Cloud WAN service insertion

Service insertion allows you to steer same-segment or cross-segment traffic using network functions deployed in VPCs or on-premises networks attached to Cloud WAN. Network functions can be third-party network or security appliances such as NGFW, IDS, IPS appliances or native AWS network firewall or Gateway Load Balancer services. Using either the AWS Network Manager console or a JSON file, you'll create a version of one of your core network policies and create a network function group that contains a set of core network attachments where your network functions reside. You'll then specify a segment or segment pairs for which traffic needs to be redirected to those network functions. Once the policy version is deployed and your new core network LIVE, Cloud WAN will automatically redirect network traffic between the segments to the specified core network attachments for the respective network function group. This redirection works for both same Region and cross-Region traffic on the core network. Service insertion works on both east-west (VPC to VPC) and north-south (VPC to the Internet or on-premises location) traffic.

To create a core network that includes service insertion, you'll need to do the following:

1. Create a policy version of a current policy. The initial policy you deploy when you create your first core network doesn't include any service insertion features. To do this you'll create a version of an existing policy and add the service insertion features. You can do this using either the AWS Network Manager console or through a JSON file.

   You can create a policy version containing the service insertion action using either the AWS Network Manager console or through creating a JSON file which you can also create using the console:

   • To create a policy version using the console, see Create a core network policy version using the console.

   • To create a policy version using a JSON file, see Create a core network policy version using JSON.

2. Using either the console or within the JSON file you'll do the following:

   1. Configure your core network. Set the BGP and ASN for this core network policy.

   2. Add segments. Add segments to your core network policy. Segments with cross-segment or same-segment traffic that must be steered via the network functions. Based on your policy configuration, Cloud WAN will automatically propagate routes from VPCs and networks associated to the network function groups and redirect VPC-to-VPC or VPC-to-Internet or on-premises traffic through a network functions group.

   3. Create a network function group. The network function group is a collection of attachments specifically used for network or security functions.

   4. Set segment actions. Segment actions allow you to share segments, create routes, and create a service insertion action.

      For the service insertion action, you can create a send via action which sends traffic east-west between all VPCs. Or you can create a send to action, which first sends traffic to a security appliance and then out from the appliance. For example, you might create segment action using send via . With this action, traffic is first routed to the Inspection VPC and then out from the Inspection VPC to the internet or on-premises location. Traffic does not re-enter the Inspection VPC. See Traffic actions and modes below for more information about traffic actions and modes.

      By default. Cloud WAN will select an attachment in one of the two Regions used for the network function. For example, if the network function is steering traffic to an Inspection VPC, and that Inspection VPC exists in only one Region, Cloud WAN uses the Region where the Inspection VPC resides to steer all cross-Region traffic. If the Inspection VPC exists in both Regions, service insertion will deterministically choose which Region to use based on the default Region priority list. However, when setting the segment actions, you can choose the Region priority order as well as choose the preferred Region to use. If the Inspection VPC doesn't exist in either Region, Cloud WAN uses the fallback Region specified in the segment policy. You can only specific a single fallback Region per segment policy.

   5. Create an attachment policy for the network function group. Add the network function group to an attachment policy. The attachment policy then controls the order in which the network function group runs. When creating an attachment policy rule for a network function group, the network function group must include an attachment.

3. Deploy the policy version. See Deploy a policy version.

Benefits

• Simplified routing — Service insertion allows for more simplified routing. You might need inter-VPC or VPC to internet or on-premises traffic to be routed through network appliances, such as network firewalls or load balancers. With Cloud WAN service insertion you can more easily steer network traffic to network or security appliances deployed in VPCs or in on-premises. This allows you to create and manage sometimes complex routing configurations or third-party automation tools.

• Ease of deploying multi-Region inspection — You might deploy Cloud WAN in multi-Region networks to support Region expansion or disaster recovery use cases. Service insertion simplifies mutli-Region deployment, allowing you to steer both intra-Region and inter-Region traffic through your security infrastructure without having to set up complex multi-Region network configurations.

Traffic actions and modes

Service insertion supports the following traffic actions and modes for both east-west and north-south traffic.

• Send via — Traffic flows east-west between VPCs. All traffic for the service insertion action is first sent via a specific segment to the security appliance and then out to other VPCs.

  • Single hop — Traffic traverses a single intermediate attachment, using the deterministically preferred source or destination Region. You can set a list of Regions to use, as well as setting a preferred Region to use as a priority.

  • Dual hop — Traffic traverses inserted attachments in both the source and destination core network edges. For this option, the inspection attachment should be located in both Regions for each service insertion-enabled segment.

• Send to — Traffic flows north-south. That is, traffic flows into the network appliance, such as an Inspection VPC, and out to the Internet or to an on-premises location. Traffic does not re-enter the AWS cloud.

Attachments

Within a network function group you can specify a set of core network attachments where your network functions will reside. For example, the attachment might be a VPC that you use for inspection. You'll then add a segment or segment pair to this attachment that will be redirected to the network functions group and then to the security appliance. Cloud WAN automatically redirects traffic on any segment you add to that VPC when creating a service insertion action to that group both in the same Region and cross-Region within the core network.

In order to make an attachment be part of the network function group correctly, service insertion relies on the key-value pair tags added to an attachment. When creating an attachment you'll need to add the relevant tag to each attachment. For example, you might want to use a particular attachment as an Inspection VPC. You could add a tag with the key name Inspection VPC and then a key value of InspectionVpcs. The same tag should be applied to any attachment you add to that network function group. When you create a service insertion function, you'll add an attachment policy rule that relies on the key tags and values added to those attachments in order to process the tag key. In this example, you'd add a policy rule that identifies the tag Inspection VPC and the key value of InspectionVpcs. Attachment policy rules can be created using either the AWS Cloud WAN console or through a JSON file. For the steps for either method, see Attachment policies.

The following are the supported core network attachments:

• Connect

• Transit gateway route table

• VPC

• VPN

Considerations

• Attachments — You can either associate an attachment with a segment or with a network function group, but it can't be associated with both.

• Isolated mode — Isolated mode is required for all segments that require service insertion. This ensures that there's no direct connectivity between attachments associated for the segment by bypassing the network functions that require service insertion.

• Appliance mode — Appliance mode must be enabled on the Inspection VPC to ensure that traffic moves in both directions.

Pricing

There are no additional charges for using service insertion other than the standard AWS Cloud WAN pricing charges. Information about Cloud WAN pricing can be found here: AWS Cloud WAN Pricing.