I will be speaking at NANOG on the road tomorrow—the topic is “An Introduction to Network Complexity.” If you’re in the Raleigh area, this is well worth taking the time off to come to, as the speaker lineup is fantastic.
The post Introduction to Network Complexity at NANOG on the Road appeared first on 'net work.
No one really like serial numbers, but keeping track of them is one of the “brushing your teeth” activities that everyone needs to take care of. It’s like eating your brussel sprouts. Or listening to your mom. You’re just better of if you do it quickly as it just gets more painful over time.
Not only is it just good hygene, but you may be subject to regulations, like eRate in the United States where you have to be able to report on the location of any device by serial number at any point in time.
Trust me, having to play hide-and-go seek with an SSH session is not something you want to do when government auditors are looking for answers.
I’m sure you’ve already guessed what I’m about to say, but I”ll say it anyway…
There’s an API for that!!!
HPE IMC base platform has a great network assets function that automatically gathers all the details of your various devices, assuming of course they supportRFC 4133, otherwise known as the Entity MIB. On the bright side, most vendors have chosen to support this standards based MIB, so chances are you’re in good shape.
And if they don’t Continue reading
An analogous observation that readers may be familiar with is the importance of minimizing costs when investing in order to maximize returns - see Vanguard Principle 3: Minimize costSuppose that a 100 server pool is being monitored and visibility will allow the orchestration system to realize a 10% improvement by better workload scheduling and placement - increasing the pool's capacity by 10% without the need to add an additional 10 servers and saving the associated CAPEX/OPEX costs.
Some time ago we discovered that certain very slow downloads were getting abruptly terminated and began investigating whether that was a client (i.e. web browser) or server (i.e. us) problem.
Some users were unable to download a binary file a few megabytes in length. The story was simple—the download connection was abruptly terminated even though the file was in the process of being downloaded. After a brief investigation we confirmed the problem: somewhere in our stack there was a bug.
Describing the problem was simple, reproducing the problem was easy with a single curl command, but fixing it took surprising amount of effort.
CC BY 2.0 image by jojo nicdao
In this article I'll describe the symptoms we saw, how we reproduced it and how we fixed it. Hopefully, by sharing our experiences we will save others from the tedious debugging we went through.
Two things caught our attention in the bug report. First, only users on mobile phones were experiencing the problem. Second, the asset causing issues—a binary file—was pretty large, at around 30MB.
After a fruitful session with tcpdump one of our engineers was able to prepare a test case that reproduced the Continue reading