Flowcontrol, port buffers and dropped packets
A few days ago a customer called worried by the flowcontrol counters increasing on his Cisco 4510 switch, he just sent me this asking for an explanation: CORE_4510#show interfaces flowcontrol Port Send FlowControl Receive FlowControl RxPause TxPause admin oper admin …Vocus Acquisition of FX: Good for Customers?
Consolidation is happening in the New Zealand wholesale ISP market, with Vocus acquiring FX. Consolidation can lead to less competition, or it can strengthen it, by making players stronger and more viable. This acquisition should strengthen the market, and hopefully open up new service offerings.
In July Vocus Communications announced its intention to acquire FX Networks. From the press release:
FX owns a unique and high quality fibre optic network consisting of 4,132 kms of modern ducted fibre cable covering both the North and South Islands of New Zealand. The company has 365 customers including 43 of the Top 100 companies in New Zealand.
Vocus will acquire FX for an enterprise value of NZ$115.8m (~A$107.7m). The FX business is expected to deliver NZ$13.5-$14.5m of EBITDA in the first 12 months post acquisition (excluding transaction and integration expenses).
The combination of Vocus and FX strengthens both businesses. Vocus will emerge as the third largest network operator in NZ and the clear leader in trans-Tasman telecommunications and data centres.
Vocus has their own fibre network around Australia, and has a significant international network, with high-level peering. In 2012 they purchased Maxnet, a New Zealand ISP and Data Center Continue reading
ipSpace.net Is on CloudFlare (and IPv6)
After a week of testing, I decided to move the main ipSpace.net web site (www.ipspace.net) as well as some of the resource servicing hostnames to CloudFlare CDN. Everything should work fine, but if you experience any problems with my web site, please let me know ASAP.
2014-08-27: Had to turn off CloudFlare (and thus IPv6). They don't seem to support HTTP range requests, which makes video startup time unacceptable. Will have to move all video URLs (where the HTTP range requests are expected coming from streaming clients) to a different host name, which will take time.
Collateral benefit: ipSpace.net is now fully accessible over IPv6 – register for the Enterprise IPv6 101 webinar if you think that doesn’t matter ;)
Useful Links — Cisco Quicklinks
I just wanted to take a quick moment to share a site Dan DeBusschere has created. This site is a list of very useful config snippets, information and links. Most of the content is focused on Datacenter and UCS. If you support this type of environment, check it out.
Disclaimer: This article includes the independent thoughts, opinions, commentary or technical detail of Paul Stewart. This may or may not reflect the position of past, present or future employers.
The post Useful Links — Cisco Quicklinks appeared first on PacketU.
Your Docker agenda for VMworld 2014
Next week starts the gigantic VMworld conference at the Moscone Center in San Francisco, California. If you are attending the conference, come visit us at the Docker booth #230 and make sure to attend the following Docker-related talks, demos, discussions and meetups where you can meet and chat with fellow Dockerites:
Monday, August 25th:
3:30 PM – 4:30 PM, Moscone West, Room 2014
VMware NSX for Docker, Containers & Mesos by Aaron Rosen (Staff Engineer, VMware) and Somik Behera (NSX Product Manager, VMware)
This session will provide a recipe for architecting massively elastic applications, be it big data applications or developer environments such as Jenkins on top of VMware SDDC Infrastructure. We will describe the use of app isolation technologies such as LxC & Docker together with Resource Managers such as Apache Mesos & Yarn to deliver an Open Elastic Applications & PaaS for mainstream apps such as Jenkins as well as specialized big data applications. We will cover a customer case study that leverages VMware SDDC to create an Open Elastic PaaS leveraging VMware NSX for Data communication fabric.
5:30 PM – 6:30 PM, Moscone West, Room 2006
VMware and Docker – Better Together by Ben Golub (CEO, Continue reading
Orchestrating Docker containers in production using Fig
In the last blog post about Fig we showed how you could define and run a multi-container app locally.
We’re now going to show you how you can deploy this app to production. Here’s a screencast of the whole process:
Let’s continue from where we left off in the last blog post. First, we want to put the code we wrote up onto GitHub. You’ll need to initialize and commit your code into a new Git repository.
