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Configuring an MCR

This topic describes how to edit a Megaport Cloud Router (MCR) and Virtual Cross Connect (VXC) configuration. Before you begin, you need to create an MCR and configure a VXC, as described in Creating an MCR and Creating an MCR VXC.

Editing an MCR

To edit an MCR

  1. Choose Networking > Services.
  2. Select an MCR or use the search filter to locate and select an MCR.

  3. Click the Configuration tab. Edit MCR

  4. Click Edit.

  5. You can edit any field on the MCR Configuration tab. Note that the MCR rate limit is fixed for the duration of the service, so it doesn’t appear on this tab.

    • The Initial BGP State lets you select whether newly created BGP connections are enabled or shut down by default. Select Enabled (the default) if you want any new BGP sessions you configure to be live as soon as you save the configuration. Select Shut Down if you want any new BGP sessions you configure to be left in a shut down state when you save the configuration.

      For example, you might want to select the Shut Down option if you are planning to add a number of BGP sessions across your Virtual Cross Connects (VXCs) but know that you want to do some other router setup before you want them exchanging route information. When you are finished configuring your routers, you can then go into the relevant BGP sessions and enable them.

      The setting you choose here just sets the default state for the new BGP session. You can override this in the MCR Connection detail screen. For details on overriding the BGP state for an individual connection, see Shutting down a BGP connection.

    • For details on changing an MCR contract term, see MCR Pricing and Contract Terms.

  6. Click Save.

Editing a VXC

To edit a VXC

  1. Choose Networking > Services.
  2. Select an MCR or use the search filter to locate and select an MCR.
  3. Click the right arrow to expand the display to show VXCs.

  4. Select the VXC and select the VXC Configuration tab.

  5. Click Edit.

    Edit MCR

  6. Edit the VXC name, rate limit, or service level reference.

  7. Click Save.

For each VXC connected to an MCR you can configure one or more interfaces, BGP connections, or static routes.

To edit a VXC interface

  1. Choose Networking > Services.
  2. Select an MCR or use the search filter to locate and select an MCR.
  3. Click the right arrow to expand the display to show VXCs.

  4. Select the VXC and select the A-End Configuration tab.

  5. Click Edit.

  6. Enter one or more interface IP addresses in CIDR format. This value is the IP address for the interface and is the MCR IP address used for BGP peering to AWS.

  7. Click Save.

Configuring BGP

The Border Gateway Protocol (BGP) allows dynamic route table updates from the MCR across the VXC to the port. Enable one or more BGP peers for the MCR, up to a maximum of five. You configure BGP on a VXC connected to the MCR.

To configure BGP

  1. Choose Networking > Services.
  2. Select an MCR or use the search filter to locate and select an MCR.

  3. Click the right arrow to show all VXCs connected to the MCR.

  4. Select the VXC and select the A-End Configuration tab.

  5. Click Edit.

  6. Click Add BGP Connection.

    IP Details

  7. In the Basic tab, specify these values:

    • Local IP – Select the IP address on this interface that communicates with the BGP peer. The drop-down menu is autopopulated based on the address you specified in the connection detail.

    • Peer IP – Specify the IP address for the BGP peer. For example, if the local IP is 198.162.100.1, the peer IP address would be 198.162.100.2.

    • Peer ASN – The ASNAutonomous system number.
      A collection of connected IP routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain.
      of the target routing device that will terminate the BGP connection. The ASN range is from 2 to 4294967294. 4-byte ASNs are supported in the asplain format. For AWS cloud connectivity, enter the ASN of the AWS gateway.

    • Local ASN – The default ASN assigned to the MCR is 133937. For most configurations, the default ASN is appropriate. Optionally, you can specify another local ASN to override the default ASN on a per-peer basis.

      Enter a public or private ASN (for example, enter a number from 64512 to 65534). For most configurations, the default ASN is appropriate.

      The ASN range is from 2 to 4294967294, but the following ASNs are not available:

      • 8074, 8075, 12076, 65515 - 65520 (reserved in Azure)
      • 23456, 64496-64511, 65535 - 65551 (reserved by Internet Assigned Numbers Authority (IANA))
    • ASN Path Prepend – Enter the number of times to add the local ASN to the BGP path to prioritize route advertisements. Enter an integer within the range of 1 to 10.

