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1. For outbound calling, you cannot have more than one ITSP account per ITSP domain. However, you can have multiple accounts for a given ITSP for inbound calling, assuming that your ITSP allows multiple accounts to be registered from the same IP address and port.
2. No end to end encryption. Since sipXbridge is relaying media it breaks end to end encryption.
3. To simplify the design, media is always relayed through sipxrelay when a call passes through sipXbridge. The bridge avoids hairpinning the media path however, so there is only one relay for a given end to end call and the same relay is used throughout the call.

Tricks

By default sipxbridge/sipxrelay will ALWAYS anchor media.

There is a flag which is not supported via sipxconfig ( i.e. experimental flag ) which will allow you to remove the media anchor for forwarded calls.

It is called <always-relay-media> Look in the sipxbridge.xsd file for a description. By default that flag is true and it is hidden. You can set it to false by editing sipxbridge.xml and if you do so, then for hairpinned forwarded or blind transferred calls, the media relay will be removed from the media path AFTER transfer.

HA Configuration

For HA Configuration each node of the HA system must have media relay ports that do not overlap with the other server. Otherwise media relaying will not work correctly
If you have enabled SIP trunking on more than one server, ITSP account configurations should not interfere with each other.

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