Developed by a world workforce of greater than 3000 software program engineers, Cisco IOS XE Software program powers greater than 160 Cisco enterprise platforms for entry, distribution, core, WAN, and wi-fi — with many various kind components and combos of {hardware} and software program. One of many 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 Collection Aggregation Providers Router (ASR 1000) in 2004, the place each state replace to the info 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 unimaginable business run price.
Listed below are a number of the most helpful and sturdy database options used throughout all Cisco units that run Cisco IOS XE.
In-memory Database Energy and Capturing Software Intent
Configuration and operational information in IOS XE units are saved in in-memory NoSQL graph databases. Along with offering atomicity, consistency, isolation, and sturdiness (ACID) performance, IOS XE helps validation and default values, dependency administration, replication, notifications, subscriptions, and consolidation.
Software database intent ― together with schema, defaults, validation, and graph mannequin ― are captured in a Area Particular Language (DSL) referred to as The Definition Language (TDL) that was developed by Cisco. Utilizing TDL, builders can describe what they wish to do, what information they wish to mannequin, and the foundations for validation. Then the TDL compiler generates database interplay code within the language of selection for the applying (e.g., C, Java, Python), as proven in Determine 1. If builders wish to use a brand new language, they’ll nonetheless use the intent captured in TDL to generate code.

Decoupling intent from implementation code gives super 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 may be in any language. We use a customized compiler with a Mannequin-View-Controller (MVC)-based structure to carry out the magic of changing intent to front-end APIs.
This strategy eliminates the necessity for information conversion for shoppers querying the database. As proven in Determine 2, functions can natively work together with the database by APIs whatever the language of selection. The database may also be learn by different functions and/or infrastructure (e.g., Net UI, CLI-based present instructions, and different monitoring companies).

Runtime Infrastructure for Cisco IOS XE
Though the database infrastructure in IOS XE can use secondary storage because the database retailer, many of the functions 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 carried out 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 information construction layer contains the infrastructure for indexing algorithm tables (e.g., hash tables, binary search timber). The graph layer is the place user-specific database configurations like desk connections, default values, and validation enforcement are carried out. For instance, a Wi-fi Lan Controller (WLC) tracks Entry Factors (AP) and shoppers related to it. Purchasers are related to the WLC by the AP. This wi-fi operational state could also be modeled as AP and consumer tables, with every report within the AP desk related to a consumer desk. It is very important notice that is the interior state of the applying. With IOS XE database runtime, this state can now be consolidated, exported, replicated for SSO, etcetera, whereas being performant sufficient to help the high-scale necessities for wi-fi.
Different Features Enhanced with IOS XE Database Options
- Quick reload – On reload, a persistent, version-aware, binary configuration may be learn sooner than any textual content illustration. Prior to now, reloading software program on Cisco platforms may take as much as 7 minutes. With Prolonged Quick Software program Improve (xFSU), it takes 30 seconds or much less. The {hardware} is rarely powered off and visitors retains flowing whereas the management airplane is maintained in an operational state throughout the reload course of.
- Stateful Course of Restart – Externalizing an IOS XE system’s configuration and operational state permits stateful restart processes. By saving the system’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 primarily based on altering utility 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 world view, which makes it simpler to spawn extra processes horizontally.
- Stateful Switchover (SSO) – Databases on lively and standby units in a excessive availability configuration are constantly synchronized by replication to maintain the standby system in a sizzling state, in a position to turn into lively in case of a failure. Like stateful course of restart, on the system stage, SSO synchronizes one system by replication constantly.
- In-Service Software program Improve (ISSU) – To make sure that variations of Cisco IOS XE which can be working are right throughout supervisor engines and different units, databases in Cisco IOS present per-object versioning help 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 airplane so that there’s zero efficient downtime and 0 visitors loss.
- Monitoring and International Gadget View – A tool working IOS XE present a world view of its complicated and various operations, primarily based on the consolidation of databases, which permits for larger real-time insights into configuration and operational information. Analysts can subscribe to particular information units and request to be alerted when any adjustments happen to watch the system extra proactively.
Abstract of Database Advantages in Cisco IOS XE
Database options in Cisco IOS XE enable units to be reloaded in seconds, to keep up a state throughout restart and switchover. Functions can devour database information natively with none translation required. Intent may be gathered and code generated in any improvement language, guaranteeing resilience to regressions. Databases utilized by every system are consolidated into a world 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 units.
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Cisco Champions the Highly effective, Evolving Networking Software program Stack
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