2nd/10_Wiki/Topics/Other/Protocols.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-protocols	Protocols	10_Wiki/Topics	verified	self	Communication Protocols Network Protocols Wire Protocols	none	A	0.9	applied	networking protocols systems MCP		2026-05-10	pending	language framework multi HTTP-gRPC-MCP

Protocols

매 한 줄

"매 communicating parties 가 매 따라야 하는 rules 의 명시". 매 syntax (frame format), 매 semantics (meaning of fields), 매 timing (sequencing) 의 3 axes 로 정의. 매 2026 의 hot stack: HTTP/3 (QUIC), gRPC, MCP (Model Context Protocol), WebSocket, MQTT 5.

매 핵심

매 protocol 의 layers

• Physical / Link: Ethernet, Wi-Fi 7, 5G NR.
• Network: IPv6 (default 2026), IPv4 legacy.
• Transport: TCP, UDP, QUIC.
• Application: HTTP/3, gRPC, MCP, MQTT, AMQP.

매 design dimensions

• Stateful vs stateless: 매 server-side state 보관 여부.
• Sync vs async: 매 request-response vs publish-subscribe.
• Push vs pull: 매 server-initiated vs client-initiated.
• Text vs binary: 매 human-readable vs efficient.
• Versioning: 매 backward / forward compatibility 의 strategy.

매 응용

1. Web: HTTP/3 over QUIC — 매 default.
2. AI tools: MCP (Anthropic 2024) 매 LLM ↔ tool 의 universal.
3. Microservices: gRPC 매 internal RPC.
4. IoT: MQTT 5 매 lightweight pub-sub.
5. Realtime: WebSocket / WebTransport.

💻 패턴

MCP server (Anthropic, 2026 standard)

from mcp.server import Server
from mcp.types import Tool, TextContent

server = Server("knowledge-base")

@server.list_tools()
async def tools():
    return [Tool(
        name="query",
        description="Query the KB",
        inputSchema={
            "type": "object",
            "properties": {"q": {"type": "string"}},
            "required": ["q"],
        },
    )]

@server.call_tool()
async def call(name, args):
    return [TextContent(type="text", text=search(args["q"]))]

gRPC service (.proto + Python)

// kb.proto
syntax = "proto3";
service KB {
  rpc Query(QueryRequest) returns (stream QueryChunk);
}
message QueryRequest { string q = 1; }
message QueryChunk { string text = 1; bool done = 2; }

# server.py
import grpc, kb_pb2_grpc, kb_pb2

class KBServicer(kb_pb2_grpc.KBServicer):
    def Query(self, request, context):
        for chunk in stream_search(request.q):
            yield kb_pb2.QueryChunk(text=chunk, done=False)
        yield kb_pb2.QueryChunk(done=True)

HTTP/3 client (QUIC)

# httpx + h2/h3
import httpx

async with httpx.AsyncClient(http2=True, http3=True) as client:
    r = await client.get("https://api.example.com/v1/users")
    print(r.http_version)  # "HTTP/3"

WebSocket realtime

import asyncio
import websockets

async def handler(ws):
    async for msg in ws:
        await ws.send(f"echo: {msg}")

async def main():
    async with websockets.serve(handler, "0.0.0.0", 8765):
        await asyncio.Future()  # run forever

MQTT 5 pub-sub (IoT)

import paho.mqtt.client as mqtt

def on_message(client, userdata, msg):
    print(f"{msg.topic}: {msg.payload.decode()}")

client = mqtt.Client(protocol=mqtt.MQTTv5)
client.on_message = on_message
client.connect("broker.example.com", 1883)
client.subscribe("sensors/+/temperature")
client.loop_forever()

Protocol negotiation (capabilities handshake)

# Common pattern: client sends supported versions, server picks highest mutual
def negotiate(client_versions: set[str], server_versions: set[str]) -> str:
    common = client_versions & server_versions
    if not common:
        raise ProtocolError("no compatible version")
    return max(common, key=lambda v: tuple(map(int, v.split("."))))

매 결정 기준

Scenario	Protocol
매 LLM ↔ tools	MCP
매 internal RPC, polyglot	gRPC over HTTP/2
매 public web API	HTTP/3 + JSON / OpenAPI
매 realtime browser	WebSocket / WebTransport
매 IoT constrained	MQTT 5 / CoAP
매 message queue	AMQP 1.0 / Kafka
매 streaming chat	Server-Sent Events / WebSocket

기본값: 매 public = HTTP/3 + JSON, 매 internal = gRPC, 매 LLM tools = MCP.

🔗 Graph

• 부모: Distributed-Systems
• 변형: HTTP · gRPC · MCP
• 응용: API-Design · Microservices · 클라우드 인프라 및 IaC 운영 표준
• Adjacent: Interoperability

🤖 LLM 활용

언제: 매 protocol selection, 매 wire format debugging, 매 backward-compat strategy review. 언제 X: 매 single-process in-memory calls — 매 protocol 무용.

❌ 안티패턴

• Custom snowflake protocol: 매 in-house wire format 매 ecosystem 의 X.
• No version negotiation: 매 deploy mismatch → cascade failure.
• Stateful with no session: 매 load balancer 매 sticky session 강제 → scaling pain.
• Chatty protocols: 매 N round trips 매 single op → latency.

🧪 검증 / 중복

• Verified (RFC 9114 HTTP/3, 9000 QUIC; gRPC.io; Anthropic MCP spec 2024; OASIS MQTT 5; OASIS AMQP 1.0).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — protocol layers + 2026 modern stack (MCP, HTTP/3, gRPC)