Simple IP and Mobile IP

Last updated: February 10, 2009

This section is only applicable to the lab application.

What is Simple IP and Mobile IP?

The IS-2000 network using SO33 (see Packet Data Service Configurations ) for high speed packet data transmission supports connections to the public network or a private network using either mobile IP or simple IP protocol.

A packet data session begins when the user invokes packet data service. A packet data session ends when the user or the network terminates packet data service. During a particular packet data session, the user may change locations (point of attachment).

For simple IP protocol, a wireless device must obtain a new IP address (and lose existing connections) every time it changes its point of attachment. That is, moving from the coverage area of one PDSN to another PDSN constitutes a change in packet data session because a new IP address is assigned by the new PDSN. A packet data session and a PPP session are concurrent in simple IP, that is, the existence of the packet data session is dependent upon a PPP session.
For mobile IP protocol, a wireless device is allowed to maintain the same IP address as it moves from link to link (network to network) and preserve existing connections during moves. That is, the packet data session can exist through several changes of the PPP session. The mobile IP allows the PPP session to be terminated and reestablished without the termination of the packet data session. A packet data session can span several PDSNs as long as the user continuously maintains mobility bindings at the Home Agent (the IP address is persistent).

How Does Test Set Support Simple IP?

The test set supports simple IP protocol with it's internal PDSN simulation (see Test Set Packet Data Network Emulation and Packet Data Service Example Procedure (via Simple IP) ).

How Does Test Set Support Mobile IP?

The test set provides two ways to support mobile IP protocol tests required to ensure compliance with the TIA/EIA-IS-835 standard. One way is by working together with an external PDSN (MOB-IP-SIM) provided by the Software Concepts, Inc. The other way is a simple way just to use Mobile IP Support in the test set.

Mobile IP Simulator

By working together with an external PDSN (MOB-IP-SIM), the mobile IP protocol stack is implemented in the MOB-IP-SIM. For details on the MOB-IP-SIM functionality and configurations, see the MOB-IP-SIM technical manual available on the web:

http://www.softwareconceptsinc.net/mip-5850.php

A typical connection diagram for a mobile IP solution is shown in Configuration for a Mobile IP Solution . An example procedure for establishing a packet data connection over Mobile IP is described in Packet Data Service Example Procedure (via Mobile IP) .

Configuration for a Mobile IP Solution

The External PDSN State is used to specify whether the PDSN simulation for packet data service is provided by the test set or by the external application (MOB-IP-SIM).

When the External PDSN State is set to Off , the mobile station's PPP connection is terminated by the test set, propagating the encapsulated IP packets directly to the ethernet interface (LAN port).
When the External PDSN State is set to On , the test set will forward the PPP octets delivered by RLP data to the external application (MOB-IP-SIM), which is responsible for actual termination of the PPP link and interpreting all protocol layers necessary to pass the end-to-end encapsulated IP packets directly onto the network (IP, UDP, MIP). See Packet Data Service Example Procedure (via Mobile IP) for an example setup.
- When the external MOB-IP-SIM is to supply the PDSN simulation, you must specify the External PDSN IP Address and the External PDSN TCP Port , then turn the External PDSN State to On. The test set attempts to establish a packet data connection with the MOB-IP-SIM over its LAN Port at the specified External PDSN IP Address and External PDSN TCP Port.
- When the external MOB-IP-SIM is providing PDSN service to mobile station for packet data transfer, the packet data counters (see Data Counters ) and Data Throughput Monitor (see Data Throughput Monitor ) provides a measure of the current (instantaneous), peak and average data rates in kilobits-per-second as well as the accumulations of IP packets and bytes both to and from the test set and the mobile station.
- As the external MOB-IP-SIM only includes the logging of these higher protocols (IP, UDP, MIP), it cannot display those messages of the lower protocols (RLP and IS-2000 air interface). When the External PDSN State is set to On the test set will extract the IP packets from the PPP octets so they can be logged using the Wireless Protocol Adviser (WPA).
- When the external MOB-IP-SIM is providing PDSN service to the mobile station, the mobile station's IP address is assigned by the MOB-IP-SIM. The setting of External PDSN IP Address is ignored and the ping to a DUT functionality does not work (see Ping ).

Mobile IP Support in Test Set

The test set also provides Mobile IP support without any external devices. Its work model can be described as follows. The test set processes the reverse Mobile IP related messages (MIP Agent Solicitation, MIP Registration Request) from Mobile Station and generate corresponding forward Mobile IP messages (MIP Agent Advertisement, MIP Registration Reply) to Mobile Station in order to pass the Mobile IP negotiation. After the Mobile IP negotiation, the DUT IP Address is assigned as Home Address to the DUT and the DUT use this IP address to do IP packet data transferring. For most of the Mobile IP related parameters in the forward Mobile IP messages, the test set uses either the fixed settings in the test set or the related parameter values gotten from the corresponding reverse Mobile IP messages.

Here the packet data service means an SO33 call.

When External PDSN State is Off , Internal Mobile IP State has effect. Switch the Internal Mobile IP State to On , the test set works in Mobile IP mode, in which Home Agent Shared Secret (Hex) must be consistent with the value configured in the DUT, otherwise, Mobile IP negotiation will fail. Switch the Internal Mobile IP State to Off, the test set works in Simple IP mode.

When External PDSN State is On , Internal Mobile IP State has no effect. In this case, the simulation of data network is provided by MOB-IP-SIM instead of the test set.

Compared with a DUT working with MOB-IP-SIM, the performance of data throughput between the test set and a DUT configured using Mobile IP can be greatly improved. This difference can be observable in Data Throughput Monitor measurement.