“We have built more edge locations than even Amazon has done in the United States,” CTO Tareq...
“We have built more edge locations than even Amazon has done in the United States,” CTO Tareq...
SDxCentral Weekly Wrap for Nov. 8, 2019: Security and SD-WAN are Fortinet’s focus; Amazon is...
The company cited simplicity and security as being the heart of its K10 platform in order to target...
You may have noticed last week that Ubiquiti added a new “feature” to their devices in a firmware updated. According to this YouTube video from @TomLawrenceTech, Ubiquiti built an new service that contacts a URL to “phone home” and check in with their servers. It got some heavy discussion going, especially on Reddit.
The consensus is that Ubiquiti screwed up here by not informing people they were adding the feature up front and also not allowing users to opt-out initially. The support people at Ubiquiti even posted a quick workaround of blocking the URL at a perimeter firewall to prevent the communications until they could patch in the option to opt-out. If this was an isolated incident I could see some manner of outcry about it, but the fact of the matter is that companies are adding these hidden features more and more every day.
The first issue comes from the fact that most release notes for apps any more are nothing aside from platitudes. “Hey, we fixed some bugs and stuff so turn on automatic updates so you get the best version of our stuff!” is somewhat common now when it comes to a list of Continue reading
Showing the path helps you walk it
The post Rita Younger – Believe in Yourself, Technical Woman appeared first on EtherealMind.
Now it’s time to put it all together.
It’s been a while since we looked a debugging and troubleshooting on The Morning Paper (here’s a sample of earlier posts on the topic). Today’s paper introduces a root cause of failure detector for those hard-to-pin-down bugs. Whereas most root cause analysis systems start from the failure and work backwards, Kairux starts from the beginning of the program execution and works forwards. It’s based on the simple idea that the root cause is likely to be found where the failing execution deviates from successful executions.
If we model an execution as a totally ordered sequence of instructions, then the root cause can be identified by the first instruction where the failure execution deviates from the non-failure execution that has the longest instruction sequence prefix in common with that of the failure execution.
This point where the failing run deviates from the longest successful instruction sequence prefix is called the inflection point, and the Inflection Point Hypothesis says that the inflection point is likely to be the root cause.
The definition of root cause itself is taken from Continue reading
DMZ Anywhere Architecture – Webinar
In this webinar Orhan Ergun and Ahmed Al-Deeb are talking about DMZ Anywhere architecture. Micro Segmentation , Deploying DMZ in a virtual environment to reduce cost, providing flexibility and better performance will be highlighted.
Mobile Broadband Basics – Webinar
In this webinar Orhan Ergun and Karim Rabie is talking about Mobile broadband technologies basics. 2G, 3G,4G,LTE and 5G is explained by Mobile Broadband expert Karim Rabie.
Sessions slides will be uploaded shortly.Introduction to Mobile Broadband- 2G, 3G, 4G, LTE and 5G Technology basics
Global CCDE List
How many CCDEs are there in the world? What country has the most CCDEs? How do you become a CCDE Global List member? You can find out the answers to these questions below. If you have a CCDE number, if you changed your country or company share it in the comment box below or contact me directly. This list will be updated as soon as new members are accredited. You can be the one of them.More than 60 of these CCDEs passed the exam after Orhan Ergun’s CCDE bootcamp.
Total Number of CCDE: 430
|Top Companies||Top Countries||Lady CCDE (4 CCDE)|
|Cisco (94 CCDE)||U.S (105 CCDE)||Denise Fishburne|
|Conscia (8 CCDE)||U.K (22 CCDE)||Louise Simmons|
|AT&T (5 CCDE)||Germany (13 CCDE)||Lauren Child|
|Dimension Data (4 CCDE)||UAE (11 CCDE)||Irene Salas|
|VMware (4 CCDE)||Australia (9 CCDE)|
GLOBAL CCDE LIST
4 Main, Key Design Principles of Mobile Networks – I will explain the 4 key design principles of cellular networks in plain English.
In fact I should have said, cell based systems as mobile networks may not be design based on cell based architecture.
Let me explain what would be the other deployment option for the mobile network, other than cell based systems and then will highlight the 4 main characteristics of cell based mobile networks.
Before, cellular systems designed, mobile network operators used to place their radio transmitters at the tallest buildings in the area which they want to provide a coverage. Single, very high-power transmitters was used to cover very large geographic areas.
With the cell based telephone systems, so many low-power, small coverage area transmitters are used instead of a single, powerful, monolithic transmitter to cover a wide area.
This is first design principles of cell based mobile phone networks.
Second design principle of cell based systems is frequency reuse.
I hared a post on wireless frequency spectrum allocation problem here. Read it as well, if you want to understand the limit and the problems of electromagnetic frequency spectrum.
The second design principle which is frequency reuse, takes Continue reading
The MANET stands for mobile ad hoc network; in practice, the term generally applies to ad hoc wireless networks of sufficient complexity that some internal routing mechanism is needed to enable full connectivity.
The term mesh network is also used for MANETs.
