In this post, I’m going to discuss how to configure and use SSH multiplexing. This is yet another aspect of Secure Shell (SSH), the “Swiss Army knife” for administering and managing Linux (and other UNIX-like) workloads.
Generally speaking, multiplexing is the ability to carry multiple signals over a single connection (see this Wikipedia article for a more in-depth discussion). Similarly, SSH multiplexing is the ability to carry multiple SSH sessions over a single TCP connection. This Wikibook article goes into more detail on SSH multiplexing; in particular, I would call your attention to the table under the “Advantages of Multiplexing” to better understand the idea of multiple SSH sessions with a single TCP connection.
One of the primary advantages of using SSH multiplexing is that it speeds up certain operations that rely on or occur over SSH. For example, let’s say that you’re using SSH to regularly execute a command on a remote host. Without multiplexing, every time that command is executed your SSH client must establish a new TCP connection and a new SSH session with the remote host. With multiplexing, you can configure SSH to establish a single TCP connection that is kept alive for a specific period Continue reading
Welcome to Technology Short Take #57. I hope you find something useful here!
Vagrantfile
and turns up the environment. Parts 4 and 5 walk through auto-configured OSPF and manually-configured OSPF, respectively. I’m looking forward to more posts in this series!Blue Planet did add two new Tier 1 customers in late 2015.
Citrix outlines a joint solution with Cisco that provides a flexible way to link network services to applications, improving security, and accelerating application deployment.
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HTTP/2 changes the way web developers optimize their websites. In HTTP/1.1, it’s become common practice to eek out an extra 5% of page load speed by hacking away at your TCP connections and HTTP requests with techniques like spriting, inlining, domain sharding, and concatenation.
Life’s a little bit easier in HTTP/2. It gives the typical website a 30% performance gain without a complicated build and deploy process. In this article, we’ll discuss the new best practices for website optimization in HTTP/2.
Most of the website optimization techniques in HTTP/1.1 revolved around minimizing the number of HTTP requests to an origin server. A browser can only open a limited number of simultaneous TCP connections to an origin, and downloading assets over each of those connections is a serial process: the response for one asset has to be returned before the next one can be sent. This is called head-of-line blocking.
As a result, web developers began squeezing as many assets as they could into a single connection and finding other ways to trick browsers into avoiding head-of-line blocking. In HTTP/2, some of these practices can actually hurt page load times.
Nuno wrote an interesting comment to my Stretched Firewalls across L3 DCI blog post:
You're an old school, disciplined networking leader that architects networks based on rock-solid, time-tested designs. But it seems that the prevailing fashion in network design and availability go against your traditional design principles: inter-site firewall clustering, inter-site vMotion, DCI, etc.
Not so fast, my young padawan.
Let’s define prevailing fashion first. You might define it as Kool-Aid id peddled by snake oil salesmen or cool network designs by people who know what they’re doing. If we stick with the first definition, you’re absolutely right.
Now let’s look at the second camp: how people who know what they’re doing build their network (Amazon VPC, Microsoft Azure or Bing, Google, Facebook, a number of other large-scale networks). You’ll find L3 down to ToR switch (or even virtual switch), and absolutely no inter-site vMotion or clustering – because they don’t want to bet their service, ads or likes on the whims of technology that was designed to emulate thick yellow cable.
Want to know how to design an application to work over a stable network? Watch my Designing Active-Active and Disaster Recovery Data Centers webinar.
This isn't the first Continue reading
VeloCloud finds a better use for extra VoIP lines.