Using Http Digest Authentication; Without Authentication; Call Forwarding To Pstn Gateway - Linksys SPA1001 Administrator User Manual

Call Scenarios
If the PSTN Line is busy (off-hook, ringing, or PSTN line not connected) when the VoIP caller calls, the
SPA3102 replies with 503. If the PIN number is invalid or entered after the VoIP call leg is connected,
the SPA3102 plays the reorder tone to the VoIP caller and eventually ends the call when the reorder tone
times out.
Note If <VoIP Caller ID Pattern> is specified and the VoIP caller ID does not match any of the given patterns,
the SPA3102 rejects the call with a 403. This rule applies regardless of the authentication method, even
when the source IP address of the INVITE request is in the <VoIP Access List>.

Using HTTP Digest Authentication

The same scenario can be implemented with HTTP digest authentication when the calling device
supports the configuration of a auth-ID and password to access the SPA3102 PSTN gateway. When the
VoIP caller calls the PSTN Line, the SPA3102 challenges the INVITE request with a 401 response. The
calling device should then provide the correct credentials in a subsequent retry of the INVITE, computed
with the auth-ID and password using MD5.
If the credentials are correct, the target number specified in the user-id field of the INVITE Request-URI
is processed by the dial plan corresponding to the VoIP user (assuming the dial plan choice is not 0).
The final number is then auto-dialed by the SPA3102.
If the credentials are incorrect, the SPA3102 challenges the INVITE again. If the auth-ID does not exist
in the SPA3102 configuration, the SPA3102 replies 403 to the INVITE. If the target number is invalid
according to the corresponding dial plan, the SPA3102 also replies 403 to the INVITE. Again, if the
PSTN Line is busy at the time of the call, the SPA3102 replies 503.
Note HTTP Digest Authentication is one way to perform one-stage dialing of a VoIP-To-PSTN call. The other
way is with no authentication require. However, if the target number is not specified in the Request-URI
or the number matches the account user-id of the PSTN Line, the call reverts to two-stage dialing.

Without Authentication

This scenario can also be implemented without authentication, using one-stage or two-stage dialing, as
in the HTTP Authentication case. The default VoIP caller dial plan is used in this scenario.
Authentication is performed when the method is none or when the source IP address of the inbound
INVITE matches one of the <VoIP Access List> patterns.

Call Forwarding to PSTN Gateway

This section describes a number of scenarios that forward calls to the PSTN gateway. It includes the
following topics:
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Linksys ATA Administrator Guide
4-10
Forward-On-No-Answer to the PSTN Gateway, page 4-11
Forward-All to the PSTN gateway, page 4-11
Forward to a Particular PSTN Number, page 4-11
Forward-On-Busy to PSTN Gateway or Number, page 4-11
Forward-Selective to PSTN Gateway or Number, page 4-11
Chapter 4 Configuring the PSTN Gateway (FXO)
Document Version 3.1