Cisco SPA1112 Provisioning Manual page 41

In-House Preprovisioning and Provisioning Servers
Provisioning Server Setup
Provisioning Guide for Cisco SPA100 and SPA200 Series Analog Telephone Adapters
Voice over IP can co-exist with NAT only when some form of NAT traversal is
provided. Configure Simple Traversal of UDP through NAT (STUN). This option
requires that the user have (1) a dynamic external (public) IP address from your
service, (2) a computer running STUN server software, and (3) an edge device
with an asymmetric NAT mechanism.
HTTP Provisioning
The ATA behaves like a browser requesting web pages from a remote Internet site.
This provides a reliable means of reaching the provisioning server, even when a
customer router implements symmetric NAT or other protection mechanisms.
HTTP and HTTPS work more reliably than TFTP in remote deployments,
especially when the deployed units are connected behind residential firewalls or
NAT-enabled routers.
Basic HTTP-based provisioning relies on the HTTP GET method for retrieving
configuration profiles. Typically, a configuration file is created for each deployed
ATA, and these files are stored within a HTTP server directory. When the server
receives the GET request, it simply returns the file specified in the GET request
header.
Alternatively, the requested URL can invoke a CGI script (using the GET method).
The configuration profile is generated dynamically by querying a customer
database and producing the profile on-the-fly.
When CGI handles resync requests, the ATA can use the HTTP POST method to
request the resync configuration data. The device can be configured to convey
certain status and identification information to the server within the body of the
HTTP POST request. The server uses this information to generate a desired
response configuration profile, or store the status information for later analysis and
tracking.
As part of both GET and POST requests, the ATA automatically includes basic
identifying information in the request header, in the User-Agent field. This
information conveys the manufacturer, product name, current firmware version,
and product serial number of the device.
For example, the following example is the User-Agent request field from a SPA962:
User-Agent: cisco/SPA-962-2.0.5 (88012BA01234)
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