Troubleshooting an MCR Routing Issue

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

Troubleshooting actions

Action Steps
Perform a 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 traceroute test between the source and destination Traceroute testing can help to determine if a destination is reachable. Traceroute sends a sequence of User Datagram Protocol (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.
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.
Analyze the results:
  1. Look for asymmetric routing. If the traffic is not taking the same path, there might be asymmetric routing somewhere in the network.
  2. Are there any places in the traceroute where the response time has increased markedly? If so, are those delays within your network?
  3. Are there any firewalls or access list rules prohibiting traffic from reaching its destination?
Verify routing configurations and routing tables
  1. Confirm both Layer 2 and Layer 3 configurations.
  2. Review metrics, route filters, firewalls, and traffic shaping.
  3. Verify the routing table (Layer 3) and confirm whether the prefix in question is reachable and on the expected routing path to Megaport.
  4. Confirm that the gateway (the device facing the MCR) is advertising the required prefix if a route filter is in place.
  5. Confirm the MCR routing table: Viewing Traffic Routing Through MCR Looking Glass.

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.

Last update: