BGP dampening – punishment for unstable BGP prefixes
How does the internet work - We know what is networking
BGP prefix flapping can be caused by different issues in network. Basically every unstable network where links are unreliably and are going up and down here and there can cause BGP prefix flapping. Every prefix flap will cause some networks to became unreachable. BGP process will then need to recalculate best-path in order to hopefully […]
Welcome to the IP address Lookup tutorial
A router’s main function is to forward an incoming packet to its destination by using routing and forwarding techniques. Forwarding can be defined as taking the incoming packet, looking at its destination IP address, consulting the forwarding table, and directing the packet to the appropriate next-hop and output link based on the information retrieved from the forwarding table. On the other hand, routing is the process by which the forwarding table itself is built. Forwarding is a relatively simple process performed locally at the router, whereas routing depends on a variety of distributed dynamic and static routing protocols.
To consult the forwarding table, the router uses the packet’s destination IP address as a key to retrieve the forwarding information (e.g., next-hop and output interface) – this operation is called IP address lookup. Once the forwarding information is available, the router transfer the packet from the incoming interface to the appropriate outgoing interface.
The greatest challenge and major bottleneck is how to make the IP address lookup fast enough to keep up with backbone routers that support high data rate interfaces (up to 10 Gbps and more). Therefore, they must be able to perform millions of address lookup operations Continue reading
The Difference Between SDN, Automation and Orchestration
An explanation of the difference between SDN, Automation and Orchestration.
The post The Difference Between SDN, Automation and Orchestration appeared first on EtherealMind.
A Short Update on CML from #CLUS
Hey everyone,
I’ve been having a really good time here at Cisco Live US. Here is a short update on CML.
General Info
CML is being released end of June or beginning of July. The corporate edition with
a base license and support for up to 15 nodes will be listed at around 13000$ per year.
If you subscribe for two years, the discount is 5% and for three years it is 10%
Normally 15 nodes cost around 13000$ per year so basically you get 5 nodes for “free”
if you get the base package which has the SKU R-CML-CE-K9=.
IOS will be supported by running IOSv. Every IOSv image requires around 512 MB of memory.
System Requirements:
- The Cisco Modeling Labs server runs on VMware ESXi 5.0, 5.1, and 5.5.
- Recommended – Cisco UCS®
- C220 M3 Rack Server with 16 core CPU and 128 GB memory or Cisco UCS
- C460 M2 High-Performance Rack Server or higher model (actual memory and CPU consumption depends
on the number of virtual nodes and virtual network OS types). To help determine the appropriate memory
please find the Cisco Modeling Labs Calculator at http://www.cisco.com/go/cml. - Following are the minimum hardware Continue reading
Renesys, Dyn Join Forces
Today, we’re announcing the acquisition of Renesys by Dyn, the leading provider of Internet Performance solutions. Dyn and Renesys represent the perfect combination of Internet Intelligence assets from Renesys and Traffic Management and Message Management solutions from Dyn. We’re excited to become part of the Dyn team!
Those who know both companies may ask, “What took you so long?” Our headquarters are located blocks apart in beautiful downtown Manchester, New Hampshire, and the two founding teams have known each other for years. Dyn and Renesys share a surprising amount of cultural DNA – building scalable global infrastructure, understanding the economics and performance of the Internet at a deep technical level, and helping our customers deliver smarter, faster service worldwide.
Why Renesys? Why Dyn?
Renesys builds network performance management products for the Internet. We help enterprises tackle the strategic and operational challenges of delivering service over the public Internet, to consumers and businesses beyond the firewall. We operate a best-in-breed global Internet measurement platform, performing over a billion measurements each day to assess the Internet’s health and function. Anywhere in the world, when a decision maker needs insight into local Internet infrastructure, performance impairment, economics, competition, or strategy, we Continue reading
Response: NFV: Will vRouters ever replace hardware routers?
I'm not the only person pointing out the software routers are reaching unprecedented performance levels.
The post Response: NFV: Will vRouters ever replace hardware routers? appeared first on EtherealMind.
NFV: Will vRouters ever replace hardware routers?
When i started looking at NFV, i always imagined it being relegated to places in the network that would receive only teeny weeny amount of data traffic since the commodity hardware and software could only handle so much of traffic. I also naively believed that it would be deployed in networks where customers were not uber-sensitive to latency and delay (broadband customers, etc). So if somebody really wanted a loud bang for their buck they had to use specialized hardware to support the network function. You couldnt really use Intel x86-based servers running SW serving customers for whom QoS and QoE were critical and vital. The two examples that leap to my mind are (i) Evolved Packet Core (EPC) functions such as Mobility Management Entity (MME) and BNG environments where the users need to be authorized before they can expect to receive any meaningful services.
While i understood that servers were getting powerful and Intel was doing its bit with its Data Plane Development Kit (DPDK) architecture, it didnt occur to me till recently that we would be seeing servers handling traffic at 10G+ line rate. Vyatta, a Brocade company now, uses vRouters to implement real network functions. Vyatta started with its modest 5400 vRouter that could Continue reading
How Does This Help Aruba Networks?
