Alternative Routing Upon Sip 3Xx With Multiple Contacts; Pstn Fallback - AudioCodes Mediant 800 User Manual

CHAPTER 25 Routing
2. Enable alternative routing based on SIP responses:
a. Open the Proxy & Registration page (Setup menu > Signaling & Media tab > SIP
Definitions folder > Proxy & Registration).
b. From the 'Redundant Routing Mode' drop-down list, select one of the following:
● Routing Table: Tel-to-IP Routing table is used for alternative routing.
● Proxy: Proxy Set redundancy feature is used for alternative routing.
3. If you are using the Tel-to-IP Routing table, configure alternative routing rules with identical call
matching characteristics, but different IP destinations. If you are using the Proxy Set,
configure redundant proxies.

Alternative Routing upon SIP 3xx with Multiple Contacts

You can configure how the device handles received SIP 3xx responses that contain multiple
alternative contacts. The 3xx response indicates that the original destination is unavailable (e.g.,
301 Moved Permanently – user cannot be found) and that the call can be redirected to alternative
destinations specified in the SIP Contact headers.
Configured by the '3xx Use Alt Route Reasons' parameter, the device can handle the receipt of 3xx
responses using one of the following methods:
■ The device tries each contact sequentially, listed in the Contact headers, until a successful
destination is found. If a contact responds with a SIP 486 or 600, the device does not try to
redirect the call to the next contact and drops the call.
■ The device tries each contact sequentially, listed in the Contact headers. If a SIP 6xx Global
Failure response is received during this process (e.g., 600 Busy Everywhere), the device does
not try to redirect the call to the next contact and drops the call.
■ The device redirects the call to the first contact listed in the Contact header. If the contact
responds with a SIP response that is configured in the Reasons for Tel-to-IP Alternative
Routing table (see
the call to the next contact, and so on. If a contact responds with a response that is not
configured in the table, the device does not try to redirect the call to the next contact and drops
the call.
➢
To configure handling of SIP 3xx responses with multiple contacts:
1. Open the Gateway Advanced Settings page (Setup menu > Signaling & Media tab >
Gateway folder > Gateway Advanced Settings).
2. From the '3xx Use Alt Route Reasons' drop-down list, select the required handling.
3. Click Apply.
If a SIP 401 or 407 response is received from a contact, the device does not try to
redirect the call to the next contact. Instead, the device continues with the regular
authentication process, as indicated by these response types.

PSTN Fallback

The PSTN Fallback feature enables the device to re-route a Tel-to-IP call to the legacy PSTN using
one of its trunks if the IP destination is unavailable. For example, if poor voice quality is detected
over the IP network, the device attempts to re-route the call to the PSTN.
Alternative Routing Based on SIP
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Mediant 800 Gateway & E-SBC | User's Manual
Responses), the device tries to redirect