]
         |        +--rw index            -> ../config/index
         |        +--rw config
         |        |  +--rw index?                   string
         |        |  +--rw next-network-instance?   -> /network-instances/network-instance/config/name
         |        |  +--rw next-hop?                union
         |        |  +--rw nh-network-instance?     -> /network-instances/network-instance/config/name
         |        |  +--rw recurse?                 boolean
         |        |  +--rw metric?                  uint32
         |        |  +--rw preference?              uint32
         |        +--ro state
         |        |  +--ro index?                   string
         |        |  +--ro next-network-instance?   -> /network-instances/network-instance/config/name
         |        |  +--ro next-hop?                union
         |        |  +--ro nh-network-instance?     -> /network-instances/network-instance/config/name
         |        |  +--ro recurse?                 boolean
         |        |  +--ro metric?                  uint32
         |        |  +--ro preference?              uint32
         |        +--rw encap-headers
         |           +--rw encap-header* [index]
         |              +--rw index     -> ../config/index
         |              +--rw config
         |              |  +--rw index?   uint8
         |              |  +--rw type?    oc-aftt:encapsulation-header-type
         |              +--ro state
         |              |  +--ro index?   uint8
         |              |  +--ro type?    oc-aftt:encapsulation-header-type
         |              +--rw udp-v4
         |              |  +--rw config
         |              |  |  +--rw src-ip?         oc-inet:ipv4-address
         |              |  |  +--rw dst-ip?         oc-inet:ipv4-address
         |              |  |  +--rw dscp?           oc-inet:dscp
         |              |  |  +--rw src-udp-port?   oc-inet:port-number
         |              |  |  +--rw dst-udp-port?   oc-inet:port-number
         |              |  |  +--rw ip-ttl?         uint8
         |              |  +--ro state
         |              |     +--ro src-ip?         oc-inet:ipv4-address
         |              |     +--ro dst-ip?         oc-inet:ipv4-address
         |              |     +--ro dscp?           oc-inet:dscp
         |              |     +--ro src-udp-port?   oc-inet:port-number
         |              |     +--ro dst-udp-port?   oc-inet:port-number
         |              |     +--ro ip-ttl?         uint8
+        |              +--rw gre
+        |              |  +--rw config
+        |              |  |  +--rw src-ip?   oc-inet:ip-address
+        |              |  |  +--rw dst-ip?   oc-inet:ip-address
+        |              |  +--ro state
+        |              |     +--ro src-ip?   oc-inet:ip-address
+        |              |     +--ro dst-ip?   oc-inet:ip-address
+        |              +--rw mpls
+        |                 +--rw config
+        |                 |  +--rw traffic-class?   oc-mplst:mpls-tc
+        |                 |  +--rw mpls-label?      oc-mplst:mpls-label
+        |                 +--ro state
+        |                 |  +--rw traffic-class?   oc-mplst:mpls-tc
+        |                 |  +--rw mpls-label?      oc-mplst:mpls-label

Example configuration for static next-hops with 2 MPLS labeled inside GRE encapsulation

          "next-hops": {
            "next-hop": [
              {
                "config": {
                  "index": "Dest A-NH1",
                  "metric": 10,
                  "next-hop": "1.2.3.4"
                },
                "encap-headers": {
                  "encap-header": [
                    {
                      "config": {
                        "index": 1
                      },
                      "index": 1,
                      "type": "GRE",
                      "config": {
                        "dst-ip": "gre_ipv4_dst_def",
                        "src-ip": "gre_ipv4_src1",
                        "dscp": "gre_dscp",
                      }
                    }
                    {
                      "config": {
                        "index": 2
                      },
                      "index": 2,
                      "type": "MPLS",
                      "config": {
                        "traffic-class": 2,
                        "mpls-label":  100
                        }
                      },
                    {
                      "config": {
                        "index": 3
                      },
                      "index": 3,
                      "type": "MPLS",
                      "config": {
                        "traffic-class": 2,
                        "mpls-label":  200
                        }
                      }

                    ]
                  },
                 "index": "Dest A-NH1"
               },
            ]
          }

[OpenConfigBot]

No major YANG version changes in commit a0b5ad6

[dplore]

Updated the PR description to show the tree.

[dplore]

@robshakir ready for your review

[robshakir]

Suggested change

	using this leaf (src-ip) or if may be derived from
	using this leaf (src-ip) or it may be derived from

[robshakir]

It's not quite clear what this means. Do you intend to say that the source IP is set based on the interface the policy is applied to? I recall that there's some discussion of wanting to have policies that are not just applied to interfaces.

Also, is this widely supported?

[dplore]

Honestly, I cut and paste this from the existing aft definition for next-hop with GRE encapsulation, introduced at #1038

I read this intent as the src-ip for the encapsulation may be statically configured using this leaf. If not populated the src-ip is expected to be dynamically derived from the subinterface that the packet is forwarded from. If an implementation requires a static src-ip, then it should return an error if this is unspecified.

How does that sound for a description?

[dplore]

Updated description to be more explicit. @romeyod for any addition comment.