A MountPt (or a “mount point” when the term is fully spelled out) is the specification by which an NTRIP client connects to a data stream on an NTRIP Caster. Often the term refers to just the unique string name, and most NTRIP clients think in terms of that string.
Very Important to remember: MountPt strings that determine what data stream to use in the Caster Table are ALWAYS case sensitive. They are always one word. They do not have leading or trailing spaces, nor do they have odd characters (!@#$%^&*();:'”,etc.) They are always a unique string in the table. They tend to start with a letter.
For example: If a user entered a “close” mountPt in his NTRIP Client software (say one that varies only by the capitalization), then SNIP will warn you the owner/operator about it on the console. But the end user will simply see a disconnect and the current caster table returned.
Hint: You can always take a quick look at what any caster table looks like by pointing your favorite browser to it. That is a good way to confirm that what you think might be there really is.
Each “full” mountPt consists of several distinctive parts and is commonly expressed as a string. SNIP uses a common format style shared by many tools to display this data. These strings appear in log reports and other places. The article describes how to read these strings. The term mountPt refers to either the unique Caster table entry or the full specification, depending on the context of us.
A mountPt string consists of up to five separate parts,
separated by four single character delimiters [ ; @ ; / ]
UserName : Password @ casterURL : Port / mountPt
The user portion is optional (it may be absent) and it may be encoded in a Base64 format (in which case the first “:” is missing). In most SNIP reports, an encoded user and password are shown as XX:XX to protect privacy.
As an example, if you wished to connect to a caster at 12.34.56.78 operating at port 8080 and a mount point called “test,” then the examples below are all valid mountPt strings:
- @12.34.56.78:8080/test
- :@12.34.56.78:8080/test
- user:password@12.34.56.78:8080/test
- dXNlcjpwYXNzd29yZA==@12.34.56.78:8080/test
Common Variations
- Some Casters use direct IP values like the above digits, while others use registered domain names like ntrip.xxx.org.
- Most Casters use the default port number of 2101, but any valid port number can be used.
- Some Casters require a user and password, while others do not (or will ignore one if it is provided).
- Spaces are not allowed in the examples above, and except for the domain name, all text is case sensitive.
Aside: SNIP employs some proprietary logic to ensure that every mountPt name is always unique. This is not often a problem unless you connect to the same remote caster mountPt. [In fact we and other researchers often do that as a side effect of system cross testing.] When a conflict is detected, an alias mountPt name with a unit number (_02, _03. etc.) is appended. This name is then automatically used in the caster tables and elsewhere so the user need not make any changes.