
Configuring SIP, SPCP, and NAT
SIP and Cisco IP Phones
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide
118
4
In the failover/recovery scenario, the phone remains registered to the primary
proxy, but makes and receives calls on the alternate proxy. The SPA IP phone re-
registers upon failover or recovery with "BT" configured in
Try Backup RSC
field
under the ”Response Status Code Handling” section of
SIP
tab. The ”Try Backup
RSC” parameter can be used to invoke failover upon receiving specified response
codes.
RFC3311 Support
The Cisco SPA525G or Cisco SPA525G2 support RFC-3311, the SIP UPDATE
Method.
Support for SIP NOTIFY XML-Service
The Cisco SPA300 Series and Cisco SPA500 Series IP phones support the SIP
NOTIFY XML-Service event. On receipt of a SIP NOTIFY message with an XML-
Service event, the IP phone challenges the NOTIFY with a 401 response if the
message does not contain correct credentials. The client must be furnish the
correct credentials using MD5 digest with the SIP account password for the
corresponding line of the IP phone.
The body of the message can contain the XML event Message. For example:
<CiscoIPPhoneExecute>
<ExecuteItem Priority="0" URL="http://xmlserver.com/event.xml"/>
</CiscoIPPhoneExecute>
Authentication:
challenge = MD5( MD5(A1) ":" nonce ":" nc-value ":" cnonce ":" qop-value
":" MD5(A2) )
where A1 = username ":" realm ":" passwd
and A2 = Method ":" digest-uri