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Data Center Replication: WAN Optimization vs. Bandwidth Upgrade

During the past years WAN optimization devices were used to optimize end-user traffic mainly. Employers connecting to remote applications can achieve better user experience if a couple of WAN optimization are deployed. Typically web applications, file sharing and email can be well accelerated: end users can increase their productivity with a little investment.

On the other side providers usually offer free bandwidth upgrade during a contract renewal.

So the question are:

  • Can Data Center replication take advantage of WAN optimization?
  • Can a Bandwidth upgrade always supersede WAN optimization?

The answers are, as always: it depends. Read More »

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Ain’t your father’s TCP

February 15, 2013 at 5:00 am PST

TCP?  Who cares about TCP in HPC?

More and more people, actually.  With the commoditization of HPC, lots of newbie HPC users are intimidated by special, one-off, traditional HPC types of networks and opt for the simplicity and universality of Ethernet.

And it turns out that TCP doesn’t suck nearly as much as most (HPC) people think, particularly on modern servers, Ethernet fabrics, and powerful Ethernet NICs.

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Student project collaboration with NC State University

It was about a year ago that Dr. Yannis Viniotis, Professor of the Electrical & Computer Engineering (ECE) department at North Carolina State University (NCSU), met with senior Cisco Engineers and agreed to collaborate on several small, hands-on projects with Cisco Engineers and NCSU students.

The NCSU ECE department partners with the industry as part of their Senior Design Project Program, where various vendors serve as sponsors and offer several projects for NCSU students to complete. That is also how the Cisco-NCSU collaboration started. Students get to work on real networking industry problems guided by engineers that already work in the industry. The students gain experience that can be later used in their professional lives. The Cisco engineers get to work with future engineers, mentoring and preparing them for their professional lives and solving some real world technical challenges. It is fun and educational for both sides.

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The Maginot Line and the TCP Sequence Number Inference Attack

In the recently posted research paper “Off-Path TCP Sequence Number Inference Attack: How Firewall Middleboxes Reduce Security“, Zhiyun Qian and Z. Morley Mao from the University of Michigan discuss a method to try to infer the sequence numbers in use by a TCP connection -- and if successful, how to try to hijack the connection and inject data on it in order to, as an example, steal credentials to web sites (banking, social networking, etc.)

Before talking further about their research, I would like to talk a bit about the Maginot Line. The Maginot Line was a line of fortifications located in France, established after World War I, and roughly following France’s borders with Germany and Italy. The idea behind it: in case of another war with Germany, the line would hold the enemy attacks, giving the French Army the chance to regroup and counterattack. The problem: the line only extended so far up North. So during World War II, and instead of attacking the line from the East, the German army completely bypassed it – by attacking Belgium first and then flanking the line.

So a lot of resources were allocated to set-up defenses for a very specific attack scenario – but that scenario never happened, as an easier way was found to bypass the defenses. And the mere fact of allocating so many resources to counter a specific threat significantly reduced the number of resources available to protect against other threats.

The method posited by Qian and Mao on their research paper strongly reminds me of the assumptions made by the French while building the Maginot Line.

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