$ git init $ git add . $ git commit -m "Initial commit"
Then create a new repository on GitHub and follow the instructions for how to set up a remote on your local GitHub repository. For example, if your repository were called bfirsh/figdemo, you’d run these commands:
$ git remote add origin [email protected]:bfirsh/figdemo.git $ git push -u origin master
Next, you’ll need to get yourself a server to host your app. Any cloud provider will work, so long as it is running Ubuntu and available on a public IP address.
Log on to your server using SSH and follow the instructions for installing Docker and Fig on Ubuntu.
$ ssh root@[your server’s IP address] # curl -sSL https://get.docker.io/ubuntu/ | Continue reading
What is an Automatic Transfer Switch (Power)?
In response to the power redundancy article I wrote yesterday, a few comments came in. One of them (thanks, Mike!) mentioned an automatic transfer switch (ATS), a useful tool in a redundant power strategy. What is an ATS? There are many types of electrical transfer switches whose primary purpose is to divert the […]Announcing Docker 1.2.0
The hardworking folk at Docker, Inc. are proud to announce the release of version 1.2.0 of Docker. We’ve made improvements throughout the Docker platform, including updates to Docker Engine, Docker Hub, and our documentation.
Highlights include these new features:
restart policies
We added a --restart flag to docker run to specify a restart policy for your container. Currently, there are three policies available:
- no – Do not restart the container if it dies. (default)
- on-failure – Restart the container if it exits with a non-zero exit code.
- Can also accept an optional maximum restart count (e.g. on-failure:5).
- always – Always restart the container no matter what exit code is returned.
This deprecates the --restart flag on the Docker daemon.
A few examples:
- Redis will endlessly try to restart if the container exits
docker run --restart=always redis
- If redis exits with a non-zero exit code, it will try to restart 5 times before giving up:
docker run --restart=on-failure:5 redis
–cap-add –cap-drop
Currently, Docker containers can either be given complete capabilities or they can all follow a whitelist of allowed capabilities while dropping all others. Further, previously, using --privileged would grant all capabilities inside a container, rather than applying a whitelist. This was not Continue reading
Missing Synergies & HP’s SDN
As someone who’s been monitoring HP’s SDN strategy for years now, news that Bethany Mayer is headed to Ixia is rather interesting. Despite HP’s networking division having had some successes and gaining small bits of market share here and there, the fact they they are leaders in the SDN space seems to go unnoticed by the […]Cloud Orchestration System Is an Ideal Controller Use Case
A while ago I explained why OpenFlow might be a wrong tool for some jobs, and why centralized control plane might not make sense, and quickly got misquoted as saying “controllers don’t scale”. Nothing could be further from the truth, properly architected controller-based architectures can reach enormous scale – Amazon VPC is the best possible example.
Read more ...Leveraging Cisco NX-API with Ansible to Make Your Life Easier
I had a conversation recently with someone who has more of a sysadmin background. We started talking about the intersection of DevOps and networking and while his environment wasn’t large, there was one pain point he talked about – he doesn't have access to the network switches to ensure they are configured properly for “his” servers and to ensure packets aren't being dropped, etc. when there are issues with the application, server, or network. And by the way, he really doesn't want access to the data center switches, because after all, many fear logging into network devices that are in production.
Could DevOps and network automation help here?
Could DevOps and network automation help here?
In fact, the answer is yes. The goal is to get the right data into the right hands as quick as possible. An automation platform can be used to query the switch to get the exact data the admin needs. For those that have help desks supporting large campus networks, the same philosophy can be used there as well. Help desk, junior admins, and cross-functional team members can now get what they need in just a few seconds.
