| period to be used for the session. |
Session timers | This is the minimum session timer expiration period that FLX will |
minimum | accept when negotiating the expiration period with the remote |
expiration period | phone. It is measured in seconds; the default is 90. |
Require reliable | Select this option to implement reliable SIP provisional responses. |
SIP provisional | By default the setting is unchecked. SIP is a |
response | of protocol with two types of responses: provisional and final. Final |
| responses are sent reliably, using an ACK to ensure receipt. |
| Provisional responses by default are not sent reliably and do not |
| require an ACK; however, in some cases, such as for PSTN |
| interoperability support, reliability of provisional types of responses |
| is needed. Choose this option to add the PRACK (provisional ACK) |
| message support for reliability. |
Enable SIP | This option may be used when the phone is behind a symmetric |
traversal behind | NAT (Network Address Translation). When enabled, FLX will keep |
symmetric NAT | track of the public IP address from the response of the REGISTER |
| request. If it detects that the address has changed, it will unregister |
| the current Contact, update the Contact with the transport address |
| obtained from the Via header, and register a new Contact to the SIP |
| registrar. This option will also update the public name of the UDP |
| transport if STUN is configured. |
Suppress SIP | When transferring a SIP call, the SIP REFER process automatically |
event | establishes a temporary event subscription to notify the party |
subscription | initiating the transfer about the receiver’s status in handling the |
when transferring | REFER. In some cases these event subscriptions and notifications |
calls | are not needed, such as when forking is not used. Enable this option |
| to suppress the automatic event subscriptions when transferring |
| calls. The option is disabled by default. |
Allow strict | By default, proxies specified on the SIP Registration page will be |
routing | configured as |
| (“;lr”) will be automatically appended to each proxy address when |
| the proxy is added to the SIP Route header. Older proxies may be |
| |
| (see IETF RFC 3261). Enable this option if you are using strict- |
| routing proxies. If this option is enabled and you are specifying one |
| or more |
| Outbound Proxy field, then you must manually add the “;lr” suffix to |
| each |
Minimize SIP | The SIP protocol specifies that header field names can be in the full |
message size | name form or in the abbreviated form. Abbreviated form is useful |
| when messages might be too large to be carried on the available |
| transport, for example when exceeding UDP’s Maximum |
| Transmission Unit (MTU). Enable this option to encode SIP headers |
| in their short forms to reduce size. By default, the option is not |
| enabled and SIP headers in outgoing messages will be encoded in |
| their full names. (See SIP protocol standard, IETF RFC 3261.) |
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