Manual Chapter : Introduction to the BIG-IP SFC Manager

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BIG-IP LTM

  • 15.0.0, 14.1.0
Manual Chapter

Introduction to the BIG-IP SFC Manager

Introduction to the BIG-IP SFC Manager

Technology organizations today are becoming increasingly interested in transitioning from a traditional traffic steering Gi-LAN architecture to an architecture based on network service header (NSH) service function chaining. In response to this interest, F5 has enhanced the BIG-IP system to operate as a lightweight Service Function Chaining (SFC) manager.

The lightweight SFC Manager is a BIG-IP system that uses network service headers to implement and control service chaining on a group of network devices, without the full set of features that would be required to compete with other industry software-defined networking (SDN) controller solutions.

Benefits of the SFC Manager

As a lightweight SFC manager, the BIG-IP system:

  • Smoothly transitions customer BIG-IP devices to an SFC architecture without the need for an external SDN controller.
  • Provides an SFC architecture that is solution-independent and vendor-agnostic.
  • Supports the ability to configure BIG-IP devices as service chain classifiers and service function forwarders (SFFs). This is in line with RFC 7665.
  • Supports the ability to select previously-created VLAN and tunnel interfaces that serve to connect BIG-IP SFFs to service functions (SFs).
  • Will operate in the future as a mediation layer, to accept configuration data from an external SDN controller.
  • Can be deployed in both NFV and non-NFV network environments.

Overview of the SFC Manager configuration

In the sample SFC configuration described in this document, a BIG-IP device in a group of BIG-IP devices operates as the lightweight SFC manager. Another BIG-IP device operates as both a service classifier function (SCF) and a service function forwarder (SFF), and a third BIG-IP device operates as an SFF only. Although an SFF can generally be associated with multiple SFs, in the sample configuration described in this document, each SFF is associated with either one or two service functions (SFs).

Figure 1 shows the basic service function chaining architecture that this document describes. Notice that in this SFC configuration, there is a single VXLAN-GPE tunnel that connects the service nodes.



Service function chain components

Configuring a BIG-IP device as a lightweight SFC manager requires you to perform these tasks:

  • Download the iAppLX RPM file and import it to the BIG-IP system that you intend to use as the SFC Manager.
  • After the SFC Manager iAppLX is ready, run the SFC Manager to configure SFC objects. A green dot displayed next to Service Function Chaining Manager indicates that the SFC Manager is installed and ready to use.
Important: Before configuring service chaining, you must create some prerequisite configuration objects on various devices on the network. These objects include VXLAN-GPE tunnels, VLANs, IP addresses, and others, as specified in the following section.

Prerequisite SFC tasks

Before you use the SFC Manager to create an SFC configuration, you must log in locally to each BIG-IP device that is to operate as a service function forwarder (SFF), and create some prerequisite BIG-IP objects. You must also log in to each device that is to operate as a service function (SF) and create other prerequisite objects.

After you create these objects, you can specify them from the SFC Manager as you create the service function chain configuration.

Figure 2 explains the prerequisite objects that you must create on each device, in the order suggested, for the sample configuration described in this document. The list is organized according to the specific service nodes that will make up the service chain configuration.

Note: In Figure 2, and in the subsequent SFC Manager tasks, all devices and configuration objects show sample names. When you create your own prerequisite objects and service chain components, make sure to use names that make sense for your configuration.

Prerequisite SFC tasks

Note: No prerequisite objects are required for an SF of type Virtual, as it consists of the virtual server that you created on sff2.
Note: If you intend to include more than two SCF/SFFs in your configuration, you must use the same subnet for overlay addresses across all SCF/SFFs.