Why Core or Backbone is used in Networking?
Why Core or Backbone is used in Networking?. Before we start explaining this question, let’s note that these two terms are used interchangeably. Usually, Service Providers use Backbone, and Enterprise Networks use Core terminology but they are the same thing.
Why Network Core is Necessary?
The Key Characteristics of the Core, the Backbone part of the networks are:
- High-Speed Connectivity. Today it is 100s of Gigabit networks and is usually used as a bundle to increase the capacity.
- Bringing Internet Gateway, Access, Aggregation, and Datacenter networks together. It connects many different parts of the network, and glues together.
- Redundancy and High Availability are so important. Redundant physical circuits and devices are very common.
- Failure impact is so high in this module, compared to other modules
- Full Mesh or Partial Mesh deployment is seen mostly as these type of topologies provides the most amount of redundancy and the direct path between the different locations.
- Commonly known in the Operator community as Backbone or ‘P Layer
Redundancy in this module is very important.
Most of the Core Network deployments in ISP networks are based on Full Mesh or Partial Mesh.
The reason for having full mesh physical connectivity in the Core network Continue reading
Multicast BIER – Bit Indexed Explicit Replication
Multicast BIER – RFC8279
Bit Index Explicit Replication – BIER is an architecture that provides optimal multicast forwarding through a “BIER domain” without requiring intermediate routers to maintain any multicast-related per-flow state. BIER also does not require any explicit tree-building protocol for its operation.
So, it removes the need for PIM, MLDP, P2MP LSPs RSVP, etc.
A multicast data packet enters a BIER domain at a “Bit-Forwarding Ingress Router” (BFIR), and leaves the BIER domain at one or more “Bit-Forwarding Egress Routers” (BFERs).
The BFIR router adds a BIER header to the packet.
The BIER header contains a bit-string in which each bit represents exactly one BFER to forward the packet to.
The set of BFERs to which the multicast packet needs to be forwarded is expressed by setting the bits that correspond to those routers in the BIER header.
Multicast BIER Advantages
The obvious advantage of BIER is that there is no per-flow multicast state in the core of the network and there is no tree building protocol that sets up trees on-demand based on users joining a multicast flow.
In that sense, BIER is potentially applicable to many services where Multicast is used.
Many Service Providers currently investigating Continue reading
Navigating NSX Module in PowerCLI 12.6
With the release of PowerCLI 12.6, a new module VMware.Sdk.Nsx.Policy was added to provide PowerShell binding for NSX Policy Manager APIs. This new module is auto generated from the NSX Policy API spec exposing all the features related to policy objects in NSX. The module also exposes cmdlets to Create/Edit/Delete NSX objects. This blog explains the use of PowerCLI NSX module, goes through all the different ways new cmdlets can be found and shows how to view documentation on the cmdlets with examples.
Navigating the new cmdlets
Along with the cmdlets to connect, disconnect and modify the NSX objects, there are a few helper cmdlets that make looking up new relevant cmdlets very easy.
The first one is Get-NsxOperation. This is a new feature in VMware.Sdk.Nsx.Policy and is ideal with you need to find the PowerCLI command that corresponds to an API operation and vice versa. You can also narrow down the search result using Where-Object and Select-Object filters.
Example:
Get-NsxOperation -Method GET -Path '/infra/segments'
Since the cmdlets by default returns all paths that start with /infra/segments you can also limit the search to exact match with client-side filter:
Get-NsxOperation -Method get Continue reading
The Secure Service Edge (SSE) is Broken: Here’s the Fix
The main problem with SSE, which separates the network component from secure access service edge (SASE), is that it defeats the core premise of the integrated application-centric approach to serve applications anywhere for users anywhere.Tech Bytes: HashiCorp’s Consul Tackles Network Infrastructure Automation (Sponsored)
Welcome to this sponsored Tech Bytes episode with HashiCorp, where we focus on how HashiCorp's Consul product helps automate network infrastructure. We also dig into what’s included in the Enterprise version of Consul. Joining us today is Hari Sankaran from the Consul product team.
The post Tech Bytes: HashiCorp’s Consul Tackles Network Infrastructure Automation (Sponsored) appeared first on Packet Pushers.
Tech Bytes: HashiCorp’s Consul Tackles Network Infrastructure Automation (Sponsored)
Welcome to this sponsored Tech Bytes episode with HashiCorp, where we focus on how HashiCorp's Consul product helps automate network infrastructure. We also dig into what’s included in the Enterprise version of Consul. Joining us today is Hari Sankaran from the Consul product team.Hedge 131: Easier for the Computer or the Person?
One of the mainstays of scripting—and now network management—are increasingly focused on making things “easier” for the human operator. Does this focus on making things “easier” for the operator produce a better experience, though? Or does it create frustration as humans try to “outguess” the computer’s programming and process? Join Tom Ammon and Russ White as they discuss the problems with scripting, automation, and ease-of-use.
