Juniper EX Virtual-Chassis notes
I’ve been deploying some EX VCs recently so this post will go over some configuration and verification commands. To start with I have two EX4200s in my lab connected via the built-in VC ports. I’m running code version 12.3R6.6 VC Ports When booting this type of configuration, the switches will automatically attempt to create a […]802.11ac Adjacent Channel Interference (ACI)
I was reading this article on development of 5G cellular technologies when this bit on OFDM deficiencies and the need for new waveforms to support higher capacities and user densities caught my attention (emphasis added by me):4G and 4G+ networks employ a type of waveform called orthogonal frequency division multiplexing (OFDM) as the fundamental element in the physical layer (PHY). In fact, almost all modern communication networks are built on OFDM because OFDM improved data rates and network reliability significantly by taking advantage of multi-path a common artifact of wireless transmissions. However as time and demands progress, OFDM technology suffers from out-of-band spectrum regrowth resulting in high side lobes that limit spectral efficiency. In other words, network operators cannot efficiently use their available spectrum because two users on adjacent channels would interfere with one another. OFDM also suffers from high peak-to-average ratio of the power amplifier, resulting in lower battery life of the mobile device. To address OFDM deficiencies, researchers are investigating alternative methods including generalized frequency division multiplexing, filter bank multi-carrier, and universal filter multi-carrier. Researchers speculate that using one of these approaches over OFDM may improve network capacity by 30 percent Continue reading
Dealing with Schema Changes
It’s not often I get to write about concepts rooted in database technology, but I’d like to illuminate a situation that software developers deal with quite often, and one that those entering this space from the network infrastructure side may want to consider.
Software will often communicate with other software using APIs – an interface built so that otherwise independent software processes can send and receive data between each other, or with other systems. We’re finding that this is a pretty hyped-up buzzword in the networking industry right now, since network infrastructure historically has had only one effective method of access, and that is the CLI; not exactly ideal for anything but human beings.
These APIs will typically use some kind of transport protocol like TCP (many also ride on top of HTTP), in order to get from point A to point B. The data contained within will likely be some kind of JSON or XML structure. As an example, here’s the output from a Nexus 9000 routing table:
<?xml version="1.0"?>
<ins_api>
<type>cli_show</type>
<version>0.1</version>
<sid>eoc</sid>
<outputs>
<output>
<body>
<TABLE_vrf>
<ROW_vrf>
<vrf-name-out>default</vrf-name-out>
<TABLE_addrf>
<ROW_addrf>
<addrf>ipv4</addrf>
<TABLE_prefix>
<ROW_prefix>
<ipprefix>172.16.41.1/32</ipprefix>
<ucast-nhops>1</ucast-nhops>
<mcast-nhops>0</mcast-nhops>
<attached>FALSE</attached>
<TABLE_path>
<ROW_path>
<ipnexthop>172. Continue reading
Run desktop environment on guest VM in cloonix network simulator
The Cloonix open-source network simulator uses the Spice remote desktop system to provide a virtual desktop connection to quest virtual machines that run a graphical user interface, such as Microsoft Windows or a Linux desktop environment.
To use a graphical desktop user interface on a guest VM, we access the VM using the Spice desktop console.
Guest VM requirements
We must be running a guest VM that has a desktop environment installed and the Spice server installed.
We already upgraded a root filesystem with the XFCE desktop in a previous post. So, in this example, we will use that filesystem, which is named jessie-networking-xfce.qcow2 and is saved in the cloonix bulk directory.
Start the guest VM
Start the cloonix graph interface (see instructions for starting cloonix). Configure the VM object to load the jessie-networking-xfce.qcow2 filesystem.
Configure VM to use filesystem with desktop already installed
Then drag the VM object onto the graph interface so it starts up.
A Cloonix guest VM is now running
Use Spice to connect to the guest VM
Right-click on the VM and select the Open Spice desktop menu command.
Open the Spice desktop console on the guest VM
The Spice console will Continue reading
Server Bootstrap & Prep with Ansible
Over the past few months, I’ve been posting on using Ansible for network automation. Changing things up a bit, this post will cover using Ansible for server automation and I’ll share a few Ansible playbooks that I’ve built and have been using to bootstrap servers and prep them for various applications such as OpenStack and NSX deployments.
Step 1 - Playbook 1
Creating password-less root account
Since Ansible uses SSH by default for connecting to the servers, you will realize the first thing that needs to be done is to copy the public key of where you will execute playbooks from onto the “new” server. To do this, I use a playbook that is called server_one_time_run.yml. You will notice that in this playbook, and only in this playbook, I have remote_user set to jedelman and sudo set to yes.
I’ve been testing against bare-metal and virtual machine installs using an Ubuntu ISO image. During the OS install process, “jedelman” is the account that was created on all hosts and virtual machines.
This playbook runs and copies over the public key in the root directory. We are essentially creating a password-less login for Continue reading
Creating password-less root account
Since Ansible uses SSH by default for connecting to the servers, you will realize the first thing that needs to be done is to copy the public key of where you will execute playbooks from onto the “new” server. To do this, I use a playbook that is called server_one_time_run.yml. You will notice that in this playbook, and only in this playbook, I have remote_user set to jedelman and sudo set to yes.
I’ve been testing against bare-metal and virtual machine installs using an Ubuntu ISO image. During the OS install process, “jedelman” is the account that was created on all hosts and virtual machines.
This playbook runs and copies over the public key in the root directory. We are essentially creating a password-less login for Continue reading
Dealing with Schema Changes
It’s not often I get to write about concepts rooted in database technology, but I’d like to illuminate a situation that software developers deal with quite often, and one that those entering this space from the network infrastructure side may want to consider. Software will often communicate with other software using APIs - an interface built so that otherwise independent software processes can send and receive data between each other, or with other systems.Dealing with Schema Changes
It’s not often I get to write about concepts rooted in database technology, but I’d like to illuminate a situation that software developers deal with quite often, and one that those entering this space from the network infrastructure side may want to consider. Software will often communicate with other software using APIs - an interface built so that otherwise independent software processes can send and receive data between each other, or with other systems.Secret Sunday #2 – Schprokits
This weekend’s interesting link is to a post by Jeremy Schulman, formerly Director of Network Automation with Juniper Networks, but now the founder of Schprokits, a startup which aims to generate automation framework tools for network professionals that are of … Continue reading
If you liked this post, please do click through to the source at Secret Sunday #2 – Schprokits and give me a share/like. Thank you!
War Stories: Gratuitous ARP and VRRP
Continuing our theme of ARP-related war stories, here’s another ARP/switching behaviour I’ve come across. This particular problem didn’t result in any outages, but the network wasn’t working as well as it should have, and started flooding frames unexpectedly. Here’s what was going on:
The Network
Breaking the network down to its simplest level, it looked like this:
The two routers were a VRRP pair. Router-A was 100.100.100 .11, Router-B was 100.100.100.12, and the virtual IP was 100.100.100.1. These acted as a default gateway for the client LAN. PCs connected to the client LAN got their network configuration from DHCP, and set their default gateway to 100.100.100.1. Using this, they were able to get access to resources behind the routers, such as Server-1 at 200.200.200.200. All worked well.
Obviously there was a lot more to the network than what I’ve shown here, but it’s not important.
The Issue
I said it was working well – so what was wrong? One day I was using Wireshark to diagnose a network issue between PC-A and Server-1. I ran Wireshark on PC-A, with a capture filter of “host 200.200.200.200″. The packet flow Continue reading
Taking the Bull by the Horns
Over the past few years, I’ve had the opportunity to work with best and the brightest in the industry. The reach started with my co-workers, partners, and vendors, but gradually expanded due to the likes of maintaining a blog and occasionally being on Twitter. In a recent exchange with someone who gave me a massive pivot and jump start in my career almost 10 years ago, it reminded me of a presentation this same person gave back then.
One of the key themes of this presentation was “Intrinsic Motivation.” This was the first time I had ever heard the phrase – the speaker talked about one’s inner desire and self-motivation as the reason for wanting, learning, and doing. It’s a feeling that is hard to describe, but I remember thinking during the presentation, “Hmm, I think I may have that.” It’s not something many of us talk about, but those that have it can often see it or sense it in others. On the surface, it could be called a passion. It could be a hobby you love or when work starts to overlap as your hobby. Maybe it’s just OCD coupled Continue reading
Podcast Spotlight — Software Gone Wild
Today’s podcast spotlight goes to Software Gone Wild. This is a newer podcast hosted by our friend Ivan Pepelnjak. The topics are focused on the growing pains the networking industry is experiencing and various forms of automation that are attempting to solve them. This includes various aspects of SDN, NFV and how others are using technology to deliver bigger/better/faster solutions.
Recent episodes include Network Automation @ Spotify and The F-Script with my good friend John Herbert.
Links
- Software Gone Wild
- Follow Ivan Pepelnjak (@ioshints) on twitter
Disclaimer: I have no affiliation with the Software Gone Wild podcast or any organization linked to, represented in or derived from content found in this article. This article represents my own opinions and may not be that of my employer.
The post Podcast Spotlight — Software Gone Wild appeared first on PacketU.
Refactoring Code: Fun With REST and JSON
Recently I’ve been writing some automation code for Atlassian’s JIRA project management / bug tracking product. Think of JIRA as a generic AGILE-aware tool that can provide everything from project tracking all the way down to task tracking, trouble ticketing … Continue reading
If you liked this post, please do click through to the source at Refactoring Code: Fun With REST and JSON and give me a share/like. Thank you!
What Happens When 20 Programs Poll The Network?
