Five Number Summary for Network Topologies

Introduction

You may or may not have already heard about the Five Number summary for a dataset. It’s basically a set of descriptive statistics for a given dataset, which provides an idea about the dataset. Those are:

  1. Minimum
  2. First quartile
  3. Median
  4. Third quartile
  5. Maximum

Similarly, there are specific statistics about topology, which gives an idea about any network topology. The ones which I think the most essential are:

  1. Density and Sparsity
  2. Average Degree
  3. Assortativity
  4. Average Path Length
  5. Clustering Coefficient

Sample Topology

We will be using Cogent topology, which is publicly available here to follow along with our examples. The map represents the nodes in US + Mexico, and European countries.Each node color represents a specific country.

Cogent Public Topo

Graphml version Cogent Topology

You may have already noticed that in the graph, each city is represented as a Node. In reality, any city will have many routers, which will make the topology a lot bigger and more attractive. For our purposes, the current topology abstraction provides the right balance where it’s not huge to overwhelm the reader but big enough to keep things interesting.

Five Number Summary

Density and Sparsity

A Graph consists of nodes and links connecting those nodes. An obvious thing to Continue reading

AAA Deep Dive on Cisco Devices

I’ve been working on some AAA configuration lately and I went through some of my older templates and realized that I didn’t want to simply use them without verifying first if I still believed that this was the best way of configuring AAA. I started by reading some of the official docs but quickly realized they were a bit shallow and lacked any real detail of some different scenarios such as what happens when the AAA server is not available. I then realized that there also is a lack of blogs that dive into this into any detail. Being curious, I thought I would lab it out as I have recently built an ISE lab.

The goal of this post is to start with a very simple AAA configuration, expand on it, verify each step what happens when the AAA server is available and when it is not. I will give you relevant debug outputs as well as my thoughts on different parameters in the configuration. Buckle up! because this is going to be a super deep dive!

We start out by applying a simple AAA configuration, where I have specified my ISE server, which is at 192.168.128. Continue reading

Weekend Reads 011521


In response to ongoing cybersecurity events, the National Security Agency (NSA) released a Cybersecurity Advisory Thursday “Detecting Abuse of Authentication Mechanisms.” This advisory provides guidance to National Security System (NSS), Department of Defense (DoD), and Defense Industrial Base (DIB) network administrators to detect and mitigate against malicious cyber actors who are manipulating trust in federated authentication environments to access protected data in the cloud.


The current lawsuit was announced by Colorado’s Attorney General Phil Weiser but 38 states are signatories. The big issue is alleged suppression of competition.


Data analytics isn’t just for large organizations anymore. As businesses and community collectives increasingly move their operations into digital spaces, the vast amounts of data being collected pose an opportunity for them to get to know their stakeholders better.


In one of his most famous studies, 54 volunteers were served tomato soup. Half were served from normal bowls and half from “bottomless bowls” which had hidden tubes that imperceptibly refilled the bowls.


For all its breadth, depth, and skillful insertion via the supply chain, the latest hack of critical departments of the U.S. government—and of many leading corporations from around the world — should come as no surprise.


As domains Continue reading

Uganda’s January 13, 2021 Internet Shut Down

Uganda's January 13, 2021 Internet Shut Down

Two days ago, through its communications regulator, Uganda's government ordered the "Suspension Of The Operation Of Internet Gateways" the day before the country's general election. This action was confirmed by several users and journalists who got access to the letter sent to Internet providers. In other words, the government effectively cut off Internet access from the population to the rest of the world.

On Cloudflare Radar, we want to help anyone understand what happens on the Internet. We are continually monitoring our network and exposing insights, threats, and trends based on the aggregated data that we see.

Uganda's unusual traffic patterns quickly popped up in our charts. Our 7-day change in Internet Traffic chart in Uganda shows a clear drop to near zero starting around 1900 local time, when the providers received the letter.

Uganda's January 13, 2021 Internet Shut Down

This is also obvious in the Application-level Attacks chart.

Uganda's January 13, 2021 Internet Shut Down

The traffic drop was also confirmed by the Uganda Internet eXchange point, a place where many providers exchange their data traffic, on their Continue reading

The Impending AMD Milan Versus Intel Ice Lake Server Showdown

What a strange server CPU world we live in. The dozen or so biggest customers in the world command something on the order of 45 percent of the server CPU shipments, but significantly lower share of the revenue because of the volume discounts they can command, and they not only shape the product rollouts, their opinions can kill off processor SKUs long before we even know about them on announcement day. …

The Impending AMD Milan Versus Intel Ice Lake Server Showdown was written by Timothy Prickett Morgan at The Next Platform.