Dig through SERVFAILs with EDE
It can be frustrating to get errors (SERVFAIL response codes) returned from your DNS queries. It can be even more frustrating if you don’t get enough information to understand why the error is occurring or what to do next. That’s why back in 2020, we launched support for Extended DNS Error (EDE) Codes to 1.1.1.1.
As a quick refresher, EDE codes are a proposed IETF standard enabled by the Extension Mechanisms for DNS (EDNS) spec. The codes return extra information about DNS or DNSSEC issues without touching the RCODE so that debugging is easier.
Now we’re happy to announce we will return more error code types and include additional helpful information to further improve your debugging experience. Let’s run through some examples of how these error codes can help you better understand the issues you may face.
To try for yourself, you’ll need to run the dig or kdig command in the terminal. For dig, please ensure you have v9.11.20 or above. If you are on macOS 12.1, by default you only have dig 9.10.6. Install an updated version of BIND to fix that.
Let’s start with the output of an example Continue reading
How we improved DNS record build speed by more than 4,000x
This post is also available in 简体中文, 日本語, Español.
Since my previous blog about Secondary DNS, Cloudflare's DNS traffic has more than doubled from 15.8 trillion DNS queries per month to 38.7 trillion. Our network now spans over 270 cities in over 100 countries, interconnecting with more than 10,000 networks globally. According to w3 stats, “Cloudflare is used as a DNS server provider by 15.3% of all the websites.” This means we have an enormous responsibility to serve DNS in the fastest and most reliable way possible.
Although the response time we have on DNS queries is the most important performance metric, there is another metric that sometimes goes unnoticed. DNS Record Propagation time is how long it takes changes submitted to our API to be reflected in our DNS query responses. Every millisecond counts here as it allows customers to quickly change configuration, making their systems much more agile. Although our DNS propagation pipeline was already known to be very fast, we had identified several improvements that, if implemented, would massively improve performance. In this blog post I’ll explain how we managed to drastically improve our DNS record propagation speed, and the Continue reading
ipSpace.net Blog Is in a Public GitHub Repository
I migrated my blog to Hugo two years ago, and never regretted the decision. At the same time I implemented version control with Git, and started using GitHub (and GitLab for a convoluted set of reasons) to host the blog repository.
After hesitating for way too long, I decided to go one step further and made the blog repository public. The next time a blatant error of mine annoys you fork it, fix my blunder(s), and submit a pull request (or write a comment and I’ll fix stuff like I did in the past).
Another way MPLS breaks traceroute
I recently got fiber to my house. Yay! So after getting hooked up I started measuring that everything looked sane and performant.
I encountered two issues. Normal people would not notice or be bothered by either of them. But I’m not normal people.
I’m still working on one of the issues (and may not be able to disclose the details anyway, as the root cause may be confidential), so today’s issue is traceroute.
In summary: A bad MPLS config can break traceroute outside of the MPLS network.
What’s wrong with this picture?
$ traceroute -q 1 seattle.gov
traceroute to seattle.gov (156.74.251.21), 30 hops max, 60 byte packets
1 192.168.x.x (192.168.x.x) 0.302 ms <-- my router
2 194.6.x.x.g.network (194.6.x.x) 3.347 ms
3 10.102.3.45 (10.102.3.45) 3.391 ms
4 10.102.2.29 (10.102.2.29) 2.841 ms
5 10.102.2.25 (10.102.2.25) 2.321 ms
6 10.102.1.0 (10.102.1.0) 3.454 ms
7 10.200.200.4 (10.200.200.4) 2. Continue readingIntroducing our brand new (and free!) Calico Azure Course
Calico Open Source is an industry standard for container security and networking that offers high-performance cloud-native scalability and supports Kubernetes workloads, non-Kubernetes workloads, and legacy workloads. Created and maintained by Tigera, Calico Open Source offers a wide range of support for your choice of data plane whether it’s Windows, eBPF, Linux, or VPP.
We’re excited to announce our new certification course for Azure, Certified Calico Operator: Azure Expert! This free, self-paced course is the latest in our series of four courses. If you haven’t had a chance to complete our previous courses, I highly recommend enrolling in them in the following order (or as you prefer).
- Certified Calico Operator: Level 1
- Certified Calico Operator: AWS Expert
- Certified Calico Operator: eBPF
What will you gain from this course?
Whether you have little to no experience with cloud concepts, have entry-level DevOps and engineering experience, are keen to learn more about Azure or are already an Azure expert looking for a cloud networking and security solution, you will benefit from this course.
The course provides an introduction to Azure cloud, learnings about managed, self-managed and hybrid cluster deployment using Calico in Azure, and offers hands-on labs to help you explore most of Continue reading