policybased

Policybased refers to an approach in computing and networking where decisions are driven by formal policies rather than static rules or default behaviors. In computing, policybased management and policy-based routing are examples where organizational or operational policies determine how tasks are performed, resources are allocated, or traffic is forwarded.

In networking, policybased routing (PBR) allows administrators to influence the path that packets take through a network based on attributes other than the destination address. PBR policies can match on source and destination, protocol, application type, user identity, time of day, and other header or metadata, and can direct traffic to a specific next hop, a particular routing table, or apply QoS or shaping actions.

Implementation details: Various vendors provide policy-based constructs such as route maps, policy statements, access control lists, or firewall filters to define the match criteria and associated actions. PBR is commonly used for traffic engineering, WAN optimization, and security separation, and is often deployed alongside or in support of software-defined networking and hybrid cloud architectures.

Benefits and caveats: It provides granular control and can improve performance or policy compliance, but adds configuration complexity. Because PBR may bypass dynamic routing, incorrect policies can lead to suboptimal routes or routing loops if not carefully managed, and changes require thorough testing.

See also: policy-based management, routing, traffic engineering, QoS, SD-WAN, routing protocol.