New XR Programmability Learning Labs and Sandbox Let You Explore

Turning team focus to network automation and programmability

I came from a network service provider background. Then, when I starting working at Cisco, I was working on the Cisco Security network team. The global network we built, owned, and managed was much like a service provider network. We had lots of transit links, and circuits with service providers, and tons of peering links, and sessions all over the world. Managing this was a full-time job, and I am just talking about managing the WAN (wide area network) here. Which is why, like many of you and other network teams out there whose network requires speed, scale, and data analytics, my team and I turned our focus to network automation and programmability.

The majority of our network devices (both core and edge) were running IOS XR. IOS XR has always been one of my favorite platforms, so it was with great excitement that when I began working for the Cisco DevNet team, my specialist area would be working with the IOS XR teams and platform.

What is new to learn here?

A great question, I am pleased you asked! We have built a dedicated sandbox environment for IOS XR programmability and learning labs to go with this.  The IOS XR Programmability sandbox and learning labs provide an environment where developers and network engineers can explore the programmability options available in this routing platform. These include:

◈ Model Driven Programmability with YANG Data Models, NETCONF and gRPC
◈ Streaming Telemetry
◈ Service-Layer APIs
◈ Application Hosting

What gear can you access in the sandbox?

We wanted to build a sandbox that provides the right level of simplicity for users to get started while offering a flexible platform they can build on. The sandbox provides two Cisco IOS XRv 9000 devices (R1 and R2) connected back to back, plus a Linux host that acts as a development box (DevBox). The image version on Sandbox tile is 6.4.1 this is available on both the two IOS-XR nodes.

The new IOS XR programmability sandbox lets you explore programmability options available in this routing platform.

The all-new learning labs and track

You can use the IOS-XR programmability learning track to familiarize yourself with the rich set of programmable interfaces and APIs offered by IOS-XR. The goal of this track is to introduce you to the architectural tenets of the IOS-XR network stack and showcase how APIs at every layer of the stack – from Manageability APIs like YANG models, CLI, ZTP hooks to Service Layer APIs at the network infrastructure layer can be used to completely transform the way you manage and provision your network.

◈ IOS-XR CLI automation Cisco IOS-XR offers a comprehensive portfolio of APIs at every layer of the network stack, allowing users to leverage automated techniques to provision and manage the lifecycle of a network device. In this module, we start with the basics: the Command Line Interface (CLI) has been the interaction point for expect-style scripters (TCL, expect, pexpect etc.) for ages; but these techniques relying on send/receive buffers are prone to errors and inefficient code. This is where the new onbox ZTP libraries come handy. Use them for automated device bring-up or to automate Day1 and Day2 behavior of the device through deterministic APIs and return values in a rich Linux environment on the router.

◈ IOS-XR Model-Driven Automation: YANG models Cisco IOS-XR offers a comprehensive portfolio of APIs at every layer of the network stack, allowing users to leverage automated techniques to provision and manage the lifecycle of a network device. APIs that are derived, documented and versioned using deterministic models are contractually obliged to match the expectations laid out by the model. Following this ethos, in IOS-XR, all the capabilities of the software, traditionally offered through the Command Line Interface (configuration commands, show commands, exec commands) are mapped to equivalent Config and Oper YANG models backed by the internal IOS-XR Database called SYSDB. In this module, we start taking the first steps towards model-driven programmability as we dive deeper into IOS-XR Yang models. We look at the interaction with these models with tools such as ncclient, YDK or gRPC clients and tips to map your CLI configurations to corresponding YANG-Modeled XML/JSON representations.

◈ IOS-XR Streaming Telemetry: SNMP is dead! It is time to move away from slow, polling techniques employed by SNMP for monitoring that are unable to meet the cadence or scale requirements associated with modern networks. Further, Automation is often misunderstood to be a one-way street of imperative (or higher-layer declarative) commands that help bring a network to an intended state. However, a core aspect of automation is the ability to monitor real-time state of a system during and post the automation process to accomplish a feedback loop that helps make your automation framework more robust and accurate across varied circumstances. In this module, we learn how Streaming Telemetry capabilities in IOS-XR are all set to change network monitoring for the better – allowing tools to subscribe to structured data, contractually obliged to the YANG models representing operational state of the IOS-XR internal database (SYSDB) at a cadence and scale that are orders of magnitude higher than SNMP.

◈ IOS-XR Service-Layer APIs: Cisco IOS-XR offers a comprehensive portfolio of APIs at every layer of the network stack. For most automation use cases, the manageability layer that provides the CLI, YANG models and Streaming Telemetry capabilities, is adequate. However, over the last few years, we have seen a growing reliance in web-scale and large-scale Service Provider networks on off-box Controllers or on-box agents that extract away the state machine of a traditional protocol or feature and marry their operation to the requirements of a specific set of applications on the network. These agents/controllers require highly performant access to the lowest layer of the network stack called the Service Layer and the model-driven APIs built at this layer are called the Service-Layer APIs. With the ability to interact with RIB, the Label Switch Database (LSD), BFD events, interface events and more capabilities coming in the future, it is time to take your automation chops to the next level.

The sandbox provides two Cisco IOS XRv 9000 devices (R1 and R2) connected back to back, plus a Linux host that acts as a development box (DevBox).

Getting Started

The development box includes a “hello world” sample app to check the uptime on routers to get you started.

hello-ydk.py

The script illustrates a minimalistic app that prints the uptime of a device running Cisco IOS XR. The script opens a NETCONF session to a device via the devices IP address, reads the system time and prints the formatted uptime.

Sample Output: