# Index-based namespace and namespace URI's in 8.1.X

**URL:** <https://forum.inductiveautomation.com/t/index-based-namespace-and-namespace-uris-in-8-1-x/62404>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [July 28, 2022, 11:00am UTC](https://forum.inductiveautomation.com/t/index-based-namespace-and-namespace-uris-in-8-1-x/62404 "2022-07-28T11:00:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![coffee732](https://avatars.discourse-cdn.com/v4/letter/c/b9e5f3/32.png) [@coffee732](https://forum.inductiveautomation.com/u/coffee732)\
**Post date:** [July 28, 2022, 11:00am UTC](https://forum.inductiveautomation.com/t/index-based-namespace-and-namespace-uris-in-8-1-x/62404/1 "2022-07-28T11:00:33Z")

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I’m looking at a project that was developed in 8.1.? where the OPC tag addresses use ‘nsu=urn:inductiveautomation:ignition:opcua:tags;s=’ in the OPC path.

Should this work, or has this been phased out / changed in a newer version of Ignition 8.1.X where only index-based namespace will work? ‘ns1;s=’?

When trying to read from these tags in the designer I get a configuration error:  
_Bad(“Bad\_NodeIdUnknown: The node id refers to a node that does not exist in the server address space.”)_

I’m trying to work out if I need to update all the OPC addresses, or if there is some additional configuration i’m not aware of?

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [July 28, 2022, 12:34pm UTC](https://forum.inductiveautomation.com/t/index-based-namespace-and-namespace-uris-in-8-1-x/62404/2 "2022-07-28T12:34:52Z")

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> [@coffee732](#):
>
> ‘ns1;s=’?

Is this a forum typo? (It should be `ns=1;s=`.) If not, that would be your problem. Note that namespace #1 is the default if omitted.

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [July 28, 2022, 12:37pm UTC](https://forum.inductiveautomation.com/t/index-based-namespace-and-namespace-uris-in-8-1-x/62404/3 "2022-07-28T12:37:14Z")

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What you’re seeing is a tag added to that gateway that came from the Exposed Tags feature. If it was from the _same_ gateway that was probably a mistake, but if it was from another gateway that’s probably okay.

When tags are brought in from the OPC Browser to the Tag Browser the the full namespace URI is used any time the index is 2+, regardless of the server.

In the Ignition OPC UA server the tags exposed by the Exposed Tags feature reside at namespace index 2.