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AWS Direct Connect
User Guide

Virtual Interfaces

You must create a virtual interface to begin using your AWS Direct Connect connection. You can create a private virtual interface to connect to your VPC, or you can create a public virtual interface to connect to AWS services that aren't in a VPC, such as Amazon S3 and Amazon Glacier. You can configure multiple virtual interfaces on a single AWS Direct Connect connection. For private virtual interfaces, you need one private virtual interface for each VPC to connect to from the AWS Direct Connect connection.

To connect to other AWS services using IPv6 addresses, check the service documentation to verify that IPv6 addressing is supported.

We advertise appropriate Amazon prefixes to you so you can reach either your VPCs or other AWS services. You can access all AWS prefixes through this connection; for example, Amazon EC2, Amazon S3, and Amazon.com. You do not have access to non-Amazon prefixes. For a current list of prefixes advertised by AWS, see AWS IP Address Ranges in the Amazon Web Services General Reference.

Note

We recommend that you use a firewall filter (based on the source/destination address of packets) to control traffic to and from some prefixes. If you're using a prefix filter (route map), ensure that it accepts prefixes with an exact match or longer. Prefixes advertised from AWS Direct Connect may be aggregated and may differ from the prefixes defined in your prefix filter.

To use your AWS Direct Connect connection with another AWS account, you can create a hosted virtual interface for that account. A hosted virtual interface works the same as a standard virtual interface and can connect to public resources or a VPC.

A sub-1G connection only supports one virtual interface.

Prerequisites for Virtual Interfaces

To create a virtual interface, you need the following information:

  • Connection: The AWS Direct Connect connection or link aggregation group (LAG) for which you are creating the virtual interface.

  • Virtual interface name: A name for the virtual interface.

  • Virtual interface owner: If you're creating the virtual interface for another account, you'll need the AWS account ID of the other account.

  • (Private virtual interface only) Connection to: For connecting to a VPC in the same region, you need the virtual private gateway for your VPC. The ASN for the Amazon side of the BGP session is inherited from the virtual private gateway. When you create a virtual private gateway, you can specify your own private ASN. Otherwise, Amazon provides a default ASN. For more information, see Create a Virtual Private Gateway in the Amazon VPC User Guide. For connecting to a VPC through a direct connect gateway, you need the direct connect gateway. For more information, see Direct Connect Gateways.

  • VLAN: Each virtual interface must be tagged with a new, unused customer-provided tag (VLAN ID) that complies with the Ethernet 802.1Q standard. This tag is required for any traffic traversing the AWS Direct Connect connection. The number must be between 1 and 4094.

  • Address family: A virtual interface can support a BGP peering session for IPv4, IPv6, or one of each (dual-stack). You cannot create multiple BGP sessions for the same IP addressing family on the same virtual interface.

  • Peer IP addresses: The IP address ranges that are assigned to each end of the virtual interface for the BGP peering session.

    • IPv4:

      • (Public virtual interface only) You must specify public IPv4 addresses (/30) that you own.

      • (Private virtual interface only) Amazon can generate private IPv4 addresses for you. If you specify your own, ensure that you specify private CIDRs for your router interface and the AWS Direct Connect interface only (for example, do not specify other IP addresses from your local network).

    • IPv6: Regardless of the type of virtual interface, Amazon automatically allocates you a /125 IPv6 CIDR. You cannot specify your own peer IPv6 addresses.

  • BGP information: A virtual interface must have a public or private Border Gateway Protocol (BGP) Autonomous System Number (ASN) for your side of the BGP session. If you are using a public ASN, you must own it. If you are using a private ASN, it must be in the 64512 to 65535 range. Autonomous System (AS) prepending does not work if you use a private ASN for a public virtual interface. You can provide your own MD5 BGP authentication key, or you can let Amazon generate one for you.

  • (Public virtual interface only) Prefixes you want to advertise: Public IPv4 routes or IPv6 routes that you will advertise over BGP. You must advertise at least one prefix using BGP, up to a maximum of 1,000 prefixes.

    • IPv4: The IPv4 CIDR must not overlap with another public IPv4 CIDR announced via AWS Direct Connect. If you do not have public IPv4 addresses, open a ticket with AWS Support.

    • IPv6: Specify a prefix length of /64 or shorter.