In order to test this out, I’ve Continue reading
In order to test this out, I’ve Continue reading
FabricPath Multidestination Trees
FabricPath has many advantages over the classical Spanning Tree Protocol. Mainly because it can use ECMP (Equal Cost Multi Paths) Routing. For unicast frames it uses the well known Switch-ID that is inserted in a FabricPath header. This will be explained in a future post for sure. I have been intrigued regarding how multicast […]Street Power vs. UPS Power In Redundant Power Supply Devices
A question came into the Packet Pushers mailbox along these lines. If a unit has two power inputs, should one go to UPS and one to street power, or is it better to have both power supplies fed by the same UPS? The issue with raw street power is that it isn’t conditioned. […]Load Balancing Lab setup
Virtual Loadblanacers
Nowadays, you don't need a physical load balancer to setup a lab. Almost each and every vendor offers a "virtual appliance", which is just their appliance repacked as a virtual machine:Here is a list of few such virtual loadbalancers:
There are even opensource alternatives such as:
- OpenBSD's relayd - in OpenBSD very few tutorials are needed as the man pages are complete, but here are some few links: tutorial1 tutorial2. It has full support for many advance loadbalncer's features.
I plan to try it out. - nginx
- Linux LVS
So building a virtual lab on a laptop is just one download away, isn't it?
No, there are to missing pieces: Network topology with a router and web servers with content which is suitable for such labs.
Luckily for you, I have just setup such a lab, and I welcome you to use it as well.
Network topology
Basic topology
The usual loadbalancer lab looks like this:
But this is not how loadbalncers are usually deployed. And its also not the best way to deploy them, as not all traffic needs to go through the loadbalancer.
Realistic topology
.png) |
| Topology Continue reading |
Quick Take: Wider Channel Widths Are Flashy but Not Efficient
I've been thinking of writing a well-articulated blog post on why the preference for high-density Wi-Fi networks is smaller channel width over larger channel width. This post is NOT that.Instead, I was on Twitter articulating some of the logical points why smaller channel widths provide better aggregate capacity than larger channel widths (assuming you deploy enough radios and take advantage of all the spectrum at your disposal). Here is a quick recap of those points.
You might want to reference my SNR to MCS Index Mapping Table, which shows why larger channels result in a reduction in modulation rate that can often offset the gain from using the wider bandwidth in the first place. And my 802.11ac Receiver Sensitivity charts show that you have to have a really great signal strength for wider channels to even be considered, but watch out in your design because overcompensating to achieve higher signal strength will increase co-channel interference (CCI) which travels a LONG ways! Finally, my post on 802.11ac Adjacent Channel Interference (ACI) shows that wider channels create more ACI than smaller channels, and ACI is even more detrimental and unfriendly than CCI. Therefore, radio receivers require greater adjacent channel Continue reading
Democratizing the Networking Industry beyond the Two Party System
When it comes to the networking industry and purchasing a network device, a user typically has two choices: Party D and Party R.
Sure, there are other parties out there, but they usually don’t make the ballot for one reason or another. Even when you are not a “hardcore” supporter of either party, you feel stuck in one of those camps since you cannot partially “vote,” much less mix-and-match, as both parties are incompatible with each other.
What if this doesn’t have to be the case?
In this new world democracy, what if you could apportion your vote in a piecemeal fashion? In essence, taking the bits from one party combined with those of another party to create a new candidate tailored for your needs.
For the last 18 months or so, the Open Compute Project (OCP) Networking Group has been further validating and accelerating the adoption of this new reality of a disaggregated network design where the network device is separated from the network operating system (NOS) that powers the device. At the heart of this is a little piece of OCP software called ONIE (Open Network Install Environment), a key innovation by Cumulus Networks and released Continue reading
Network Break 15
The Network Break returns with Show 15.
Author information
The post Network Break 15 appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Windows ISATAP Client, Part 2
In Part 1 we discussed how to turn off ISATAP on Windows host—which is a great idea. Turning off unnecessary components of your network simplifies everything. But ISATAP can be useful in certain scenarios. For instance, if you want to test an application on IPv6 you clearly don’t want to turn on IPv6 everywhere and […]
Author information
The post Windows ISATAP Client, Part 2 appeared first on Packet Pushers Podcast and was written by Dan Massameno.
Musing: First thoughts on how Cisco ACI Works
I've been reading the Cisco Application Centric Infrastructure Design Guide. Sometimes I see a product of genius and wondrous use of technology, other times I'm like 'did they do it the hard way or what' ?
The post Musing: First thoughts on how Cisco ACI Works appeared first on EtherealMind.