Configuring an MCR

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

Editing an MCR

To edit an MCR

  1. In the Megaport Portal, go to the Services page.
  2. Select the MCR you want to edit.
    Edit MCR

  3. You can edit any field on the MCR Configuration page, except the rate limit, which is fixed for the duration of the service.

    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 BGP setup screen. For details on overriding the BGP state for an individual connection, see Shutting down a BGP connection.

  4. Click Save.

Editing a VXC

For each VXC enabled with Q-in-Q and connected to an MCR you can configure one or more interfaces, IP addresses, BGP connections, or static routes.

To edit a VXC interface

  1. Select the connection and select the A-End or the B-End.
  2. Step through the procedures to configure your VXC. The procedures will vary slightly depending on your destination type.

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.

To configure BGP

  1. Next to an MCR, click +Connection.
  2. Follow steps 1 through 5 to create a VXC as described in To connect a VXC.
  3. In the New Connection page, under MCR Connection detail, enter an IP address and subnet mask to configure on this interface and click +Add.
    IP details

  4. Click +Add BGP Connection and specify these values:

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

    • Peer IP – 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 ASN of the target routing device that will terminate the BGP connection. The ASN range is from 1 to 4294967294.

    • BGP Auth – The shared key to authenticate the BGP peer. The shared key length is from 1 to 25 characters. The key can include any of these characters:

      a-z
      A-Z
      0-9
      ! @ # ? . $ % ^ & * + = -

      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.

    • 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 BGP shutdown and Creating an MCR.
      BGP details

    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.

  5. Click Add.

To edit a BGP connection

  1. Select the connection and select the A-End or the B-End.
  2. Select Edit.

For details on configuring other BGP settings, see 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 ten static routes.

To add a static route

  1. Select the VXC.
  2. Select A-End.
  3. In the MCR Connection detail page, click +Add Route.
    Static route

  4. Specify the IPv4 or IPv6 destination network address in CIDR notation.

  5. Specify the IPv4 or IPv6 address of the next-hop router. The address must be in the same subnet as the interface but can’t match the interface IP address.
  6. Optionally, include any notes that will help identify this static route. The description range is from 1 to 100 characters.
  7. Click Add.

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

Source NAT assignment

Network Address Translation (NAT) allows flexibility in designing a scalable and secure multi-vendor, multi-cloud, or hybrid cloud scenario. Source NAT translates the source IP address of a packet leaving the MCR. When you assign a NAT IP address in MCR, all packets leaving the interface use that IP address as their source IP address. Enable this feature when NAT is required for a connection, for example, when you need to translate several private IP addresses into a single public IP address to meet cloud service provider requirements.

NAT assignment is optional.

For details on how MCR performs NAT to support public peering types to cloud service providers, see How the MCR performs NAT.

To enable source NAT on the interface

  1. In the MCR Connection detail page, next to NAT IP Address, select an IPv4 address from the drop-down list. All packets leaving this interface will have their source NAT rewritten to this address.

  2. Click Next.
    NAT assignment

For information on the BGP BFD and MED settings, see Configuring BGP Advanced Settings.

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 status

  1. In the Portal, click Services.
  2. Select the VXC.
  3. Click A-End or B-End.
    BGP status

Troubleshooting BGP

If the Services > MCR Connection Detail page displays a status issue, verify these items:

  1. Select the VXC and select A-End. Under BGP Connections, verify that the correct local ASN is in use for the A-End service of the VXC.
  2. Verify that the correct peer IP address is in use.
  3. 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, and so on.

To temporarily disable a BGP connection

  1. Log in to the Portal and choose Services.

  2. Select the VXC you want to disable and select the A-End or B-End.

  3. After Connection Details, click Shut Down.

    BGP shutdown

  4. Click Yes to confirm.


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