 | Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |
The PIC failover procedure for the packet gateway assures service continuity in case of a service PIC failure. The packet gateway architecture provides both a 1:1 redundancy model and a 1:N redundancy model for service PICs.
In the 1:1 redundancy model, there is one primary service PIC and one secondary service PIC that acts as a backup. If the primary service PIC fails, the Routing Engine allocates the secondary service PIC, and the software switches over to the secondary service PIC. The PGCP process continues to provide the PGCP services as if the service PIC has restarted. All states and sessions are lost, but new calls are accepted. When the failed service PIC recovers, it does not take over from the redundant PIC.
In the 1:N redundancy model, you can define one PIC as the secondary of many primary PICs. In this model, after the secondary PIC becomes active, all other primary PICs are left without a secondary PIC. Even when the primary PIC recovers, it does not become a redundant PIC to all of the primary PICs. A recovered primary PIC can replace only the same secondary PIC that previously replaced it. This functionality means that administrative involvement is usually required after a failover event happens.
| Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |