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See: 7665 on datatracker.ietf.org

The title of this RFC is “Service Function Chaining (SFC) Architecture (RFC 7665).”

RFC 7665 defines the architecture for Service Function Chaining (SFC), which refers to the process of creating an ordered set of network services, such as firewalls, load balancers, and deep packet inspection systems, that a particular data flow must pass through. SFC allows for more dynamic and flexible insertion of services into a network path, unlike traditional static models where network traffic is manually directed through a pre-defined path of services. The network architecture provided in RFC 7665 is intended to support complex networking environments, including cloud services and Network Function Virtualization (NFV). The related RFC is RFC 7567, which discusses the principles of NFV and its application in network automation. https://en.wikipedia.org/wiki/Service_function_chaining https://tools.ietf.org/html/rfc7567

The primary purpose of RFC 7665 is to provide a standardized framework for deploying SFC in networks. By doing so, it enables network operators to dynamically chain together service functions that can be applied to specific traffic flows based on policy requirements. For example, in a network where certain data flows must be inspected by a firewall, encrypted, and load balanced before reaching their destination, SFC can automate this chain without requiring manual configuration for each step. This makes it easier to apply complex policies and optimize resource usage in modern data centers and service provider networks. The related RFC is RFC 7426, which provides an architectural overview of SDN and its relevance to SFC. https://en.wikipedia.org/wiki/Software-defined_networking https://tools.ietf.org/html/rfc7426

RFC 7665 describes the components of the SFC architecture, including the Service Function Forwarder (SFF), Service Function Path (SFP), and Classifier. The Classifier is responsible for identifying which data flows need to be chained through specific services based on pre-defined policies. Once classified, the SFF ensures that the traffic is directed along the correct SFP, which specifies the order in which service functions are applied. This flexible architecture enables operators to define multiple service chains for different types of traffic, providing granular control over how network services are applied to each flow. The related RFC is RFC 7664, which discusses the deployment of service functions in virtualized environments. https://en.wikipedia.org/wiki/Virtualization https://tools.ietf.org/html/rfc7664

A critical component of RFC 7665 is its focus on supporting both physical and virtual network functions. In traditional networks, service functions are often implemented as physical appliances that require manual intervention to configure and manage. In contrast, modern networks, especially those leveraging NFV, implement service functions as virtualized instances that can be dynamically instantiated, scaled, and managed. SFC architecture supports this by allowing service functions to be deployed in virtualized environments while maintaining the flexibility and scalability of the service chain. The related RFC is RFC 7365, which addresses the challenges of deploying virtualized network functions. https://en.wikipedia.org/wiki/Network_function_virtualization https://tools.ietf.org/html/rfc7365

RFC 7665 also emphasizes the importance of security in SFC architectures. Since data flows traverse multiple service functions, including sensitive ones such as firewalls and encryption services, it is essential to ensure that traffic integrity is maintained throughout the chain. RFC 7665 recommends implementing authentication and encryption mechanisms between service functions to protect the integrity and confidentiality of the data. The related RFC is RFC 5246, which defines the Transport Layer Security (TLS) protocol used to secure communications in SFC architectures. https://en.wikipedia.org/wiki/Transport_Layer_Security https://tools.ietf.org/html/rfc5246

Another key aspect of RFC 7665 is the support for multi-tenancy in service function chains. In multi-tenant environments, different customers or services may have different security and performance requirements. RFC 7665 enables the creation of isolated service function chains for each tenant, ensuring that their traffic is processed by the appropriate set of service functions without interference from other tenants. This isolation is critical for maintaining security and compliance in shared infrastructure environments, such as cloud service providers. The related RFC is RFC 8485, which focuses on multi-tenant service chaining and isolation mechanisms. https://en.wikipedia.org/wiki/Multi-tenancy https://tools.ietf.org/html/rfc8485

The title of this RFC is “Service Function Chaining (SFC) Architecture (RFC 7665).” RFC 7665 provides a comprehensive framework for deploying and managing Service Function Chains in modern networks. By allowing network operators to dynamically define and manage service chains based on traffic and policy requirements, SFC simplifies the process of applying network services such as firewalls, load balancers, and encryption mechanisms to specific data flows. With its support for both physical and virtualized environments, SFC plays a critical role in enhancing the flexibility, scalability, and security of networks, especially in cloud and NFV deployments.