Configuring an MCR

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

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.
   

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 – By default, BGP is enabled and the connection will actively connect to the peer. You can shut down the connection without removing it. See BGP shutdown.
     

   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.
   

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

5. Specify the IP address of the next-hop router.
6. Optionally, include any notes that will help identify this static route.
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.
   

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.
   

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 service 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

By default, BGP connections are enabled and will actively connect to the BGP peer. You can 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. In the MCR Connection detail page, click +Add BGP Connection.

2. In the BGP Connection page, after BGP State, click Shut Down.

3. Click Add.