BRKARC-3300 – IOS-XE: Enabling the Digital Network Architecture

Presented by Muhammad A Imam, Sr Manager Technical Marketing Engineering

Brand new session!

The goal of the session is to give an understanding of IOS-XE Denali 16.x.

How many have downloaded 16.x?” — maybe 10% put up their hands

The upcoming 16.3 (target for this month) will support Cat 3850,3650, ISR, and ASR 1000.

The original operating system on the AGS, back in 1986, was simply called “Operating System”. There are still parts of Operating System in IOS today (scary!!).

IOS-XE (code name BinOS) came around in 2007 on the ASR 1000. In 2010, IOS-XE (code name Nova) was released for the Cat4k. These two editions of XE were similar, but different and were written by different engineering teams.

The vision for IOS-XE Denali is a single code base across Cisco enterprise platforms. Benefits include: similar features, consistent version numbers, consistent release schedule, consistent test and validation of releases, consistent commands (eg “show platform …”).

“We are changing the way we write code” –Muhammad; code is being pulled out of the IOSd blob and written as a subsystem within IOS-XE (over time).

Crimson database:

  • New component in Denali
  • Maintains state for subsystems
  • Holds configuration
  • Centralized point of inter-process communication (instead of all processes being able to speak with all other processes)
  • Goal is to have everything fully “Crimsonized” by release 16.5
  • Separates code from data; executing code doesn’t hold the authoritative copy of data/config/state; that lives in the db. A code failure/defect, doesn’t affect the data.
  • Databases can be replicated . Think of HA. Think of replication to a controller. 😁
  • YANG data model is on the roadmap to allow third-party access to the Crimson db contents (target for release 16.3)

Stackwise Virtual:

  • Addresses the issue with the C3850-48 SFP+ that does not have stack capability (stack ports are not present)
  • Leverages capabilities in Denali to do stacking using the front panel ports (closer to how VSS works)
  • For now, Stackwise Virtual will only be on C3850-48 SFP+ model

Migration to Denali:

  • On Cat3k: XE 3.7 is end of the road: your next upgrade will have to be Denali
  • ASR 1000: XE 3.17 is end of the road: your next upgrade will have to be Denali

Q: Will we ever see patching in IOS-XE? (Patching subsystems rather than the whole OS)

  • That is the goal, yes. Patches will be distributed on cisco.com (like recent versions of NX-OS today)

Q: When will Cat6k move to Denali?

  • Eventually. The long-term plan is for all campus platforms to run Denali.

Q: How long does a reboot take in Denali?

  • 4 minutes and change
  • Big difference from XE 3.6/3.7 which is 10-12 minutes
  • Inside Cisco, Denali is compiled from source every night. That build is then tested to see how long it takes to boot. If the boot time goes up on that build, the most recent source code commits are examined to see what happened and the code is fixed.

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