Technology Short Take 136

Welcome to Technology Short Take #136, the first Short Take of 2021! The content this time around seems to be a bit more security-focused, but I’ve still managed to include a few links in other areas. Here’s hoping you find something useful!

Networking

Servers/Hardware

  • Thinking of buying an M1-powered Mac? You may find this list helpful.

Security

Heavy Networking 557: User Experience Is A Full-Stack Responsibility (Sponsored)

Digital Experience Monitoring (DEM) is the topic on today's Heavy Networking. IT folks tend to view user experience from their own particular area of responsibility--networking, security, app development--but the reality is there's a common set of data that IT should consume and understand. Sponsor Catchpoint joins us to discuss its DEM platform and how it measures user experience using metrics that are relevant across the IT stack. Our guest is JP Blaho, Director, Product Marketing at Catchpoint.

Heavy Networking 557: User Experience Is A Full-Stack Responsibility (Sponsored)

Digital Experience Monitoring (DEM) is the topic on today's Heavy Networking. IT folks tend to view user experience from their own particular area of responsibility--networking, security, app development--but the reality is there's a common set of data that IT should consume and understand. Sponsor Catchpoint joins us to discuss its DEM platform and how it measures user experience using metrics that are relevant across the IT stack. Our guest is JP Blaho, Director, Product Marketing at Catchpoint.

The post Heavy Networking 557: User Experience Is A Full-Stack Responsibility (Sponsored) appeared first on Packet Pushers.

Managing Leaders, Or Why Pat Gelsinger Is Awesome

In case you missed it, Intel CEO Bob Swan is stepping down from his role effective February 15 and will be replaced by current VMware CEO Pat Gelsinger. Gelsinger was the former CTO at Intel for a number of years before leaving to run EMC and VMware. His return is a bright spot in an otherwise dismal past few months for the chip giant.

Why is Gelsinger’s return such a cause for celebration? The analysts that have been interviewed say that Intel has been in need of a technical leader for a while now. Swan came from the office of the CFO to run Intel on an interim basis after the resignation of Brian Krzanich. The past year has been a rough one for Intel, with delays in their new smaller chip manufacturing process and competition heating up from long-time rival AMD but also from new threats like ARM being potentially sold to NVIDIA. It’s a challenging course for any company captain to sail. However, I think one key thing makes is nigh impossible for Swan.

Management Mentality

Swan is a manager. That’s not meant as a slight inasmuch as an accurate label. Managers are people that have things and Continue reading

KEMTLS: Post-quantum TLS without signatures

KEMTLS: Post-quantum TLS without signatures
KEMTLS: Post-quantum TLS without signatures

The Transport Layer Security protocol (TLS), which secures most Internet connections, has mainly been a protocol consisting of a key exchange authenticated by digital signatures used to encrypt data at transport[1]. Even though it has undergone major changes since 1994, when SSL 1.0 was introduced by Netscape, its main mechanism has remained the same. The key exchange was first based on RSA, and later on traditional Diffie-Hellman (DH) and Elliptic-curve Diffie-Hellman (ECDH). The signatures used for authentication have almost always been RSA-based, though in recent years other kinds of signatures have been adopted, mainly ECDSA and Ed25519. This recent change to elliptic curve cryptography in both at the key exchange and at the signature level has resulted in considerable speed and bandwidth benefits in comparison to traditional Diffie-Hellman and RSA.

TLS is the main protocol that protects the connections we use everyday. It’s everywhere: we use it when we buy products online, when we register for a newsletter — when we access any kind of website, IoT device, API for mobile apps and more, really. But with the imminent threat of the arrival of quantum computers (a threat that seems to be getting closer and closer), we need Continue reading

