Merge pull request #262961 from duongau/ratelimitingprovider

ExpressRoute - About rating limiting for ExpressRoute circuits with service provider ports (new article)

Author: v-shils

articles/expressroute/TOC.yml

@@ -89,6 +89,8 @@
     href: expressroute-bfd.md
   - name: QoS requirements
     href: expressroute-qos.md
+  - name: Rate limit for service provider ports
+    href: provider-rate-limit.md
   - name: Routing Microsoft 365 traffic over ExpressRoute 
     href: using-expressroute-for-microsoft365.md
   - name: Routing Microsoft PSTN traffic over ExpressRoute

articles/expressroute/media/provider-rate-limit/circuit.png

@@ -0,0 +1,45 @@
+---
+title: About rating limiting for ExpressRoute circuits over service provider ports
+titleSuffix: Azure ExpressRoute
+description: This document discusses how rate limiting works for ExpressRoute circuits over service provider ports. You'll also learn how to monitor the throughput and traffic drop due to rate limiting.
+services: expressroute
+author: duongau
+ms.service: expressroute
+ms.topic: conceptual
+ms.date: 01/12/2024
+ms.author: duau
+---
+
+# About rating limiting for ExpressRoute circuits over service provider ports
+
+This article discusses how rate limiting works for ExpressRoute circuits created over service provider ports. You'll also learn how to monitor the throughput and traffic drop due to rate limiting.
+
+## How does rate limiting work over an ExpressRoute circuit?
+
+An ExpressRoute circuit consists of two links that connects the Customer/Provider edge to the Microsoft Enterprise Edge (MSEE) routers. If your circuit bandwidth is 1 Gbps and you distribute your traffic evenly across both links, you can achieve a maximum throughput of 2 Gbps (two links * 1 Gbps). Rate limiting restricts your throughput to the configured bandwidth if you exceed it on either link. The ExpressRoute circuit SLA is only guaranteed for the bandwidth that you configured. For example, if you purchased a 1-Gbps circuit, you're SLA is for a maximum throughput of 1 Gbps.
+
+:::image type="content" source="./media/provider-rate-limit/circuit.png" alt-text="Diagram of rate limiting on an ExpressRoute circuit over provider ports.":::
+
+## How can I determine what my circuit throughput is?
+
+You can monitor the ingress and egress throughput of your ExpressRoute circuit for both links through the Azure portal using ExpressRoute circuit metrics. For ingress, select `BitsInPerSecond` and for egress, select `BitsOutPerSecond`.  The following screenshot shows the ExpressRoute circuit metrics for ingress and egress throughput.
+
+:::image type="content" source="./media/provider-rate-limit/throughput-metrics.png" alt-text="Screenshot of the throughput per seconds metrics for an ExpressRoute Direct circuit.":::
+
+## How can I identify if traffic is being dropped due to rate limiting?
+
+You can monitor the traffic that is being dropped due to rate limiting through the Azure portal using the ExpressRoute circuit QOS metrics. For ingress, select `DroppedInBitsPerSecond` and for egress, select `DroppedOutBitsPerSecond`. The following screenshot shows the ExpressRoute circuit QOS metrics for ingress and egress throughput.
+
+:::image type="content" source="./media/provider-rate-limit/drop-bits-metric.png" alt-text="Screenshot of the drop bits per seconds metrics for an ExpressRoute Direct circuit.":::
+
+## How can I increase my circuit bandwidth?
+
+You can seamlessly increase your circuit bandwidth through the Azure portal. For more information, see [About upgrading ExpressRoute circuit bandwidth](about-upgrade-circuit-bandwidth.md).
+
+## What are the causes of traffic drop when the throughput is below the configured bandwidth?
+
+ExpressRoute circuit throughput is monitored at an aggregate level of every few minutes. While the rate-limiting is enforced at a granular level in milliseconds. Therefore, occasional traffic bursts exceeding the configured bandwidth might not get detected by the throughput monitoring. However, the rate-limiting is still be enforced and traffic gets dropped.
+
+## Next steps
+
+For more frequently asked questions, see [ExpressRoute FAQ](expressroute-faqs.md).