Cisco Cisco Packet Data Interworking Function (PDIF) Guida Alla Risoluzione Dei Problemi
IP Pool Sharing Protocol
▀ How IPSP Works
▄ Cisco ASR 5000 Series Enhanced Feature Configuration Guide
OL-22982-01
How IPSP Works
IPSP operation requires special configuration in both the primary and secondary HAs. As mentioned previously, both
HAs must have identical configurations. This allows the secondary HA to process sessions identically to the primary
when the primary is taken offline for upgrade.
HAs must have identical configurations. This allows the secondary HA to process sessions identically to the primary
when the primary is taken offline for upgrade.
Configuration must also be performed on the AAA server. Whereas subscriber profiles on the AAA server originally
directed sessions to the primary HA, prior to using IPSP, subscriber profiles must be re-configured to direct sessions to
the secondary HA.
directed sessions to the primary HA, prior to using IPSP, subscriber profiles must be re-configured to direct sessions to
the secondary HA.
There are two scenarios in which IPSP takes effect:
New sessions: Once IPSP is configured, new sessions are directed to a secondary HA (HA2) allowing the
primary HA to go through a software upgrade without degrading network capacity. The secondary HA requests
addresses from the primary HA‘s (HA1) pools as needed. As the addresses are allocated, they are busied out on
the primary HA. This procedure is displayed below.
addresses from the primary HA‘s (HA1) pools as needed. As the addresses are allocated, they are busied out on
the primary HA. This procedure is displayed below.
Session handoffs: Once IPSP is configured, sessions originally registered with the primary HA (HA1) are re-
registered with the secondary HA (HA2). To ensure the session is assigned the same IP address, the secondary
HA requests the address from the primary HA. The primary HA verifies the binding and releases it to the
secondary HA which, in turn, re-assigns it to the session. As the addresses are allocated, they are busied out on
the primary HA. This procedure is displayed below.
HA requests the address from the primary HA. The primary HA verifies the binding and releases it to the
secondary HA which, in turn, re-assigns it to the session. As the addresses are allocated, they are busied out on
the primary HA. This procedure is displayed below.
IPSP Operation for New Sessions
The following figure and text describe how new sessions are handled when IPSP is enabled.