The SRV record has a TXT record associated with it that provides additional information about the DiscoveryUrl. The format of this record is a sequence of strings prefixed by a length. This specifications adopts the key-value syntax for TXT records described in DNS-SD.
Table 69 defines the syntax for strings that may in the TXT record.
Table 69 – DNS TXT Record String Format
|path=/<path>||Specifies the text that appears after the port number when constructing a URL. This text always starts with a forward slash (/).|
|caps=<capability1>,<capability2>||Specifies the capabilities supported by the Server.
These are short (<=8 character) strings which are published by the OPC Foundation (see Annex D). The number of capabilities supported by a Server should be less than 10.
The MulticastExtension shall convert DiscoveryUrls to and from these SRV records.