CCIE vs CCDE
Probably one of the mostly asked questions by the networking experts. CCIE vs CCDE. How many times you asked yourself or discussed with someone else about this ? I think many times. right ? I have CCIE Routing Switching and/or Service Provider, should I continue to Design certificates such as CCDE or should I study… Read More »
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HTIRW: Reality at the Mic (1)
We’ve talked a little about the structure of the IETF, and the process a draft follows when moving from submission to draft to RFC… The perennial question is, though — why does it take so long? Or, perhaps — why is the IETF so broken? Let me begin here: the IETF is a human organization. […]
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The post HTIRW: Reality at the Mic (1) appeared first on Packet Pushers Podcast and was written by Russ White.
Estimating BGP Convergence Time
One of my readers sent me this question:
I have an Internet edge setup with two routers connected to two upstream ISPs and receiving full BGP routing table from them. I’m running iBGP between my Internet routers. Is there a formula to estimate convergence time if one of my uplinks fail? How many updates will I need to get the entire 512K routes in BGP table and also how much time it would take?
As always, the answer is it depends.
Read more ...Install Mininet on an Amazon EC2 server
To install the Mininet SDN network simulator on a remote server running on Amazon’s EC2 cloud1, follow the procedure shown below. After installing it, I did some basic tests and it seems that Mininet works well on the Amazon EC2 server.
From my laptop PC, I connect to the Amazon EC2 instance via SSH. In the example below, the server’s private key file AWS-PrivateKey.pem is stored in the folder ~/AWS and the server’s public IP address is 55.155.1.55. I had previously created a new user brian on the server.
brian@Laptop:~$ ssh -X -i ~/AWS/AWS-PrivateKey.pem [email protected]
To install the latest stable version of Mininet, plus all supporting software, execute the following commands on the Amazon EC2 server running Ubuntu Server 14.04.
brian@AWS:~$ sudo apt-get install git
brian@AWS:~$ git clone git://github.com/mininet/mininet
brian@AWS:~$ mininet/util/install.sh -a
To test the installation, run the following command:
brian@AWS:~$ sudo mn --test pingall
The benefit of installing Mininet on a remote server such as an Amazon EC2 instance is that I can now experiment with Mininet from any computer, including a tablet or smartphone, at any time as long as I have a connection Continue reading
CCIE R&S — By the Numbers
When I started studying in earnest for my CCIE, I started a log of how I was spending my time studying, which books and papers I'd read, videos I'd watched, and so on. I thought it would be a neat exercise to look back afterwards at what it took to achieve this goal. I'm also somewhat self-deprecating and tend to minimize my accomplishments, so having this data is a way for me to remember that this wasn't a small accomplishment at all.
Choosing CoreOS over Project Atomic
Upon hearing the news that Red Hat had released the Atomic Host variant of Red Hat Enterprise Linux, I decided that it would be a good idea for me to take a look at the CentOS flavor of the Atomic Host variant. In case you’re unfamiliar, the Atomic Host variant is the result of Project Atomic, which aimed to provide a container-optimized flavor of RHEL/CentOS/Fedora. This container-optimized flavor would leverage rpm-ostree for atomic system updates (hence the name) and come with Docker preinstalled. What I found, frankly, disappointed me.
Before I continue, I will make two very important disclaimers:
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Note that there has been no official announcement of the release of final builds of an Atomic Host variant for CentOS 7. So, it’s entirely possible that all the issues I mention here are known issues that will be addressed. That being said, I did find CentOS 7 Atomic Host builds dated March 5, 2015; this is the same date as the Red Hat announcement. It’s reasonable, therefore, to believe that these builds are very close to final builds.
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It’s entirely possible these issues are the result of errors on my part. I’ve spent most of my time with Continue reading
(Semi-)Automated ~/.ssh/config management
Shorten your ssh commands, but in a kludgy way.March Meetup Challenge
Firstly wanted to thank everyone who participated in the February Network Topology Photo Challenge! There were some amazing topologiesThe Year of IPv6?
IPv6 adoption has been slow. But I think it’s reaching a tipping point. I’m very close to calling 2015 “The year of IPv6.” There’s plenty of people who won’t believe me, but the statistics are very interesting. You need to keep a close on eye on what the data is saying.
Recently I asked the question “What percentage of Internet traffic needs to be IPv6 for you to consider IPv6 to be mainstream/arrived/the year of IPv6?”
@bobbobob had the best answer for when IPv6 can be considered ‘mainstream’:
@northlandboy When I see criminal minds, or law and order using a poorly faked IPV6 address when they're 'hacking', I'll say it's arrived.
— Rabbit Sultan (@bobbobob) February 21, 2015
But @icemarkom was probably technically correct with this answer:
@northlandboy More than 50%.
— Marko Milivojevic (@icemarkom) February 20, 2015
So how far away is that? It’s tough trying to measure IPv6 adoption. Traffic patterns are region- & user-specific. The services that Chinese users access are different to those that a New Zealand business users. Traffic is often concentrated with a few ISPs and/or a few big services (Google, Facebook, Twitter, etc).
I like to use the Google IPv6 statistics Continue reading
What is the difference between throughput & goodput?
Throughput Throughput is the rate at which data is traversing a link. For example, take a look at the virtual router output below. The throughput rate is 643Kbps in each direction. [crayon-54facc3328376599378258/] Goodput Goodput is the rate at which useful data traverses a link. Assuming an uncongested path between endpoints, goodput and throughput will […]OSPF Design Considerations
Introduction
Open Shortest Path First (OSPF) is a link state protocol that has been around for a long time. It is geneally well understood, but design considerations often focus on the maximum number of routers in an area. What other design considerations are important for OSPF? What can we do to build a scalable network with OSPF as the Interior Gateway Protocol (IGP)?
Prefix Suppression
The main goal of any IGP is to be stable, converge quickly and to provide loop free connectivity. OSPF is a link state protocol and all routers within an area maintain an identical Link State Data Base (LSDB). How the LSDB is built it out of scope for this post but one relevant factor is that OSPF by default advertises stub links for all the OSPF enabled interfaces. This means that every router running OSPF installs these transit links into the routing table. In most networks these routes are not needed, only connectivity between loopbacks is needed because peering is setup between the loopbacks. What is the drawback of this default behavior?
- Larger LSDB
- SPF run time increased
- Growth of the routing table
To change this behavior, there is a feature called prefix suppression. When Continue reading