Packets DownRange
Interconnection, peering, Data centers. How the Internet works. IXPs, transit, and other topics. Routing and Control Planes such as BGP and OSPF protocols. RPKI and IP resources are also covered.
IPv4 Subnet Mask Cheat Sheet CIDR Notation Subnet Mask Total Subnets Hosts per Subnet (usable) /8 255.0.0.0 1 16,777,214 /9 255.128.0.0 2 8,388,606 /10 255.192.0.0 4 4,194,302 /11 255.224.0.0 8 2,097,150 /12 255.240.0.0 16 1,048,574 /13 255.248.0.0 32 524,286 /14 255.252.0.0 64 262,142 /15 255.254.0.0 128 131,070 /16 255.255.0.0 256 65,534 /17 255.255.128.0 512 32,766 … Read more
A data center is the beating heart of modern businesses, housing critical IT infrastructure that powers applications, processes, and data. Behind this infrastructure lies a robust power system designed to ensure uninterrupted operation. Power systems in a data center are complex and include various types of power sources and components, each serving a unique purpose. … Read more
The Global BGP Routing Table is a comprehensive database that contains all the IP address prefixes (routes), which are advertised by ASNs, and the associated paths to reach them across the internet.
In a previous post, I asked if TCAM is still needed in modern routers. In this post, I will examine how TCAM works in routers and provide some more insight into TCAM. In a router, TCAM stores and processes rules for various functions. These rules are typically derived from: Steps for TCAM Lookup: Why Do … Read more
Physical security in a data center is critical as it serves as the first line of defense against unauthorized access, vandalism, theft, and environmental threats. Here’s a deeper dive into the various layers and strategies involved in ensuring comprehensive physical security for a data center. 1. Strategic Location Selection A. Risk Assessment for LocationChoosing the … Read more
Having done consulting for years I saw many instances where BGP, especially ibgp, was used where OSPF would have been a better fit. Sometimes, this was for a specific reason; sometimes, it was just not knowing better. I am from the school, so don’t complicate things necessarily. In this article, I will outline some of … Read more
The Internet, as we know it today, is a vast network of interconnected systems that allow seamless communication, data transfer, and access to information. But have you ever wondered how data finds its way across such a sprawling network? This is where BGP, or Border Gateway Protocol. While it operates quietly behind the scenes, BGP … Read more
Anyone who works in a data center needs the following tools. Some are essential, and some make their life easier. We all want work to be easier, right? These are just five tools I think everyone who visits a data-center or other similar place should have. These are some tools you wish you had after … Read more
In the realm of networking, BGP (Border Gateway Protocol) is a crucial component that helps determine how data is routed across the internet. One of the many attributes within BGP is MED, or Multi-Exit Discriminator. But what exactly is BGP MED, and why should you care about it? Let’s dive into the details. What Is … Read more
Originally Published in 2015So, I have a very heartwarming story today related to the WISP industry. So this started back in March. A client was having issues with a circuit. The transport provider had so many failures in troubleshooting the issue from the start. First, the tech from the transport company did not have the … Read more
As you become more familiar with Cisco Data Center terminology, you will encounter the term DCI. A DCI is a Data Center Interconnect. DCIs typically fall into three categories. Dark Fiber (CWDM/DWDM)MPLS Layer 2 VPN (VPWS/VPLS)MPLS Layer 3 VPN A DCI is basically a LAN extension over one of the above methods.
This is a great read (and well-put-together post) about undersea cables and their vital role in the Internet.https://www.theverge.com/c/24070570/internet-cables-undersea-deep-repair-ships