“Segment routing is a game changer,” years ago as efforts to build out global A simpler solution How Segment Routing is according to Craig Hill, distinguished networks were simply becoming “too Segment routing removes the architect at the U.S. Public Sector costly and too difficult,” said Dorman. requirements for multiple protocols division of Cisco Systems. “What and network-wide synchronization, Changing the Limitations in US segment routing has done is Prior to segment routing, multi-protocol and their state, that traditional MPLS dramatically reduce the complexity in label switching (MPLS) packets were added, while still providing the same the network while adding key feature forwarded using label switching instead services and reducing the complexity Federal Network Architectures enhancements,” he said. Organizations of IP-based routing—which meant of management and operations. with large-scale networking demands the routers forwarded traffic based A simpler approach for routing data that also works with legacy systems are already putting segment routing on the label and not the destination It utilizes a “source routing” technique to work. address. This required only the “edge” in which the sending router specifies is poised to help agencies reboot their networks—and lower their costs. routers to perform an IP lookup, while the route that the packet of information “Segment routing has been growing intermediate “core” routers performed will take through the network—akin like wildfire in the service provider only a label lookup. to a driver choosing a preferred route, By FedScoop Staff market,” said Joe Dorman, a solutions depending on traffic conditions—rather architect at Cisco. He pointed to Cisco This paradigm allowed an IP network than the path being chosen based customer data that shows a significant to offer an entire set of transport on the packet’s destination only. uptick in segment routing adoption services that has been in operation for The result is greater control, which over the past five years among cloud the last 20 years for service providers. can be important when service level providers and large-scale enterprises. agreements (SLAs) need to be met. “Now we’re starting to see it creep into Unfortunately, MPLS didn’t remove our larger federal and other customers any complexity from an existing More fundamentally, segment as they deal with the complexities of network, and actually added it through routing consolidates all the delivery running wide area networks.” additional protocols. Adding more protocols and encodes them into the complexity was that each MPLS node packet header as an ordered list of Inability to scale required the state to be synchronized instructions, or segments, that routers The need for a simpler networking across the entire network. As the size can read and redirect accordingly. solution became evident to big IT of networks grew, so did the state and Additionally, it natively supports fast services providers—and networking complexity, making it more difficult to rerouting around failures, without equipment makers like Cisco—several operate and manage. the need for complex backup traffic ederal agency executives their operating costs and enhance to encode and execute routing engineering tunnel provisioning. face a common conundrum: their security controls simply by taking instructions for information packets. F how to simplify their advantage of these newer capabilities. Moreover, it’s ideally suited for the infrastructure to deliver services evolving nature of networks. faster and more effectively in a One networking capability that technology age that seems to grow holds particular promise for budget- As importantly for agency leaders, Segment Routing Path expressed in the packet Data ever more complex. constrained agencies—and is segment routing: gaining rapid adoption among • Segment routing architecture That complexity looms even larger large scale-network operators and • Allows agencies to reduce their seeks the right balance between Shortest path now as agencies grapple with the architects—is a routing architecture IT footprint and operating costs. distributed intelligence and mechanics of migrating various called “segment routing.” • Provides greater interoperability and centralized optimization applications and services to multicloud compatibility across new and existing environments—while also trying to The rise of segment routing networks. • Segment routing delivers an modernize their underlying networks. There’s a good reason why organizations • Offers more precise service levels for unified, end-to-end policy aware across the globe — from Walmart, to end-to-end access to applications. network infrastructure while Fortunately, the technology advances Google and Microsoft, to Bell Canada bringing unmatched simplicity that led to software-defined networking and Vodafone — are deploying segment • Provides for large-scale routing, high and scalability have also bred a new generation of routing. availability and 1-400Gb+ bandwidth. Tra c Engineered path capabilities that can simplify the • Reduces network congestion and management of hyper-converged Segment routing provides a more increases overall network efficiency. systems and multiple networks. flexible and scalable approach for • Sidesteps the risks of vendor lock-in. The upshot for federal program engineering how information travels teams: Even agencies burdened with to its intended destination. At its • Offers richer traffic-engineering legacy systems can achieve greater essence, segment routing gives capabilities that can improve mission IT performance and versatility, lower network engineers a simpler way services. Source: Cisco “From a product perspective, by pulling parts of the network, making it easier Segment Routing: Operational Advantages of Segment Routing a ton of ‘state’ and simplifying the to transport information to any part number of protocols in use, segment of the network—across multiple Where to Start

