TCP Three-Way Handshake Network Diagram Examples with IP Addresses

Tech architecture infographic titled "TCP Three-Way Handshake" using archetype PROTOCOL HANDSHAKE, for a mid-level developer audience. Show a hand-drawn whiteboard style network diagram in a cool blue and cyan palette, editorial developer-blog illustration, isometric or flat tech-diagram style, vector-clean infographic layout. Depict clearly labeled boxes connected by directional arrows: Client Host, DNS Resolver, Internet / Router, Server Host, and optional Application Service box behind the server for context. Also include small supplemental labeled boxes for Browser, API, DB, Cache, and Queue as generic tech-component references, each with an icon, canonical English name, and a one-line English role description, but keep the main focus on the TCP handshake between client and server. Use generic cloud and network icons only, no vendor branding. Include subtle example IP addresses visually inside the endpoint boxes such as client private IP and server public IP to match network-diagram search intent.

Main numbered exchange flow must be technically accurate and visually dominant:
1) Client Host box: icon of laptop, label "Client Host", role "Initiates a TCP connection to the server." Include source ephemeral port and client IP example.
2) Server Host box: icon of rack server, label "Server Host", role "Listens on a TCP port and accepts new connections." Include destination port such as 443 or 80 and server IP example.
3) Arrow from Client Host to Server Host labeled "SYN, Seq=x".
4) Arrow from Server Host to Client Host labeled "SYN-ACK, Seq=y, Ack=x+1".
5) Arrow from Client Host to Server Host labeled "ACK, Ack=y+1".
6) Optional next arrow labeled "TCP connection established" followed by a lighter application-data arrow labeled either "HTTPS request" or "HTTP request" depending on the depicted port.

For every box, include an icon, a name, and one-line role description in English:
- Browser — "User agent that opens a network connection."
- API — "Application endpoint reached after TCP is established."
- DB — "Persistent storage used by the application."
- Cache — "Fast temporary store for repeated reads."
- Queue — "Asynchronous message buffer for background work."
These supporting boxes should be secondary and connected with arrows from the Application Service or API box, with labels such as "HTTP request", "SQL query", "cache lookup", "enqueue job", "JSON response" where appropriate, without implying they are part of the TCP handshake itself.

Add TCP state hints near the main endpoints in small callouts: "CLOSED → SYN-SENT" on client, "LISTEN → SYN-RECEIVED → ESTABLISHED" on server, "ESTABLISHED" on both after final ACK. Optionally show packet fields in compact notation: source IP, destination IP, source port, destination port, flags SYN / ACK. Keep protocol names in canonical English form: TCP, HTTPS, HTTP.

Add a numbered legend 1-7 in English walking through the lifecycle:
1. Client selects an ephemeral source port and sends a TCP SYN.
2. SYN carries the client initial sequence number.
3. Server in LISTEN state receives SYN and allocates connection state.
4. Server replies with SYN-ACK containing its own sequence number and acknowledgment.
5. Client verifies the acknowledgment and sends final ACK.
6. Both sides enter ESTABLISHED and can exchange application data.
7. Application traffic such as HTTPS or HTTP begins after the handshake.

Visual style notes: whiteboard marker outlines, sketch arrows, neat handwritten-tech aesthetic, cyan highlights for packet direction, cool blue containers, soft grid or faint whiteboard background, clear spacing, high readability, balanced composition, not an audited or security-guarantee diagram. All text MUST be written in English (array). Every heading, label, caption, legend and metric name in the image must be in English — not English. Spell each English word correctly using English characters and diacritics. Numbers stay as digits, no real cloud-vendor logos (AWS / GCP / Azure) — use generic cloud icons, no watermarks No real cloud-vendor logos (AWS, GCP, Azure) beyond generic cloud icons. Common protocol names (HTTPS, TCP, JWT, OAuth, REST, GraphQL) stay in canonical English form. No security-claim overstatements (do not present diagrams as audited reference architectures).