Polycom 1725-11530-310 ユーザーズマニュアル

Administrator’s Guide SoundPoint IP / SoundStation IP 

4 - 68

• An expires parameter is defined to indicate the lifespan of the URL itself, 

or, assuming that the URL is permanent, the time span for which the 

content is expected to have relevance to the call with which it is associated. 

If the parameter is absent or invalid, this will be interpreted to mean that 

the content or the URL itself will be persistent in nature. A value, if it is 

present, will indicate the lifespan of the content in seconds (zero has 

special significance—see example below). When the lifespan expires, the 

phone will remove both the indication of the URL and the ability of the 

user to retrieve it.
For example:

Access-URL: 

<http://server.polycom.com/content23456.xhtml>;expires=60

If the server wishes to invalidate a previous URL, it can send a new header 

(through UPDATE) with expires=0. The expires parameter is ignored when 

determining whether to spontaneously retrieve the web content unless 

expires=0.

• A mode parameter is defined to indicate whether the web content should 

be displayed spontaneously or retrieved on-demand. Two values are 

allowed: active and passive. If the parameter is absent or invalid, this will 

be interpreted the same as passive, meaning that the web content will be 

retrievable on-demand but will not be spontaneously displayed. If the 

value is set to active, the web content will be spontaneously displayed, 

subject to the rules discussed under Active Mode in 

Web Content 

Retrieval

 on page 

4-66

.

For example:

Access-URL: 

<http://server.polycom.com/content23456.xhtml>;expires=60;mode

=passive

In this case, the phone will indicate in the call appearance user interface 

that web content is available for a period of 60 seconds and will retrieve 

the web content at the request of the user for a period of up to 60 seconds 

but the phone will not spontaneously switch to the microbrowser 

application and download the content.

Starting with SIP 2.1.0, failover redundancy can only be utilized when the 

configured IP server hostname resolves (through SRV or A record) to multiple 

IP addresses. Unfortunately, some customer’s are unable to configure the DNS 

to take advantage of failover redundancy.
The solution in SIP 3.1 is to provide the ability to statically configure a set of 

DNS NAPTR SRV and/or A records into the phone.