Deployment Modes of Citrix SD WAN

Citrix SD-WAN offers flexible options for deployment depending on use cases, or high availability requirements in the primary Data Center, Branch, or Cloud Resource locations.

Inline
Hardware appliances can be deployed seamlessly in the path between the LAN and the WAN edge network. If the device goes offline for any reason the physical Ethernet connection, through the equipment between switches or routers, remains intact.

Virtual Inline
An approach that offers similar usage to Inline, without the need to physically interrupt the primary data center network. The Citrix SD-WAN equipment is implemented on a VLAN adjacent to the Edge router which uses policy routing to direct pertinent traffic to it for optimization.

Edge / Gateway Mode
Takes over responsibility for WAN edge networking including terminating leased lines, routing, firewall, and internet proxy filtering in addition to providing full SD-WAN functionality. This mode allows enterprises to consolidate branch hardware to maximize network throughput, availability, and security while minimizing complexity and cost.

Fail-to-Wire
Hardware platforms include fail-to-wire (Ethernet bypass) cards for direct in-path deployment. If power fails, a relay closes, and the input and output ports become electrically connected, allowing the Ethernet single to passthrough from one port to the other, defaulting to the existing underlay network.

Find more: SD-WAN vs. MPLS

High-Availability
The various deployment options (Inline, Virtual Inline, Edge) support high-availability. A pair of devices can be deployed at a site location in Active/Standby roles. This high availability deployment operates similar to Virtual Router Redundancy Protocol (VRRP), ensuring the SD-WAN Overlay is continuously active.

Geographically Distributed MCN
A secondary data center or branch site can be assigned the role of Secondary MCN (also known as GEO MCN). This site takes the responsibility of the primary data center SD-WAN and ensure that the SD-WAN Overlay continues to operate until the primary site comes back online.

Future of SD-WAN: Where next?

We believe that SD-WAN under its current definition is not an end in itself. All indications are that enterprises are becoming increasingly cloud-centric, and we see no sign of this trend reversing. SD-WAN will no doubt be a key component of the multicloud ecosystem – but it will require an evolution beyond the confines of what is currently being packaged and sold.

In short, existing SD-WAN offerings are just the first step on a longer journey towards integrated, software-driven WAN operations and networking on a broader scale. Enterprises and vendors planning SD-WAN rollout would do well to consider how that evolution could unfold.

Learn more: SDN vs MPLS - The Difference in the Details

As with any new technology, there are multiple pathways that this evolution could follow – none of which are yet well-understood. STL Partners has identified three emerging evolution pathways, which we explain in detail below. The options are:

  1. SD-WAN used as the first step towards SD-Branch: SD-WAN is deployed as a stepping stone technology towards more advanced, integrated management of enterprises’ LANs and branches alongside the WAN.
  2. SD-WAN sold “as a Service”: SD-WAN starts to be offered as a more fully cloud-based software service, free from vendor or hardware-based constraints
  3. SD-WAN used as an enabling component of edge/IoT platforms: SD-WAN features and infrastructure are integrated with service providers’ edge computing and Internet of Things (IoT) platforms, with sales focus on enterprise automation and process optimisation, rather than the SD-WAN component itself

SD-WAN explained: The ultimate guide to SD-WAN architecture

The software-defined wide area network (SD-WAN) is a quickly maturing technology widely adopted by enterprises and organizations as a cost-effective way to connect branch offices to their own data centers and to SaaS and other cloud-based applications.
This guide to SD-WAN links you to articles that will walk you through all things SD-WAN. The collection explains the basics of SD-WAN technology, how it works, buying options, planning for implementation, best practices and troubleshooting advice. This guide also offers insight into how SD-WAN architecture will evolve over the next few years.

Articles in this guide cut through the confusion the range of SD-WAN options might present and help enterprises make informed decisions about how SD-WAN fits into the organization’s network environment. Don’t forget to click on the links throughout this article to learn even more about SD-WAN technology.

Introduction to SD-WAN
The wide area network (WAN) has always posed significant challenges for organizations with distributed workforces. The need for fast and reliable application performance, the high cost of dedicated network circuits and the complexities of day-to-day tasks such as configuration, monitoring and management are all magnified across a WAN. Whether an organization grows organically or through mergers and acquisitions, it can be challenging for IT teams to deploy edge gear quickly to connect users to business applications.