routing drastically reduces the size and domains—effectively creating a unified Segment routing can be deployed incrementally in production networks and seamlessly operate in Here are eight considerations cost of equipment agencies have to use network fabric. brownfield environments while transitioning from legacy protocols. The technology also comes with for agency decision makers and to build large transport systems,” said network designers in getting a set of functionalities that can monitor and improve overall network and service resiliency. Dorman. “It also simplifies operations— Microsoft’s Senior Software Engineer started with segment routing (SR): Among other capabilities, segment routing delivers: agency networks can become simpler Paul Mattes summed up the role to use, and run on smaller, cheaper segment routing plays in the context 1. Engage operation teams in Stateless operation Seamless deployment Unified forwarding plane platforms.” of SD-WAN architecture in a Cisco assessing the technological and Segment routing eliminates SR runs natively on an MPLS SR can create inter-domain white paper saying: “We don’t need operational pain points of current the need to create forwarding or IPv6 data plane; but it can transport policies while keeping Beyond SD-WAN to write our proprietary agent for IP/MPLS and IPV6 networks By optimizing the protocols, segment every box we want to buy. Segment state instructions in the network, coexist with existing, legacy local and wide area networks routing now makes it possible to routing lets you program only the edge. Understand the different use drastically reducing equipment LDP networks, making migration independent. 2. deploy a variety of powerful network We don’t have the problem of tunnel cases SR targets and address and operational costs. painless. capabilities, that targets a different setup synchronization; the network those challenges first. Rich functionality set of business and technology trends configures itself.” SR facilitates a wide range of Robust scalability Automated steering than those in SD-WAN. 3. For brownfield environments, SR eliminates path signaling, SR can automatically steer traffic traffic engineering innovation, But segment routing has one other take advantage of SR’s ability to reducing network complexity along arbitrary paths, based on as well as native sub-50 “SD-WAN typically targets branch big advantage: It’s designed to work co-exist with IP/MPLS networks and constraints. SR policies, to meet low-latency millisecond convergence using offices but doesn’t give enterprises with legacy systems, according to Hill. without having to rip-and-replace and SLA requirements. Topology Independent Loop granular end-to-end control of their existing networks. Free Alternative backup paths. networks,” explained Hill. “The ability “When segment routing was to do line-rate encryption also does not engineered, we recognized not every 4. Consider enabling SR in a smaller exist when you start talking about high network is a green field; it has to controlled domain in the network speed link security.” integrate with brownfield environments, before scaling it globally, allowing too—that is, the existing infrastructure,” experience in the technology and Scalability Segment routing, in contrast he said, said Hill. “There are mechanisms operations teams. Simplicity Scalable as the is particularly well suited for agencies native within segment routing, for Simple to operate network core does and organizations that want or need: example, that can map to a legacy 5. Assess the risks, but know SR maintain and not keep any state MPLS label distribution protocol (LDP) is a low-risk initiative because troubleshoot information allowing • Full control of their network—from backbone, allowing newer segment the primary protocols are end-to-end. the core to scale routing backbones to coexist with standards-based and can Segment • Control over quality and service existing MPLS networks.” coexist with existing networks. Routing level agreements. “People usually modernize a single Take advantage of SR’s ability • High bandwidth backbone 6. component,” observed Dorman. to control traffic forwarding capabilities—from 10Gb to 400Gb “We’re trying to get them to modernize end-to-end, either locally or Fast reroute Traffic engineering speeds. Guaranteed 50 m Complete control the whole system, having everything through an external controller • Large-scale routing and high sec. Protection in over how the operate from a single control point.” (SR Path Computational availability—“five nines” and beyond. Element). all cases: link, node, traffic is routed • Rich traffic-engineering capabilities— SLRG in distributed or centralized control granular path control. See how Cisco can help simplify and 7. Take further advantage of SR for transform your network capabilities IPV6 (SRv6) to collapse network environment Creating a unified fabric with segment routing. layers, eliminate overlays, making “What we’re seeing now is that our networks more consolidated and Network programmability enterprise customers want to build simpler to operate. SR for IPv6 (SRv6) takes a single ‘network fabric’ that touches segment routing to the next every network site they have across 8. Take additional advantage of levet by bringing network the globe and simplify their operations,” SR unified fabric capabilities, programmability said Dorman. with a single control plane such as E-VPN, to simplify end-to- Segment routing can enable that end transport across multiple by eliminating the need for running networks. Source: Cisco, ASG Research different transport protocols in different