> # Guidelines and Limitations

> ## Call Home Database Merger Guidelines

> When merging two Call Home databases, follow these guidelines:

> - Be aware that the merged database contains the following information:
> - A superset of all the destination profiles from the dominant and subordinate switches that take part in the merge protocol.
> - The e-mail addresses and alert groups for the destination profiles.
> - Other configuration information (for example, message throttling, periodic inventory) from the switch that existed in the dominant switch before the merge.
> - Verify that two destination profiles do not have the same name (even if they have different configuration information) on the subordinate and dominant switches. If they do contain the same name, the merge operation will fail. You must then modify or delete the conflicting destination profile on the required switch.

> See the "CFS Merge Support" topic for detailed concepts.

> ## Call Home Configuration Guidelines

> When configuring Call Home, follow these guidelines:

> - An e-mail server and at least one destination profile (predefined or user-defined) must be configured. The destination profile(s) used depends on whether the receiving entity is a pager, e-mail, or automated service such as Cisco Smart Call Home.
> - Switches can forward events (SNMP traps/informs) up to 10 destinations.
> - The contact name (SNMP server contact), phone, and street address information must be configured before Call Home is enabled. This configuration is required to determine the origin of messages received.
> - The Cisco MDS 9000 Family switch and the Cisco Nexus 5000 Series switch must have IP connectivity to an e-mail server.
> - If Cisco Smart Call Home is used, an active service contract must cover the device being configured.

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