Backport gRPC client configuration (dp:url-open gRPC support) from 10.6.6 CD to the 10.6.0.x LTS stream

The gRPC configuration object, which defines the connection to a remote gRPC server for use in a stylesheet with the dp:url-open extension element, is currently only available in the DataPower Gateway 10.6.6 Continuous Delivery (CD) release (see IBM Docs: "Configuring gRPC connections to remote gRPC servers", 10.6.x). It is not available in the 10.6.0.x Long Term Support (LTS) stream.

We request that this capability be delivered in an upcoming 10.6.0.x LTS fix pack so that customers on the LTS support model can consume it.

Standards and technical foundation:

gRPC is not a proprietary or exotic protocol — it is built entirely on open, standardized technologies that DataPower already supports in the LTS stream:

• RFC 9113 — HTTP/2 (IETF, June 2022, obsoleting RFC 7540): gRPC is defined strictly as an application-layer protocol on top of standard HTTP/2 framing, streams, and flow control. DataPower 10.6.0.x LTS already ships an HTTP/2 implementation (HTTP/2 is supported on HTTP/HTTPS handlers and MPGW), so the transport layer required for gRPC is already present and supported in LTS.
• RFC 7541 — HPACK header compression: required by HTTP/2 and therefore already implemented in the LTS codebase.
• gRPC over HTTP/2 protocol specification ("PROTOCOL-HTTP2", github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md): the normative mapping of gRPC semantics (content-type application/grpc, length-prefixed messages, trailers-based status) onto HTTP/2. This is the exact specification the 10.6.6 CD feature implements.
• Protocol Buffers language specification (protobuf.dev): the .proto IDL and wire format used by the feature's Protocol Buffers definition file property.
• RFC 1951 (deflate) / RFC 1952 (gzip): the two message-compression algorithms already exposed by the CD feature — both long-standardized and already used elsewhere in DataPower.
• TLS (RFC 8446, TLS 1.3 / RFC 5246, TLS 1.2): gRPC connections are secured with the existing DataPower TLS client profile object; no new cryptographic machinery is required.
• gRPC is governed by the CNCF (Cloud Native Computing Foundation) and is the de-facto standard RPC protocol for cloud-native and Kubernetes-based microservices, used by projects such as Kubernetes, Istio, and Envoy.

The key point: because HTTP/2 (RFC 9113), HPACK, TLS, and gzip/deflate are all already present and supported in 10.6.0.x LTS, the gRPC client feature is an incremental application-layer capability on top of an already-supported LTS transport stack — not a new protocol stack. This materially reduces the risk normally associated with backporting new function into an LTS stream.