Mobile IP (or IP mobility) is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile node to move from one network to another network and maintain a permanent IP address.   The Mobile IP protocol allows location-independent routing of IP datagram on the Internet.  Mobile IP for IPv4 is described in IETF RFC 3344, and updates are added in IETF RFC 4721. Mobile IPv6, the IP mobility implementation for the next generation of the Internet Protocol, IPv6, is described in RFC 3775.

There are two entities involved in Mobile IP implementation. When the mobile node is away from its home network, a mobile node is associated with a care-of address by the foreign agent that identifies its current location and its permanent home address is associated with its home agent. Mobile IP determines how a mobile node registers with its home agent and how the home agent routes IP datagram to the mobile node through the establishment of Mobile IP tunnel. Greenpacket supports Mobile IP through the Mobile IP (MIP) client. It can be an optional component to handle Mobility Functionality and interworks with the Connection Manager (CM) for establishing the Mobile IP tunnel between the PDG and UE endpoints if Mobility Functionality is enabled.

Interworking WLAN (3GPP TS23.234), is a defined standard for the interworking between 3GPP networks and Wireless LAN (i.e. roaming between 3GPP networks and WLAN networks). I-WLAN allows scalability and flexibility in deploying secured, automatic and value added Wi-Fi access both in trusted and also in unmanaged or un-trusted hotspots (hotspots that are operated by neither the carrier nor its roaming partner). IWLAN primarily provides a useful mechanism to managed data offload, allowing Wi-Fi traffic to be tethered back to the 3GPP packet core network.

With IWLAN, operators retain visibility on service and content to Wireless LAN hot spots and ensure the same subscriber provisioning, authentication, and service authorization that are already in place for GSM/3G services with ease of integration towards backend systems. Authentication to the selected network is performed transparently without the need for user intervention (for example, the user entering a username and password every instance, it detects a Wi-Fi network). With I-WLAN, GSM carriers will use the subscriber identity module (SIM) credentials already carried in their subscribers’ mobile devices to perform Wi-Fi Authentication using EAP-SIM. Similarly, Universal Mobile Telecommunications Service (UMTS) carriers will use USIM credentials with Extensible Authentication Protocol Method for EAP-AKA as a form of Wi-Fi authentication. Greenpacket‘s iWLAN solution is implemented through the iWLAN client on the UE side that is compliant to 3GPP TS23.234 specifications.

Access Network Discovery and Selection Function (ANDSF) is an entity within an Evolved Packet Core (EPC) of the System Architecture Evolution (SAE) for 3GPP compliant mobile networks. ANDSF describes how the inter-system mobility between 3GPP access networks (such as 3G, HSPA or LTE) and non-3GPP access networks (such as WLAN, WiMAX, CDMA) provide policies and priorities to control the conditions for which a device (UE) connects to which wireless network.

The context of ANDSF offers a useful mechanism to complement dynamic data offloading. The motivation for implementing ANDSF is largely driven by the need for better bandwidth utilization.  Operators have the flexibility to manage context information in network discovery and selection procedures in push and/or pull mechanism with a policy management and control component. Instead of relying heavily on the policies enforced at the core network (backend), actual decision making process can be made real-time as a result of direct relation to the user activity at the device (UE). By selectively triggering the connection of device (UE) to a given threshold or the preferred available access network types based on inter-system mobility policies, the network load can be balanced or spread out to the availability of network radio resource at the point where congestion is likely to occur.

Wireless Internet Service Provider (WISPr) roaming was formed by Wi-Fi Alliance to facilitate inter-network roaming between wireless internet service providers (WISPs), similar to mobile phone users to roam between carriers.  This roaming framework allows using Wi-Fi compliant devices to roam into Wi-Fi enabled hotspots for public access and services. Subscriber’s credentials are generally, authenticated through a RADIUS server to support recommended Authentication, Authorization, and Accounting (AAA) to enable Wi-Fi roaming.

WISPr recommends the Universal Access Method (UAM) to facilitate WISP roaming. The UAM allows a subscriber to access WISP services through an Internet browser and Wi-Fi network interface on the roaming. Greenpacket’s ICMP is compatible with UAM and adds value with features like single touch automated sign-on, listing of preferred SSIDs as such.

Wireless Broadband Alliance(WBA) pioneered the second version of WISPr 2.0 global roaming specifications to aid wireless internet service providers (WISPs). WISPr 2.0 aims to provide seamless authentication between Wi-Fi networks and other access networks like GSM/UMTS/LTE, WIMAX through a web interface access (browser based captive portal) to address interoperability of EAP-based (802.1x) compliant networks. This simplifies the connectivity management by automating Wi-Fi offload through EAP-based networks (802.1x) over WISPr.

Greenpacket’s ICMP EAP enabled clients are currently tested to demonstrate seamless authentication roaming capability over WISPr 2.0 specification.