Update ix.md (#24459)

ads/ix.md

@@ -14,37 +14,44 @@ See the License for the specific language governing permissions and
 limitations under the License.
 -->
 
-# Index Exchange
+# Index Exchange AMP RTC 
 
-Index supports Header Tag style bidding using DoubleClick as the ad server.
-
-## Example
-
-```html
-<amp-ad width="300" height="250"
-  type="ix"
-  data-ix-id="54321"
-  data-slot="/1234/example">
-</amp-ad>
-```
+Index Exchange (IX) supports [AMP Real Time Config (RTC)](https://github.com/ampproject/amphtml/blob/master/extensions/amp-a4a/rtc-publisher-implementation-guide.md) which allows Publishers to augment their ad requests with targeting information that is retrieved at runtime. This document provides instructions on adding IX as a vendor to AMP pages.  
 
 ## Configuration
+Each [amp-ad](https://amp.dev/documentation/components/amp-ad/) element that uses RTC must have the `rtc-config` attribute set with valid JSON. 
 
-For semantics of configuration, please contact your account manager at Index Exchange.
-
-If you use `remote.html` in your AMP pages, you must add `ix` into the array that outlines the list of acceptable types. For example, `['doubleclick']` should be changed to `['doubleclick', 'ix']`. If you do not use `remote.html`, this step is not required.
-
-Ad size is based on the `width` and `height` attributes of the `amp-ad` tag by default. Both width and height override attributes (`data-override-width` and `data-override-height`) and multi-size ads (via `data-multi-size`) are supported.
+### Example: RTC Specification on an amp-ad
 
-### Required parameters
-
-- `data-ix-id`
-- `data-slot`
+```
+<!-- Note: Default timeout is 1000ms -->
+<amp-ad width="320" height="50" type="doubleclick"
+        data-slot="/1234/pos"
+        rtc-config='{
+            "vendors": {
+                "IndexExchange": {"SITE_ID": "123456"},
+            },
+            "timeoutMillis": 1000}'>
+</amp-ad>
+```
+The value of `rtc-config` must conform to the following specification:
+```
+{
+            "vendors": {
+                "IndexExchange": {"SITE_ID": "123456"},
+            },
+            "timeoutMillis": 1000'
+  }
+```
+- `<amp-ad>`: Required. Index Exchange `<amp-ad>` tags require the `width`, `height`, and `type="doubleclick"` parameters. Note that Index Exchange leverages AMP through Google Ad Manager (GAM, formerly Doubleclick for Publishers).
+- `data-slot`: Required. Data attributes to serve ads.
+- `rtc-config`: JSON configuration data which handles the communication with AMP RTC.
+   - `vendors` : Required object. The key is `IndexExchange` and the value is the `SITE_ID`.</br>
+**Note:** Refer to the materials provided by your account team for your specific **SITE_ID** details. We recommend one **SITE_ID** per domain, per unique slot and size. To use more than one SITE_ID, contact your IX Representative.
+   - `timeoutMillis`: Optional integer. Defines the timeout in milliseconds for each individual RTC callout. The configured timeout must be greater than 0 and less than 1000ms. If omitted, the timeout value defaults to 1000ms.
 
-### Optional parameters
+Additional parameters including JSON are passed through in the resulting call to DFP. For details refer to the [Doubleclick documentation](https://github.com/ampproject/amphtml/blob/master/extensions/amp-ad-network-doubleclick-impl/amp-ad-network-doubleclick-impl-internal.md).
 
-- `data-ix-slot`
-- `data-ix-timeout`
+To learn about the required Google Ad Manager (GAM) configuration, refer to [Index Exchange Knowledge Base](https://kb.indexexchange.com/Mobile/AMP_Integration.htm).
 
-Additional parameters including `json` will be passed through in the resulting call to DFP. For details please see the [Doubleclick documentation](https://github.com/ampproject/amphtml/blob/master/ads/google/doubleclick.md).