add some info about rule names and priority

Author: vhorne

articles/firewall/rule-processing.md

@@ -5,23 +5,25 @@ services: firewall
 author: vhorne
 ms.service: firewall
 ms.topic: article
-ms.date: 03/10/2020
+ms.date: 04/10/2020
 ms.author: victorh
 ---
 
 # Azure Firewall rule processing logic
-You can configure NAT rules, network rules, and applications rules on Azure Firewall. The rules are processed according to the rule type. 
+You can configure NAT rules, network rules, and applications rules on Azure Firewall. Rule collections are processed according to the rule type in priority order, lower numbers to higher numbers from 100 to 65,000. A rule collection name can have only letters, numbers, underscores, periods, or hyphens. It must begin with a letter or number, and end with a letter, number or underscore. The maximum name length is 80 characters.
+
+It's best to initially space your rule collection priority numbers in 100 increments (100, 200, 300, and so on) so you have room to add more rule collections if needed.
 
 > [!NOTE]
 > If you enable threat intelligence-based filtering, those rules are highest priority and are always processed first. Threat-intelligence filtering may deny traffic before any configured rules are processed. For more information, see [Azure Firewall threat intelligence-based filtering](threat-intel.md).
 
-## Outbound
+## Outbound connectivity
 
 ### Network rules and applications rules
 
 If you configure network rules and application rules, then network rules are applied in priority order before application rules. The rules are terminating. So if a match is found in a network rule, no other rules are processed.  If there is no network rule match, and if the protocol is HTTP, HTTPS, or MSSQL, then the packet is then evaluated by the application rules in priority order. If still no match is found, then the packet is evaluated against the [infrastructure rule collection](infrastructure-fqdns.md). If there is still no match, then the packet is denied by default.
 
-## Inbound
+## Inbound connectivity
 
 ### NAT rules