Packetpushers show 198 was a great episode about Network Automation. At one point, Greg asks:
“What happens when you’ve got 20 apps polling one device?”
Well, you might hit the same problem I did:
SECURITY-SSHD-6-INFO_GENERAL : Incoming SSH session rate limit exceeded
I have some Python scripts that poll performance and configuration data from a couple of ASR9Ks, and I was getting some gaps in my data. The scripts run on different polling cycles (some hourly, some every 15 minutes, etc). It wasn’t consistent, but now and then my script would fail to collect any data.
I dug into it, and found that I was hitting the default SSH rate limit of 60 per minute, calculated as 1 per second. Because I couldn’t control the exact scheduling of when my polls ran, I inserted a short random wait timer into some of them. That helped, and I had fewer failures, but it still wasn’t quite right.
So I used the command “ssh server rate-limit 120″ to allow 2 SSH connections per second. That has helped, and now I’m not getting any failures.
But it won’t be pretty if I do have 20 different apps all trying to poll at once.
(Yes, I know, I should Continue reading
Network Break 13
We have renamed the show to "The Network Break"Network Break 13
We have renamed the show to "The Network Break"
Author information
The post Network Break 13 appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Network Break 13
We have renamed the show to "The Network Break"
The post Network Break 13 appeared first on Packet Pushers.
HP VSR1001 Virtual Services Router on GNS3
HP VSR is a Comware 7 router software application for a server which provides the same functionality as a physical router. Installed on either VMware or KVM virtual machine it offers routing, Firewall, IPSec, and MPLS VPN security services.
The tutorial gives you some ideas how to install HP VSR1000 (Virtual Service Router) running Comware 7 OS on Qemu disk and connects Qemu appliance to GNS3.
They are HP VSR1001, VSR1004 and VSR1008 models available for download. Differences between models are explained here. As the VSR1001 model has the lowest RAM requirements comparing to other models and we do not have to concern the forwarding performance, VSR 1001 demo ISO image is our choice. The demo is full featured, performance limited and requiring no license and with no expiration date.
HP VSR1001 Minimum Hardware Requirements
- CPU: 2.0 GHz
- Memory: 1 GB
- Disk space: 8 GB
- Network interfaces: 2 virtual NICs, E1000 and VirtIO virtual NICs are recommended, maximum 16 NICs supported
1. Download HP VSR1001 Virtual Services Router
Navigate to the Download page here
Picture 1 - HP VSR1001 Virtual Services Router Download Page
Click on the button >> on he right, beside the padlock icon. Either sign in with your HP Passport account or Continue reading
CCIE Collaboration Update – Racks and Videos
Update 1: CCIE Collaboration Racks are now available for rent. Sign in to your members account and click on Rack Rentals in the left navigation. Please note that these racks are currently in general beta release, meaning they are available to everyone, but if you happen to find a bug or an issue with the scheduler, rack control page, or rack equipment, please start a support case and kindly let us know about it so that we may remediate it quickly. We’ve had a number of closed beta testers and their tests have all gone very well. We should be out of general beta release within a few weeks. Full instructions on how to use our racks can be found in our new Collaboration Rack Rental Guide, and I will be releasing a few follow-up videos later today with links inside the guide, to further demo things and walk you through how to use these racks, including the use our new rack control panel.
Please note that while we do certainly still support L2VPN for connecting your phones directly, as well as SSL VPN for server access, we also provide support now for 100% VPN-less connectivity with only Continue reading
No turning back: Russia activates Crimean cable
| The Crimean peninsula depends critically on the Ukrainian mainland for infrastructure services: power, water, and Internet. That has begun to change in the last few days, as Crimean ISPs began receiving their first Internet services over the newly constructed Kerch Strait Cable, linking Crimea with the Russian mainland. The message: there is no turning back now in the process of infrastructure consolidation. |
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| It’s a symbolic step that’s been months in the making. Following Russia’s annexation of Crimea from Ukraine in March, Prime Minister Dmitry Medvedev ordered the immediate construction of a new submarine cable across the Kerch Strait, one that would connect mainland Russia to the peninsula. |
At Medvedev’s direction, Russian state-owned telecommunications company Rostelecom quickly constructed a submarine cable across the Kerch Strait at a cost of 400-900 million rubles (11-25 million US dollars). On April 25th, Rostelecom announced that the cable was completed.
But laying a short cable through shallow littoral waters is simple work, compared to the process of convincing Crimea’s ISPs to accept Internet service — any Internet service — from a Russian carrier. April passed, and then May, and June. We knew that when the Continue reading
SolarWinds NPM 11 – Now Application Aware
I had a chance last week to speak with a couple of folks at Solarwinds about the release of their Network Performance Monitor (NPM) 11 product, which is being announced today. I don’t cover network management products too often, but Solarwinds … Continue reading
If you liked this post, please do click through to the source at SolarWinds NPM 11 – Now Application Aware and give me a share/like. Thank you!