MANET nodes communicate by radio signals with a finite range, as in the Figure – 1 below.
Each node’s radio range is represented by a circle centered about that node. In general, two MANET nodes
may be able to communicate only by relaying packets through intermediate nodes, as is the case for nodes
A and G in the diagram above.
Mobile Ad Hoc networks can use any wireless mechanism
In the field, the radio range of each node may not be very circular, due to signal reflection. An additional complication arises when the nodes (or even just obstructions) are moving in real time (hence the “mobile” of MANET); this means that a working route may stop working a short time later.
For this reason, routing within MANETs is a good deal more complex than routing in an Ethernet. A switched Ethernet, for example, is required to be loop-free, so there is never a choice among multiple alternative routes.
MANETs in general do not support broadcast, Continue reading
Wireless ISPs also known as WISP mostly use unlicensed frequency spectrum. Frequency spectrum is the most critical asset for the Mobile and Wireless networks and it is sold in auctions for 100s of millions of dollars.
Frequency spectrum is managed by the governments and governments in general, sell frequency spectrum in auctions.
And some frequencies are really expensive, I am talking about 100s of millions of dollars. But frequency spectrum is so important ? Why it is a problem with Wireless Internet Service Providers ? What is Wireless Internet Service Provider in the first place ? I explain all these questions during my Telecom Training but I wanted to share below post with you.
Below you will find a very nice write up from one of the founding members of the Wireless Internet Service Providers Association (WISPA).
Although it is written for the U.S government, situation is the same in every country for the Wireless Internet Service Providers.
Congress – Stop Selling Our Airwaves!
by John Scrivner
Do you have little or no access to broadband (high speed) Internet? Then forward this note to your Congressman to get this fixed.
Broadband is something most Americans take for granted. That is unless Continue reading
GRE tunnels are by far most common tunnelling technology. Very easy to setup, troubleshoot and operate. But in large scale deployment, configuring GRE tunnels become cumbersome, because GRE tunnel is a point to point tunnel.
GRE Tunnel Characteristics
• GRE tunnels are manual point to point tunnels. Tunnel end points are not automatically derived. Network operator needs to configure the tunnel end points manually.
• Supports routing protocols to run over. You can run any routing protocols on top of GRE tunnels.
• IPv4 and IPv6 can be transported over GRE. Some VPN technologies may not support IPv6 or IPv6 routing protocols.
• Non-IP protocols such as IPX, SNA etc. can be carried over GRE tunnel as well. Most of the tunnelling technologies cannot carry Non- IP traffic. For example, IPSEC tunnel cannot carry Non-IP Traffic.
• If there are too many sites that need to communicate with each other, GRE is not scalable. But in Hub and Spoke topologies it can be used since whenever new spoke site is added, only new site and hub should be revisited. Not all the spokes need configuration.
• Even though in Hub and Spoke topologies, the configuration can be too long on the Continue reading
Introduction to VPN (Virtual Private Network)
Let’s start with the definition. VPN is a logical network and created over shared physical infrastructure.
Shared infrastructure can be private such as MPLS VPN of a Service Provider or over the Public infrastructure such as Internet.
There are many concepts to understand VPN in detail but in this article I will cover the definition, common design considerations, and some not well known concepts about it.
We can group VPNs into two categories. WAN and the Datacenter VPN Technologies.
WAN VPN Technologies
2.mGRE (Multipoint GRE)
8. MPLS L3 VPN
Datacenter VPN Technologies
1.EoMPLS (Ethernet over MPLS (a.k.a VPWS)
2. VPLS (Virtual Private Lan Service)
3. OTV (Overlay Transport Virtualization)
6. VXLAN (And other host based overlays such as NVGRE, STT, GENEVE)
Of course this is not the complete list. Please note that some of the technologies which I grouped into WAN technologies can be used in the Datacenter and vice versa.
For example LISP can be used in Datacenter as well and VPWS and VPLS can be used on the Wide Area Network as well.
Should I use Cisco OTV for the Datacenter Interconnect? This question comes from not only from my students but also the companies which I provide consultancy.
I will not go through the OTV details, how it works, design recommendations etc. But let me remind you what is OTV and why OTV is used , Where it makes sense very briefly.
OTV (Overlay Transport Virtualization) is a tunnelling mechanism which provides to carry Layer 2 ethernet frame in IP. (As I indicated in other articles, when I say MAC in IP, it is the same thing with MAC over IP).
So, OTV is Layer 2 in Layer 3 tunnelling mechanism. You can hear it is an encapsulation mechanism as well, which is true although there is small difference.
You don’t need to have MPLS underlay to create OTV tunnels. It uses IS-IS for the MAC address reachability and stops layer 2 protocol PDUs at the OTV Edge device where encapsulation happens.
This is good because, you don’t want to extend Layer 2 protocol PDUs such as Spanning Tree if you have multiple datacenters. Failure stays and affects only one datacenter, not all. (Failure domain boundary concept)
Another datacenter interconnect requirement Continue reading