Quiz Entry - updated: 2026.07.14
What are the key mobility terms: home network, home address, visited network, care-of address, and correspondent?
These five terms describe the actors and addresses involved when a mobile device roams away from its home network.
| Term | Definition | Example |
|---|---|---|
| Home network | The permanent "home" of the mobile device — where its subscription lives | Swisscom or Salt network (your carrier) |
| Home address | The permanent address under which the device is always reachable | SIM-ID #1, or IP 128.119.40.186 |
| Visited network | A foreign network where the device currently is | Telecom Italia when traveling in Italy |
| Care-of address | A temporary address assigned in the visited network | IP 79.129.13.2, Cell-ID #10 |
| Correspondent | The party trying to communicate with the mobile device | Someone calling your phone |
The key insight: The home address never changes — it's like your permanent mailing address. The care-of address changes every time you roam to a new network. The challenge is connecting these two so that the correspondent can always reach you via your home address, even when you're somewhere else.
Go deeper:
Mobile IP (Wikipedia) — the protocol that names home address, care-of address, home/foreign agent and correspondent node — the exact vocabulary of this card.- RFC 5944 — IP Mobility Support for IPv4 (IETF) — the authoritative spec defining each term precisely.