added limits, changed aad reference, up behavior

Author: george-guirguis

articles/event-grid/includes/limits.md

@@ -32,6 +32,7 @@ The following limits apply to MQTT in Azure Event Grid namespace resource.
 |----------------------------------------------|-----------------------------------------------------------------------------------|
 | MQTT connections per namespace               | 10,000 per TU                                                                     |
 | Sessions per namespace                       | 10,000 per TU                                                                     |
+| Session Expiry Interval                      | 8 hours, [configurable on the namesapce](../mqtt-support.md##maximum-session-expiry-interval-configuration)|
 | Inbound MQTT publish requests per namespace  | 1,000 messages per second                                                         |
 | Inbound MQTT bandwidth per namespace         | 1 MB per second per TU                                                            |
 | Inbound MQTT publish requests per connection | 100 messages per second                                                           |
@@ -41,20 +42,22 @@ The following limits apply to MQTT in Azure Event Grid namespace resource.
 | Outbound MQTT publish requests per connection| 100 messages per second                                                           |
 | Outbound MQTT bandwidth per connection       | 1 MB per second                                                                   |
 | Max message size                             | 512 KB                                                                            |
+| Segments per topic/ topic filter             | 8                                                                                 |
 | Topic size                                   | 256 B                                                                             |
-| Segments per topic filter                    | 8                                                                                 |
+| MQTTv5 response topic                        | 256 B                                                                             |
 | MQTTv5 topic aliases                         | 10 per connection                                                                 |
 | MQTTv5 user properties size                  | 8 KB                                                                              |
-| MQTTv5 content type size                     | 256 Bytes                                                                         |
-| MQTTv5 correlation data size                 | 8 KB                                                                              |
+| MQTTv5 content type size                     | 256 B                                                                             |
+| MQTTv5 correlation data size                 | 256 B                                                                             |
 | Connect requests                             | 200 requests per second per TU                                                    |
 | MQTTv5 authentication data size              | 8 KB                                                                              |
 | Maximum keep-alive interval                  | 1160                                                                              |
-| Subscribe and unsubscribe requests           | 200 requests per second per TU                                                    |
 | Topic filters per MQTT SUBSCRIBE packet      | 10                                                                                |
-| Subscriptions per MQTT client session        | 50                                                                                |
-| Subscriptions per namespace                  | 2 million                                                                         |
-| Subscriptions per MQTT topic                 | Unlimited                                                                         |
+| Subscribe and unsubscribe requests per namespace | 200 requests per second                                                       |
+| Subscribe and unsubscribe requests per connection | 5 requests per second                                                        |
+| Subscriptions per MQTT connection            | 50                                                                                |
+| Subscriptions per namespace                  | 1 million                                                                         |
+| Subscriptions per MQTT topic                 | Unlimited, as long as they don't exceed the limit for subscriptions per namespace or connection|
 | Registered client resources                  | 10,000 clients per TU                                                             |
 | CA certificates                              | 2                                                                                 |
 | Client groups                                | 10                                                                                |
@@ -63,8 +66,6 @@ The following limits apply to MQTT in Azure Event Grid namespace resource.
 | Permission bindings                          | 100                                                                               |
 
 
-
-
 ## Events limits in namespace
 
 The following limits apply to events in Azure Event Grid namespace resource.

articles/event-grid/mqtt-overview.md

@@ -73,7 +73,7 @@ IoT applications are software designed to interact with and process data from Io
 
 ### Client authentication
 
-Event Grid has a client registry that stores information about the clients permitted to connect to it. Before a client can connect, there must be an entry for that client in the client registry. As a client connects to MQTT broker, it needs to authenticate with MQTT broker based on credentials stored in the identity registry. MQTT broker supports X.509 certificate authentication that is the industry authentication standard in IoT devices and [Microsoft Entra](mqtt-client-azure-ad-token-and-rbac.md) that is Azure's authentication standard for applications.[Learn more about MQTT client authentication.](mqtt-client-authentication.md) 
+Event Grid has a client registry that stores information about the clients permitted to connect to it. Before a client can connect, there must be an entry for that client in the client registry. As a client connects to MQTT broker, it needs to authenticate with MQTT broker based on credentials stored in the identity registry. MQTT broker supports X.509 certificate authentication that is the industry authentication standard in IoT devices and [Microsoft Entra ID (formerly Azure Active Directory)](mqtt-client-azure-ad-token-and-rbac.md) that is Azure's authentication standard for applications.[Learn more about MQTT client authentication.](mqtt-client-authentication.md) 
 
 ### Access control
 

articles/event-grid/mqtt-support.md

@@ -133,9 +133,9 @@ MQTT v5 currently differs from the [MQTT v5 Specification](https://docs.oasis-op
 - Message ordering isn't guaranteed.
 - Subscription Identifiers aren't supported.
 - Assigned Client Identifiers aren't supported yet.
-- The server responds to a CONNECT request with either Authentication Method or Authentication Data with a CONNACK with code 0x8C (Bad authentication method) or 0x87 (Not Authorized) respectively.
 - Topic Alias Maximum is 10. The server doesn't assign any topic aliases for outgoing messages at this time. Clients can assign and use topic aliases within set limit.
 - CONNACK doesn't return Response Information property even if the CONNECT request contains Request Response Information property.
+- User Properties on CONNECT, SUBSCRIBE, DISCONNECT, PUBACK, AUTH packets are not used by the service so they're not supported. If any of these requests include user properties, the request will fail.
 - If the server receives a PUBACK from a client with non-success response code, the connection is terminated.
 - Keep Alive Maximum is 1160 seconds.
 

articles/event-grid/overview.md

@@ -51,7 +51,7 @@ Event Grid offers a rich mixture of features. These features include:
 - **[Built-in cloud integration](mqtt-routing.md)** - route your MQTT messages to Azure services or custom webhooks for further processing.
 - **Flexible and fine-grained [access control model](mqtt-access-control.md)** - group clients and topic to simplify access control management, and use the variable support in topic templates for a fine-grained access control.
 - **X.509 certificate [authentication](mqtt-client-authentication.md)** - authenticate your devices using the IoT industry's standard mechanism for authentication.
-- **[AAD authentication](mqtt-client-azure-ad-token-and-rbac.md)** - authenticate your applications using the Azure's standard mechanism for authentication.
+- **[Microsoft Entra ID (formerly Azure Active Directory) authentication](mqtt-client-azure-ad-token-and-rbac.md)** - authenticate your applications using the Azure's standard mechanism for authentication.
 - **TLS 1.2 and TLS 1.3 support** - secure your client communication using robust encryption protocols.
 - **Multi-session support** - connect your applications with multiple active sessions to ensure reliability and scalability.
 - **MQTT over WebSockets** - enable connectivity for clients in firewall-restricted environments.