Cloud Computing

Common Database Infrastructure in Cisco IOS XE Software Simplifies 160+ Enterprise Devices

January 26, 2023

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Developed by a worldwide group of greater than 3000 software program engineers, Cisco IOS XE Software powers greater than 160 Cisco enterprise platforms for entry, distribution, core, WAN, and wi-fi — with many alternative type components and combos of {hardware} and software program. One of the primary causes the software program stack can embody such a big portfolio of enterprise networking merchandise is because of a standard database and database-centric programming mannequin throughout all platforms.

It began with the Cisco 1000 Series Aggregation Services Router (ASR 1000) in 2004, the place each state replace to the information path went into and out of an in-memory database. Since 2015 and Cisco IOS XE model 16.1.1, many extra platforms have been added, due largely to the software program stack’s consolidated database options that work throughout all platforms. From one platform supported by IOS XE to 160 in six years is an unbelievable business run fee.

Here are a number of the most helpful and strong database options used throughout all Cisco gadgets that run Cisco IOS XE.

In-memory Database Power and Capturing Application Intent

Configuration and operational knowledge in IOS XE gadgets are saved in in-memory NoSQL graph databases. In addition to offering atomicity, consistency, isolation, and sturdiness (ACID) performance, IOS XE helps validation and default values, dependency administration, replication, notifications, subscriptions, and consolidation.

Application database intent ― together with schema, defaults, validation, and graph mannequin ― are captured in a Domain Specific Language (DSL) referred to as The Definition Language (TDL) that was developed by Cisco. Using TDL, builders can describe what they wish to do, what knowledge they wish to mannequin, and the foundations for validation. Then the TDL compiler generates database interplay code within the language of alternative for the appliance (e.g., C, Java, Python), as proven in Figure 1. If builders wish to use a brand new language, they’ll nonetheless use the intent captured in TDL to generate code.

Figure 1. Utilizing DSL to Capture Database User Intent

Decoupling intent from implementation code gives large architectural flexibility. For IOS XE, the again finish is written in C to offer optimum efficiency. The entrance finish makes use of a proper question system and could be in any language. We use a customized compiler with a Model-View-Controller (MVC)-based structure to carry out the magic of changing intent to front-end APIs.

This strategy eliminates the necessity for knowledge conversion for shoppers querying the database. As proven in Figure 2, purposes can natively work together with the database by means of APIs whatever the language of alternative. The database can be learn by different purposes and/or infrastructure (e.g., Web UI, CLI-based present instructions, and different monitoring providers).

Figure 2. Cisco IOS XE Applications Natively Interact with the Database

Runtime Infrastructure for Cisco IOS XE

Although the database infrastructure in IOS XE can use secondary storage because the database retailer, a lot of the purposes use in-memory databases that reside in RAM. A transactional engine specifies ACID ensures (e.g., a course of launched by some consumer should request modifying the database and sign when it’s achieved modifying it). Failure to finish the method leads to the database being rolled again so it’s by no means in an inconsistent state.

The uncooked lookup knowledge construction layer contains the infrastructure for indexing algorithm tables (e.g., hash tables, binary search bushes). The graph layer is the place user-specific database configurations like desk connections, default values, and validation enforcement are carried out. For instance, a Wireless Lan Controller (WLC) tracks Access Points (AP) and shoppers related to it. Clients are related to the WLC by means of the AP. This wi-fi operational state could also be modeled as AP and shopper tables, with every report within the AP desk related to a shopper desk. It is essential to notice that is the inner state of the appliance. With IOS XE database runtime, this state can now be consolidated, exported, replicated for SSO, etcetera, whereas being performant sufficient to assist the high-scale necessities for wi-fi.

Other Functions Enhanced with IOS XE Database Features

Fast reload – On reload, a persistent, version-aware, binary configuration could be learn sooner than any textual content illustration. In the previous, reloading software program on Cisco platforms might take as much as 7 minutes. With Extended Fast Software Upgrade (xFSU), it takes 30 seconds or much less. The {hardware} is rarely powered off and visitors retains flowing whereas the management aircraft is maintained in an operational state throughout the reload course of.
Stateful Process Restart – Externalizing an IOS XE machine’s configuration and operational state permits stateful restart processes. By saving the machine’s state externally, it may be restarted and can proceed the place it left off.
Horizontal Scaling – Consolidation of a tool’s operational state permits for the elastic and horizontal scaling of processes based mostly on altering software visitors patterns. There could also be a number of copies of the identical course of, every with its personal database, however Cisco permits databases to be consolidated right into a single database, offering a worldwide view, which makes it simpler to spawn extra processes horizontally.
Stateful Switchover (SSO) – Databases on lively and standby gadgets in a excessive availability configuration are repeatedly synchronized by means of replication to maintain the standby machine in a sizzling state, in a position to turn into lively in case of a failure. Like stateful course of restart, on the machine stage, SSO synchronizes one machine by means of replication repeatedly.
In-Service Software Upgrade (ISSU) – To make sure that variations of Cisco IOS XE which are operating are appropriate throughout supervisor engines and different gadgets, databases in Cisco IOS present per-object versioning assist with construct time checking for violations. This helps guarantee a dependable ISSU. ISSU orchestrates the improve on standby and lively processors one after the opposite and then switches between them within the management aircraft so that there’s zero efficient downtime and 0 visitors loss.
Monitoring and Global Device View – A tool operating IOS XE present a worldwide view of its complicated and diversified operations, based mostly on the consolidation of databases, which permits for better real-time insights into configuration and operational knowledge. Analysts can subscribe to particular knowledge units and request to be alerted when any modifications happen to watch the machine extra proactively.

Summary of Database Benefits in Cisco IOS XE

Database options in Cisco IOS XE enable gadgets to be reloaded in seconds, to take care of a state throughout restart and switchover. Applications can devour database information natively with none translation required. Intent could be gathered and code generated in any growth language, guaranteeing resilience to regressions. Databases utilized by every machine are consolidated into a worldwide view, enabling the horizontal scaling of processes. The system helps model skew operation with per-object versioning.

It’s all comparatively seamless throughout all 160+ Cisco IOS XE gadgets.