I was going over my YouTube subscriptions tonight, as I do at least once a week, and came across this video from Aruba Networks:
While I do love watching things go through a shredder, I fail to see the point of this video. It begs the question: Who watches this and would this video change their mind?
In my opinion, this video is aimed at a non-technical buyer. If you make a significant investment in Aruba based on this video, I have serious concerns about your ability to make sound judgements when it comes to technology. That is not to say that the AP-225 from Aruba can’t beat a Cisco 3702 AP in testing. I honestly don’t know. I have access to both AP’s, and I suppose I could run my own independent tests, but to what aim? I certainly don’t have 20 laptops laying around to run my own version of this test, and I am struggling to locate the exact testing methodology used on the Aruba website. The video mentions that Aruba publishes the exact test they performed. I assume it is available somewhere. There was nothing in the video description, so I suppose I have to do Continue reading
40th Anniversary of the TCP Protocol
40th Anniversary of the TCP Protocol
by Brian Boyko, Technology Contributor - May 20, 2014
In May of 1974, the IEEE published a paper titled “A Protocol for Packet Network Intercommunication.” The authors were Vint Cerf and Bob Kahn.
Forty years later, the protocol they developed, TCP, is still the undisputed king of “sending stuff.” It’s no longer alone in packet types, but we still use the conventions for routing and interconnecting networks that TCP established, and the basic operation hasn’t changed since 1974.
It’s a brilliant design; one that, at its most simple, comes down to a single idea: it doesn’t matter where the packets come from, how fast they get there, what order they get there, or even how many copies there are of that packet on the network - so long as they get there.
The TCP receiver can simply reassemble the sequence as it was originally transmitted, and double-check with the sending computer to ensure accuracy. The TCP slow-start means that it automatically determines the safe rate at which to send packets.
The upshot of all of this has been that TCP enabled, for the first time, the building of robust Continue reading
Show 189 – Connecting VMware to the Network
I managed to get Chris Wahl to sit down for a while and talk about where VMware ESX and networking connect. In this podcast we talk through the nature of the “VMware vSwitch” and how it’s advanced patch panel capabilities can be integrated with the physical network. Chris is well known figure in the VMware scene and recently […]
Author information
The post Show 189 – Connecting VMware to the Network appeared first on Packet Pushers Podcast and was written by Greg Ferro.
When Vision Becomes Reality
plat . form
/’patfÔrm/
noun
- an underlying computer system on which application programs can run
Working at a start-up that’s trying to create an entirely new way of doing something can take your emotions on a roller coaster ride. One minute you’re loving the fact that you’re working your tail off to create something new, innovative and different; and the next minute you’re frustrated because change takes time and you want to prove that the vision the team is chasing, but not everyone is there yet.
For the Embrane family, today is a moment when we’re reminded why we put in those hours and push through those challenges.
If you’ve followed the Embrane story, you know we’ve been touting our plans to be THE platform for delivering virtual network services to enterprises and service providers. The vision Dante and Marco had when they started Embrane was that the Embrane heleos platform not only would power our own agile network services, but we would deliver that value to third-parties. We’ve listened to our customers, identified trends and evolved our solution to prove our platform was indeed a system on which application programs can run. We spent countless hours building the premier platform Continue reading
DEMO: Using Ansible for Network Automation
There is so much discussion on if network engineers need to be programmers that I was almost getting pissed off last week. It was an odd and funny feeling. Anyway, I've written in the past here and here about the use of Ansible for networking. In this post and video, the goal is to show why network engineers don’t need to be "hardcore programmers."
Below is a short demo of using Ansible to automate basic network configuration tasks on Cisco routers. As more Ansible modules come out (or any other tool that does the job), we will quickly realize, the network engineer doesn’t need to be a “hardcore programmer,” but rather understand the tool and articulate the requirements such that new modules can easily be added by others. If the tools we’ll have in the future are “platforms” that can be customized by the consumer/customer meaning the vendor isn’t required to add more functionality, then that’ll pretty awesome for both the network engineer and the business. It’s a win win.
FYI- the modules being demo’d are leveraging Cisco’s onePK as the API to connect to and make changes to the routers.
Hope you enjoy. Continue reading
Hope you enjoy. Continue reading
Winning With Ecosystems
Back in 2010, I wrote a post entitled “Competing With Cisco”. It has been a few years, and since I have been in the VAR space for almost 3 years now, I have a slightly different perspective. One thing I didn’t really touch on too much in that article was the powerful ecosystem that surrounds Cisco. I’ve seen it win many deals over the past several years and thought it was worth writing about. Perhaps you already know the power of that ecosystem.
I feel sorry for smaller technology vendors. They face an uphill climb when going against the 800lb gorillas. Interestingly enough, I have often wondered about that phrase. Perusing the Wikipedia article on “800lb gorilla”(That site really does have everything!), it gives a riddle:
Q: Where does an 800lb gorilla sit?
A: Anywhere it wants to.
