Cisco ASR 5000 Series, Обзор продукта

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CDMA2000 Wireless Data Services
Understanding Simple IP and Mobile IP ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
Proxy Mobile IP
Proxy Mobile IP provides mobility for subscribers with MNs that do not support the Mobile IP protocol stack.
For subscriber sessions using Proxy Mobile IP, R-P and PPP sessions get established as they would for a Simple IP
session. However, the PDSN/FA performs Mobile IP operations with an HA (identified by information stored in the
subscriber‘s profile) on behalf of the MN while the MN performs only Simple IP processes. The protocol details are
similar to those displayed in figure earlier for Mobile IP.
The MN is assigned an IP address by either the PDSN/FA or the HA. Regardless of its source, the address is stored in a
Mobile Binding Record (MBR) stored on the HA. Therefore, as the MN roams through the service provider‘s network,
each time a hand-off occurs, the MN will receive the same IP address stored in the MBR on the HA.
Note that unlike Mobile IP-capable MNs that can perform multiple sessions over a single PPP link, Proxy Mobile IP
allows only a single session over the PPP link. In addition, simultaneous Mobile and Simple IP sessions will not be
supported for an MN by an FA currently facilitating a Proxy Mobile IP session for the MN.
How Proxy Mobile IP Works
This section contains call flows displaying successful Proxy Mobile IP session setup scenarios. Two scenarios are
described based on how the MN receives an IP address:
Scenario 1: The AAA server specifies an IP address that the PDSN allocates to the MN from one of its locally
configured static pools.
Scenario 2: The HA assigns an IP address to the MN from one of its locally configured dynamic pools.
Scenario 1: AAA server and PDSN/FA Allocate IP Address
The following figure and table display and describe a call flow in which the MN receives its IP address from the AAA
server and PDSN/FA.