> ## Documentation Index
> Fetch the complete documentation index at: https://docs.megaport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshooting an MCR Routing Issue

> This help topic describes the troubleshooting steps and actions to take when a MCR is experiencing a routing issue.

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When Megaport Cloud Router (MCR) is experiencing a routing issue, step through these troubleshooting actions.

<Video url="https://youtu.be/XSNm5q3d3n0" text="How to Check the Network Latency" duration="1:23" description="This video shows how to check latency between Megaport points of presence and compare latency values across the Megaport network." />

## Troubleshooting actions

| **Action**                                                                                            | **Steps**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| :---------------------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Perform a <Gloss term="ping" anchor="ping" /> test between the source and destination**             | A **ping** test transmits data packets to a specific IP address and either confirms or denies connectivity between IP-networked devices. In the case of confirmation, a **ping** test shows the latency (the response time) of the connection. Provide the IP address and the subnet mask of services on the Megaport end used for the **ping** test.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| **Perform a <Gloss term="Traceroute" anchor="traceroute" /> test between the source and destination** | **Traceroute** testing can help to determine if a destination is reachable. **Traceroute** sends a sequence of <Gloss term="UDP" anchor="udp" /> packets between two points and shows you the route the packets take. **Traceroute** also measures the transit delays of packets across an IP network.<br />From the host that is originating traffic (A-End), start the **traceroute** to the destination host. Then run the **traceroute** from the destination host (B-End) to the origin host. Commands and flags might differ by device.<br /><br />**Analyze the results**<ol><li>Look for asymmetric routing. If the traffic is not taking the same path, there might be asymmetric routing somewhere in the network.</li> <li> Are there any places in the **traceroute** where the response time has increased markedly? If so, are those delays within your network?</li><li>Are there any firewalls or access list rules prohibiting traffic from reaching its destination?</li></ol> |
| **Verify routing configurations and routing tables**                                                  | <ol><li>Confirm both Layer 2 and Layer 3 configurations.</li><li>Review metrics, route filters, firewalls, and traffic shaping.</li><li> Verify the routing table (Layer 3) and confirm whether the prefix in question is reachable and on the expected routing path to Megaport.</li><li>Confirm that the gateway (the device facing the MCR) is advertising the required prefix if a route filter is in place.</li><li>Confirm the MCR routing table: [Viewing Traffic Routing Through MCR Looking Glass](/mcr/mcr-looking-glass).</li></ol>                                                                                                                                                                                                                                                                                                                                                                                                                                                   |

## Ping and traceroute

Megaport provides standard network diagnostic tools, such as ping and traceroute, directly from an MCR.

You can run diagnostic requests via the Megaport Portal or the Megaport API. After the tests are complete, the real-time results are retrieved and displayed in the Portal.

<Note>
  * Diagnostic requests (ping or traceroute) are initiated against a specified MCR.
  * The destination must be a valid IPv4 or IPv6 address.
  * The source must be a valid IPv4 or IPv6 address that is configured on the MCR interface.
  * You cannot cancel a running diagnostic request. The request must complete or naturally time out, then return the result before the next request will run.
</Note>

**To run a ping test**

Ping is available only on MCR with at least one active VXC connection.

1. Log in to the <Link href="https://portal.megaport.com">Megaport Portal</Link> and choose **Services**.

2. Click the Service Diagnostics icon or the Looking Glass icon.
   <Image src="/images/troubleshooting/mcr/service-diagnostics-looking-glass-icons.png" alt="Service diagnostics icon" shadow={true} width={980} />

3. Click the **Ping** tab.
   <Image src="/images/troubleshooting/mcr/ping.png" alt="Ping tab" shadow={true} width={400} />

4. Type the destination IP into the **Destination IP** field, then click **Run Ping**.\
   Latency results are returned.

   <Image src="/images/troubleshooting/mcr/ping-output.png" alt="Ping output" shadow={true} width={400} />

**To run a traceroute test**

Traceroute is available only on MCR with at least one active VXC connection.

1. Log in to the <Link href="https://portal.megaport.com">Megaport Portal</Link> and choose **Services**.

2. Click the Service Diagnostics icon or the Looking Glass icon.
   <Image src="/images/troubleshooting/mcr/service-diagnostics-looking-glass-icons.png" alt="Service diagnostics icon" shadow={true} width={980} />

3. Click the **Traceroute** tab.
   <Image src="/images/troubleshooting/mcr/traceroute.png" alt="Traceroute tab" shadow={true} width={400} />

4. Type the destination IP into the **Destination IP** field, then click **Run Traceroute**.\
   Packet routing and transit delay results are returned.

   <Image src="/images/troubleshooting/mcr/traceroute-output.png" alt="Traceroute output" shadow={true} width={400} />

### Ping and traceroute specifications

Ping and traceroute tests from an MCR are subject to certain limits and specifications. For more information, see  [Megaport Cloud Router (MCR)](/limits-quotas#mcr).

## Next steps

If the troubleshooting actions do not resolve your issue, contact support. Before contacting support for assistance, collect the following information.

* **Troubleshooting results** -- Provide all troubleshooting steps taken in detail.

* **General details** -- The date, time, and time zone in which the issue started.

* **Loopback details** -- If you placed loopbacks, note their location and direction.

* **Interface and BGP configurations on the customer device/Cloud Service Provider side**
  * Provide the interface settings, including the VLAN number.
  * Provide any static routes and routing protocol configurations (EIGRP/OSPF/BGP).
  * Provide the BGP ASN.
  * Provide all firewall rules and ACL configurations for the data flow experiencing the issue.

* **Source and destination IP addresses**
  * Provide the **IP packet** field containing the IP address of the originating device.
  * Provide the **IP packet** field containing the IP address of the destination device.

* **High-level network diagram** -- Understanding how your network design is implemented and the connection into the Megaport network helps identify additional focus areas within the troubleshooting process. Provide a network diagram that includes all devices in the path; note each device’s involved IP addresses and VLANs.

* **Ping test results** -- Provide the output of each **ping** test performed on the service. Provide output tests for all services related to different products (Port, VXC, MCR).

* **Traceroute test results** -- Provide **traceroute** results indicating which side of the connection initiated the test and which side was the destination. We recommend using the A-End and B-End information from your VXC.

<Note>
  For more information about when a field service technician is needed onsite at the data center, see [Customer Field Services](/finance/customer-field-services).
</Note>