For people within the greater networking space, that 800lb gorilla is Cisco. It has been that way for a number of years, and will likely continue that trend for years to come. Although there are numerous competitors, time and time again, they fail to take substantial market share from Cisco. While Cisco does make many fantastic products, there Continue reading
The RedHat controversy
Several articles, including one in the Wall Street Journal
hit the press last week regarding RedHat policy of only supporting RedHat guests in RedHat Linux, VMWare or HyperV Hosts.
While this policy had probably been around for a while, several RedHat customers i work with have recently changed their deployment plans towards having dual hypervisor sulotions (ubuntu + RHEL) in order to be able to run RHEL hosts under support.
RedHat seems to be using this tatic to stem its market share loss in the virtualization and OpenStack hypervisor space. In a blog post, RedHat seems to imply that its competitors providing Linux hosts “cavalierly compile and ship, untested OpenStack offerings”. Ironically, several people that i spoke with last week have echoed the opinion that RHEL 6.x is rather problematic for a cloud deployment, questioning whether it can be used in production.
One cloud provider that i spoke with, immediatly replied that they had to replaced the kernel and KVM versions in their CentOS 6.x version when i questioned thier choice of OS distribution. This seems to match the general consensus of what I hear through the grapevine. I understand than an anecdote is not data but in the Continue reading
Internets of Interest for 16th May 2014
Collection of useful, relevant or just fun places on the Internets for 16th May 2014 and a bit commentary about what I’ve found interesting about them: Source Serif Pro / Wiki / Home – Adobe has open sourced a Serif Font to go with the previous Source San Pro Source Serif Pro is a […]
The post Internets of Interest for 16th May 2014 appeared first on EtherealMind.
The To DS and From DS Fields
Currently I’m studying for the Certified Wireless Analysis Professional (CWAP) exam and I’m rereading the study guide and I found the chapters that examined the different fields and elements present in the MAC header most interesting. I had a rough idea, but during my studies learned a great deal more about the unique fields and elements dedicated to wireless that keep the network functioning and help packets get delivered. Two fields of particular interest are the To Distribution System (To DS) and From Distribution System (From DS) and how these fields determine if the frame is leaving or entering the wireless environment.
Distribution System
Just a quick definition of the distribution system and basically the DS is the infrastructure that connects multiple access points together to form an Extended Service Set (ESS). The DS is typically an 802.3 Ethernet wired network, but it doesn’t have to be, and the DS can even be a wireless back haul.
MAC Header & Frame Control Field
Lets now look at the MAC header which can contain four address fields. The number of address fields is a major difference between Ethernet frames, which only use two address fields, and wireless frames that could Continue reading
Role inversion
At the OpenStack summit in Atlanta this week there was a very interesting phenomenon. Vendors that have been traditionally positioned in the I.T space seemed to be directing their energy around OpenStack on the carrier / telecom space; while vendors traditionally in this space where doing the best they could to get beyond it and into non-traditional I.T deployments.
As an example, canonical’s booth was primary advertising their “Carrier Class OpenStack” and RedHat seemed very interested in NFV; with several senior developers organizing a cross project NFV subteam to focus on how OpenStack can be a better fit for carrier data-centers.
The traditional telecom vendors on the other hand seemed to be rather less sanguine on the NFV market. At least when it comes to the timelines required to get to production deployments: 2018 seems to be a reasonable target.
I don’t currently have access to market research data; but i would be very curious to take a look at it and how it is being interpreted. Either the I.T. vendors are over-investing or the traditionally Service Provider focused vendors are under-investing in this space. Cisco, for instance, which is typically quite business savvy is nowhere to Continue reading
OpenContrail at the summit
There was a lot happening at the OpenStack summit in Atlanta this week. I got the opportunity to meet several of the most active OpenContrail developers; and envangilize the project with several people that are looking for an OpenStack networking solution that meets their needs.
The buzz on Neutron can be sumarized by: the default implementation of neutron doesn’t work. Many users find that running neutron service rack with l3-agent and dhcp agent isn’t working out for them: the neutron router is a choke point for traffic; there is no resiliency and some of the services (e.g. DHCP) are prone to melt down. This seemed to be the rought consensus of those who i spoke with (admitedly a rather un-scientific sample).
It is easy to explain the advantages of the OpenContrail implementation in this context. By implementing a fully distributed router implementation as well as distributing the DHCP, metadata proxy and floatingip functionality, OpenContrail solves most of the current pain points of Neutron.
On the other side, some of the users I spoke to where often concerned with the relativly small size of the community. Hopefully this weeks annoucement of the OpenContrail Advisory Board will help aliviate this concern. Continue reading
Cisco Live US 2014 is upon us!
Just wanted to put out a quick post and wish all the attendees, exhibitors, and staff safe travels! I know we all have a busy and exciting week ahead of us! Make sure you stop by the Social Media lounge and say hello and meet some new friends. The social media lounge is in Moscone […]My pinboard bookmarks for 17 May 2014
Things of note that were discovered on the web this week.