Describes how service controllers and service nodes interact in an AppQoE cluster and shows a sample deployment topology.
An AppQoE service cluster is a site-level deployment in which service controllers connect to external service nodes to process traffic.
With Cisco Catalyst SD-WAN supporting the creation of external service nodes from Cisco IOS XE Catalyst SD-WAN Release 17.4.1a, service nodes are decoupled from the intercepting edge router or the service controller. You now have the option to configure supported devices as standalone service controllers and connect them to devices that are configured with the service node role.
Using Cisco SD-WAN Manager device templates, you can configure the following roles on supported devices:
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Service Node
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Service Controller
How Service Controllers and Service Nodes Interact
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In Cisco IOS XE Catalyst SD-WAN Release 17.4.1a, only Cisco Catalyst 8000V Edge Software (Cisco Catalyst 8000V) can be configured with the service node role. When you configure Cisco Catalyst 8000V instances with the service node role, a default AppQoE template is attached to them, which cannot be modified.
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Service nodes in a site and the service controllers that they are connected to form a service cluster.
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Service nodes do not communicate with each other and are not aware of the other service nodes in the cluster.
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Service controllers initiate communication with the service nodes connected to them. This configuration is set up in the AppQoE feature template associated with a device template that has the service controller role defined.
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Service controllers and service nodes can be adjacent to each other, or next or multiple hops away.
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Service controllers communicate with the service nodes through service VPNs. However, service nodes communicate with service controllers through transport VPN or VPN 0.
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Service nodes only respond to the service controller that they are connected with.
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In Cisco SD-WAN Manager, the health of each AppQoE service node is represented by the colors Green or Yellow. Only nodes with Green status are considered for distribution of new flows. Any ongoing flows to service nodes showing as Yellow are redirected.
Sample Topology
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*SN: Service node (up to 64 per controller) |
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*SC: Service controller (up to 8 per site) |
The image above shows an example of Cisco Catalyst SD-WAN deployment with service nodes that are external to the service controller. The image shows the deployment at both a branch site and a data center. Cisco IOS XE Catalyst SD-WAN devices at the data center and branches form an AppQoE cluster with service nodes at their respective sites.