Owen DeLong wrote:
You mean anywhere in the world. Calls to my number reach my cell phone no matter where I go.
You are confusing number portability and call forwarding.
Not exactly… He is confusing number portability and roaming.
Wrong. Mobility including, but not limited to, roaming (international roaming of mobile phones is assumed) needs 1) access foreign environment 2) route packets to foreign network Roaming today perform 1) by foreign network (often through a chain of AAA) and 2) by home carrier as call forwarding, which is very similar to IP mobility. As we are talking about "Calls to my number reach my cell phone", "call forwarding" is the most properly scoped explanation. It should be noted that many on this thread misunderstand that 2) destroys route aggregation. However, call forwarding from home carrier for roaming and mobility tunnel from home agent for IP mobility is performed by end system without burdening routing system of intermediate network and just scale. Instead, many have wrongly assumed a poor alternative to have a separate routing table entry for each mobile host in global routing table, which does not scale. Masataka Ohta