LSA issue @ January 28, 2017 at 02:35PM

A burden of many #NETCONF articles and tutorials is that they are often silent about the #YANG part. This is why we would like to highlight this post by Michael Kashin called ""Getting Started With NETCONF and YANG"" [1]. Not only this article covers the basics of network elements configuration via NETCONF (particularly via python ncclient module [2]) but also extends to the YANG models definition with practical examples.

Michael uncovers how heavily NETCONF relies on YANG models, how one can download models straight from a network element itself and how to repsent YANG models in a human-readable tree-view with pyang [3] support.

In its closing you'll see a little bit more advanced technique of building a python module based on the downloaded YANG models. Later this python module is used to create a configuration XML delivered via NETCONF to the network element resulting in a configuration change.

And if you are intereseted in NETCONF, make sure to check a NETCONF package for ATOM [4] which allows you easily compose and deliver NETCONF commands to the network elements and the Yang-Explorer tool to visually examine YANG models [5]

#Article #Automation #NETCONF #YANG

[1] http://ift.tt/2kEkgdn
[2] http://ift.tt/2kDS85X
[3] http://ift.tt/2bBSXwI
[4] http://ift.tt/28Z8gKx
[5] http://ift.tt/2kElsxf
By: via LSA

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NokDoc Library & NokDoc CLI Tool

featured

For many years Alcatel-Lucent’s documentation was all about authorized personnel only. All of it. And not so long ago ALU opened a considerable part of its documentation portfolio to everyone via its support portal!

This portal internally is the same support portal available at alcatel-lucent.com domain though styles are now aligned with Nokia brand-kit. And being the same means that it is often slow in response, old-fashioned in UI and demands too much clicks and scrolling from you.

I hope that one day our documentation portal will be redesigned from ground up in a way that it would match current UX/UI patterns. In the meantime I took a humble attempt to make it a little bit more engineer-friendly.

That’s how I ended up with two projects:

  • Web library with direct links to Nokia’ product documentation — NokDoc Lib
  • And the CLI tool to fetch links to documentation and download it — NokDoc CLI Tool

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LSA issue @ January 23, 2017 at 10:41AM

It is always tempting and interesting to see how big guys do their networks. We saw some pieces from Google, Facebook, Amazon, LinkedIn and now Twitter comes. Big 5 is all set!

Last week engineering force at Twitter released an article titled ""The Infrastructure Behind Twitter: Scale"" [1]. The article starts off with networking field in focus and covers both DC and Backbone challenges Twitter faced over the time.

Data Center story is no surprise at all, IGP started to give more troubles that benefits and was swapped with ""BGP as IGP"" solution. Classics of modern DC design. By the way, there is a bonus track in the DC section of the article — a nice slide deck explaining how Twitter did this migration on a live network [2].

At the Backbone side Twitter surpisingly had no TE at some point (o.O). Now they most certainly do and they also adopted TE++ from Juniper [3] which helps them overcome bin-packet problem (common problem for Big 5, Facebook had this as well). After all RSVP-TE autobandwith has some serious players that have implemented it.

When it comes to Edge, problems like PoP design and steering traffic to PoPs start to pop out. Serving a customer from a closest point available (less RTT means less delay and more goodput) is a corner stone for worldwide scale players. On the latter case Twitter ditched geo-DNS in favor of BGP-anycast. We saw this done by LinkedIn and Facebook [4],[5]

Though from a birds eye view all the probles are the same we should thank Twitter for sharing! Maybe we'll see more goodnes from their Engineering dept. soon.

#Article #Datacenter #RSVPTE #BGP

[1] https://blog.twitter.com/2017/the-infrastructure-behind-twitter-scale

[2] http://ift.tt/2iXOVjR

[3] http://ift.tt/2iXSNBg

[4] https://www.youtube.com/watch?v=LPCbKzhvAGc

[5] http://ift.tt/2jnKpsp
By: via LSA

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LSA issue @ January 19, 2017 at 10:43AM

Here is the question: if Host A wants to transmit some data across TCP/IP network to Host B with IP address of 1.2.3.4 how will this Dest_IP address be represented?

Correct, it will be hex encoded, but will the bytestream be like 0x01 02 03 04 or 0x04 03 02 01? Yep, you see where I am going, its endianness who is telling us which byte comes first.

So take a look at this short article which is a perfect read on Endianness. It uncovers why x86 CPUs (back in 90-00's) were a bad choice for networking equipment and how the hell Gulliver's Travels has mixed up with all of it?

#Article #TCP

http://ift.tt/2k2Q6vX
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Yang Explorer in a Docker container

yang_exp_featured

I would like to see a day come true where all major vendors’ boxes (even small & cheap ones) will be 100% covered by YANG models. Can’t say I believe that it is possible for IETF to standard all the things in vendors domain, but we will manage as long as vendors will stick to standard YANG in their own in-house data modes.

Being in shadows for quite some time, Netconf/Yang are still something new to explore for many of network engineers, myself included. And that’s todays topic — exploring YANG data models with Yang Explorer tool in a docker container (reads: without pain).

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LSA issue @ January 1, 2017 at 02:13PM

Hey there, engineers! Its January 1st 2017 and we are happy to welcome you and wish you all the best.
But is it 2017 indeed? How would one tell if his clock is good, if its in sync with the world clock? Yeah, you got it, in the era of the leap second and New Year eve what topic could we bring up if not NTP?

Lucky us, an Australian SRE@Canonical Paul Gear wrote a 5-post long topic called ""The School for Sysadmins Who Can’t Timesync Good and Wanna Learn To Do Other Stuff Good Too"". We bet you'll become grandmaster of NTP once you read all five of them!

#Article #NTP #Synchronization

Part 1 — The problem with NTP: http://ift.tt/2ivmx9b

Part 2 — How NTP works: http://ift.tt/2iSgk3y

Part 3 — NTP install and configure: http://ift.tt/2ivnUVu

Part 4 — Monitoring and Troubleshooting: http://ift.tt/2iSlPiN

Part 5 — Myths, misconception and best practices: http://ift.tt/2ivmwC9
By: via LSA

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