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title: "SLA-based network selection"
canonical: "https://docs.aryaka.com/space/KNOW/1284505610/SLA-based%20network%20selection"
format: markdown
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Aryaka's hybrid WAN functionality allows you to configure the following types of networks at a site: VPN Path Aryaka VPN Path Internet MPLS Cloud transport network (for example, Azure Virtual WAN) Cloud security connectors (for example, Zscaler, Palo Alto Networks, and Symantec) Direct Internet You can then decide what traffic to redirect or reroute to these networks using WAN Routing rules. These rules are enforced by an ANAP at a site. When traffic enters an ANAP, these rules determine if the traffic is denied or routed to one of the networks configured for the site. If the traffic is destined to a connected remote site, it can traverse the following three networks: VPN Path Aryaka VPN Path Internet MPLS Each network has its own routing table that is built using static configuration or BGP. When a network is used for a specific type of traffic, it is then specified in the WAN Routing rule configuration. An ANAP's default WAN Routing rule is to look up all relevant route tables and match the longest prefix for the routes in the routing table to decide which network is used. You can override this default prefix matching behavior by specifying  match rules  or by creating WAN Routing rules (either  for an individual site ,  for all sites , or using an  application policy ) that decide where to route the traffic. To do this, you must create a prioritized list of all networks that you want the ANAP to consider when routing the traffic and then specify additional configuration to determine which network is preferred. The preference is determined using a configuration that includes the following options: Route Sequential—Specifies that the ANAP only uses the sequence in which the networks are configured (that is, use the ordering in the prioritized list). This ignores the cost, MED, and AS Path Prepend of the routes in the routing table. Route Parallel—Specifies that the ANAP uses the route with the lowest cost to decide which network to use. If two routes have equal costs, the order in the prioritized list is used to decide which network to use. Route Parallel Longest Prefix Match—Specifies that the ANAP uses the routing table to decide which network to use. First it looks for the longest prefix match and if multiple matches are found, it uses the lowest routing cost to determine the network. Lastly, if two routes have the same cost, then the order in the prioritized list is used to decide which network to use. Route Parallel IP SLA—Specifies that the ANAP uses the networks' health to decide which network is best suited for the application.  Measuring the health of the networks SLA-based network selection is available only for VPN Path Aryaka and VPN Path Internet networks. The ANAPs at either end of a site pair measure the health of the network using specifically designed  SLA protocol data units  that work with existing traffic and measure the following:  Loss  Latency Jitter In the absence of traffic, ICMP carries these data units once every six seconds to help the ANAPs determine the health of the network. The ANAPs also track the available bandwidth on each network. See  Adaptive bandwidth management  for details about how bandwidth is allocated to networks. SLA profiles User-defined SLA profiles determine whether a network is suitable for use for a specific application type. SLA profiles are configured to consider the following: Loss Jitter Available bandwidth  The following criteria are required for a network to be in compliance with an SLA: Experiencing loss at a level less than the profile's configured threshold. Experiencing jitter at a level less than the profile's configured threshold. Has available bandwidth greater than the profile's configured threshold. A network that does not meet  any  of these criteria is  not  in compliance with the SLA. Multiple SLA profiles can be configured by based on need. For example, a VOIP application profile can be created to be more sensitive to loss, whereas a video conferencing application may be more sensitive to jitter, and a data replication application may need a certain amount of bandwidth available to it. For details on how to create an SLA profile, see the  Manage SLA profiles  help topic.  Choosing a network When deciding the route that certain traffic must take using WAN Routing rules or application-based policies, choose the Route Parallel IP SLA option and specify which SLA profile applies to the traffic. The Route Service Engine on the ANAP searches all relevant routing tables for routes with the longest prefix match. If multiple networks have the same route advertised through them, then SLA is used to decide which network to use as follows: If one of the two networks is in compliance with the SLA, use that network. If both networks are in compliance with the SLA, use the network with lower latency. If neither network is in compliance with the SLA, use the network with the highest priority in the ordered list included in the WAN Routing rule. Related topics Manage SLA profiles Create site-level WAN Routing policies Create customer-level WAN Routing policies