Looking into Linux user logins with lslogins

One convenient way to list details about user logins on a Linux system is to use the lslogins command. You'll get a very useful and nicely formatted display that includes quite a few important details.On my system and likely most others, user accounts will start with UID 1000. To list just these accounts rather than include all of the service accounts like daemon, mail and syslog, add the -u option as shown in the example below.$ sudo lslogins -u UID USER PROC PWD-LOCK PWD-DENY LAST-LOGIN GECOS 0 root 151 0 0 root 1000 shs 68 0 0 12:35 Sandra H-S 1001 nemo 0 0 0 2021-Jan05 Nemo Demo,,, 1002 dbell 0 0 1 Dory Bell 1003 shark 2 0 0 7:15 Sharon Hark 1004 tadpole 0 0 0 2020-Dec05 Ted Pole 1005 eel 0 0 0 2021-Jan11 Ellen McDay 1006 bugfarm 0 0 0 2021-Jan01 Bug Farm 1008 dorothy 0 0 1 Dorothy Reuben 1012 jadep 0 0 1 2021-Jan04 Jade Jones 1013 myself 0 0 0 2021-Jan12 My Self 1014 marym 0 0 0 2020-Mar20 Mary McShea 1017 gijoe 0 0 0 GI Joe 65534 nobody 0 0 1 nobody What the lslogins command does is grab Continue reading

Looking into Linux user logins with lslogins

One convenient way to list details about user logins on a Linux system is to use the lslogins command. You'll get a very useful and nicely formatted display that includes quite a few important details.On my system and likely most others, user accounts will start with UID 1000. To list just these accounts rather than include all of the service accounts like daemon, mail and syslog, add the -u option as shown in the example below.$ sudo lslogins -u UID USER PROC PWD-LOCK PWD-DENY LAST-LOGIN GECOS 0 root 151 0 0 root 1000 shs 68 0 0 12:35 Sandra H-S 1001 nemo 0 0 0 2021-Jan05 Nemo Demo,,, 1002 dbell 0 0 1 Dory Bell 1003 shark 2 0 0 7:15 Sharon Hark 1004 tadpole 0 0 0 2020-Dec05 Ted Pole 1005 eel 0 0 0 2021-Jan11 Ellen McDay 1006 bugfarm 0 0 0 2021-Jan01 Bug Farm 1008 dorothy 0 0 1 Dorothy Reuben 1012 jadep 0 0 1 2021-Jan04 Jade Jones 1013 myself 0 0 0 2021-Jan12 My Self 1014 marym 0 0 0 2020-Mar20 Mary McShea 1017 gijoe 0 0 0 GI Joe 65534 nobody 0 0 1 nobody What the lslogins command does is grab Continue reading

Video: Multi-Layer Switching and Tunneling

After discussing the technology options one has when trying to get a packet across the network, we dived deep into two interesting topics:

  • How do you combine packet forwarding at multiple layers of OSI stack (multi-layer switching)?
  • What happens when you do layer-N forwarding over layer-M transport core where N <= M (example: IPv6 packets over IPv4 packets) aka tunneling?

You’ll find more details (including other hybrids like Loose Source Routing) in Multi-Layer Switching and Tunneling video.

Watch the video
The video is part of How Networks Really Work webinar and available with Free ipSpace.net Subscription.

Video: Multi-Layer Switching and Tunneling

After discussing the technology options one has when trying to get a packet across the network, we dived deep into two interesting topics:

  • How do you combine packet forwarding at multiple layers of OSI stack (multi-layer switching)?
  • What happens when you do layer-N forwarding over layer-M transport core where N <= M (example: IPv6 packets over IPv4 packets) aka tunneling?

You’ll find more details (including other hybrids like Loose Source Routing) in Multi-Layer Switching and Tunneling video.

Watch the video
The video is part of How Networks Really Work webinar and available with Free ipSpace.net Subscription.

Addressing 2020

Time for another annual roundup from the world of IP addresses. Let’s see what has changed in the past 12 months in addressing the Internet and look at how IP address allocation information can inform us of the changing nature of the network itself.

Webinar: How the Internet Really Works Part 1

On the 22nd, I’m giving a three hour course called How the Internet Really Works. I tried making this into a four hour course, but found I still have too much material, so I’ve split the webinar into two parts; the second part will be given in February. This part is about how systems work, who pays for what, and other higher level stuff. The second part will be all about navigating the DFZ. From the Safari Books site:

This training is designed for beginning engineers who do not understand the operation of the Internet, experienced engineers who want to “fill in the gaps,” project managers, coders, and anyone else who interacts with the Internet and wants to better understand the various parts of this complex, global ecosystem.

You can register here.

1 … 766 767 768 769 770 … 3,795