      The ASN path length determines the route advertisement priority for outgoing BGP paths. The route with the shortest AS path has the highest preference, and it wins over any longer path advertisements. AS path prepending lengthens the path to lower the path priority. For example, 2 prepends the ASN to the existing AS path twice, creating an AS path length of 3.

      Setting an ASN prepend value is optional.

    • BGP Password – The shared key to authenticate the BGP peer. A shared key is optional when creating the VXC, but is required to set up the BGP peering. You can add it after you create the VXC. The shared key length is from 1 to 25 characters. The key can include any of these characters:
      a-z
      A-Z
      0-9
      ! @ # . $ % ^ & * + = - _

    • Description – Optionally, include a description that will help identify this connection. The minimum description length is from 1 to 100 characters.

    • BGP State – Shuts down the connection without removing it. The initial setting will be taken from the setting on the A-End of the MCR. Enabling or shutting down the BGP state does not impact existing BGP sessions. The BGP state only affects new VXCs. This setting overrides the MCR state for an individual connection. See Shutting down a BGP connection and Creating an MCR.

    Note

    If you have entered multiple CIDR ranges, the IP addresses are available for selection.

    Note

    Use a CIDR calculator to ensure that all data is valid and within range.

  8. Click Confirm.

Note

When creating an AWS Hosted Connection, while creating the virtual interface in the AWS console for this connection, you will match the values on the Basic tab.

To edit a BGP connection

  1. Select the VXC and select the MCR A-End Configuration or MCR B-End Configuration tab.
  2. Next to the connection, click Edit.
  3. Make your changes.
  4. Click Save.

For information on the BGP Advanced tab settings, see Configuring BGP Advanced Settings.

Configuring static routes

Static routes establish reachability to peers in place of BGP connections that provide dynamic routing. You configure static routes to provide connectivity to a customer device that doesn’t support BGP or to a target device that requires manually configured addressing and routes. With static routes, you need to manually update any topology changes.

An MCR supports up to 50 static routes.

To add a static route

  1. Select the VXC and select the A-End Configuration tab.
  2. Click Edit.
  3. Under Static Routes, in the Prefix field, specify the IPv4 or IPv6 destination network address in CIDR notation.
  4. Specify the IPv4 or IPv6 address of the next-hop router. The address must be in the same subnet as the interface but it can’t match the interface IP address.
  5. Optionally, include any notes that will help identify this static route. The description range is from 1 to 100 characters.
  6. Click Save.
  7. Update the MCR B-End configuration, if necessary.
  8. Click Save.

To view static routes, see Viewing Traffic Routing through MCR Looking Glass.

Verifying the BGP configuration

The MCR Looking Glass provides single-screen visibility into the BGP configuration. For details, see Viewing Traffic Routing through MCR Looking Glass.

To view the BGP connection status

  1. Select the VXC.
  2. Select the VXC and select the A-End Configuration or B-End Configuration tab.
  3. Under BGP Connections, the status appears in the BGP State column.

Troubleshooting BGP

If the service displays a status issue, verify these items:

  1. Select the VXC and select the A-End Configuration or B-End Configuration tab.
  2. Under BGP Connections, verify that the correct local ASN is in use for the A-End of the VXC.
  3. Verify that the correct peer IP address is in use.
  4. Click the Gear Icon gear icon and click Edit to verify that the correct BGP MD5 password is in use for the A-End of the VXC.

If the BGP configuration looks correct:

  • Make sure that a BGP peer is not blocking ingress or egress from TCP port 179 (BGP) and other relevant ephemeral ports.

  • Verify that a BGP peer is not advertising more than 100 prefixes to AWS. The maximum number of advertised routes to AWS is 100. The BGP session is disabled if it exceeds the prefix limit of 100 advertised routes.

Shutting down a BGP connection

Use this setting to temporarily disable the BGP session without removing it. BGP shutdown provides a way to administratively shut down a BGP connection while setting up a new route, performing maintenance, troubleshooting, and so on.

To temporarily disable a BGP connection

  1. Select the VXC and select A-End Configuration or B-End Configuration.

  2. After the BGP connection details, click Shut Down.

  3. Click Yes to confirm.


Last update: 2023-01-21