One of the comments I received after publishing the Use VRFs for VXLAN-Enabled VLANs claimed that:
I’m firmly of the belief that VXLAN should be solely an access layer/edge technology and if you are running your routing protocols within the tunnel, you’ve already lost the plot.
That’s a pretty good guideline for typical data center fabric deployments, but VXLAN is just a tool that allows you to build multi-access Ethernet networks on top of IP infrastructure. You can use it to emulate E-LAN service or to build networks similar to what you can get with DMVPN (without any built-in security). Today we’ll use it to build a VRF Lite topology with two tenants (red and blue).
One of the comments I received after publishing the Use VRFs for VXLAN-Enabled VLANs claimed that:
I’m firmly of the belief that VXLAN should be solely an access layer/edge technology and if you are running your routing protocols within the tunnel, you’ve already lost the plot.
That’s a pretty good guideline for typical data center fabric deployments, but VXLAN is just a tool that allows you to build multi-access Ethernet networks on top of IP infrastructure. You can use it to emulate E-LAN service or to build networks similar to what you can get with DMVPN (without any built-in security). Today we’ll use it to build a VRF Lite topology with two tenants (red and blue).
The post Decoding TCP flags in NetFlow and IPFIX. appeared first on Noction.
Dear friend,
Today we’ll look into a question, which is raising quite often on various meetups related to network automation or various threads that is the addition of any automation components (say, NetBox) to the existing networking managing suit, where you already have some inventory (say, LibreNMS). We’ll take a look into multiple approaches and, as usual, will share some code snippets how you can do that.
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5 No part of this blogpost could be reproduced, stored in a
retrieval system, or transmitted in any form or by any
means, electronic, mechanical or photocopying, recording,
or otherwise, for commercial purposes without the
prior permission of the author.
Integrating different automation tools is typically the most labor-intensive work, as it requires understanding of the tools you are integrating, their internal hierarchy and APIs capabilities. That is not even saying that you shall be proficient with a variety of technologies, such as REST API or GRPC API, JSON/Protobuf/XML, Postman and many other tools. That’s a lot, and may be not easy to start with.
The good news is that all these things you can learn at out Network Automation Training programs:
A Markov chain or Markov process is a stochastic model describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event. It is named after the Russian mathematician Andrey Markov.
Markov chains help model many real-word processes, such as queues of customers arriving at the airport, queues of packets arriving at a Router, population dynamics. Please refer to this link for a quick intro to Markov chains.
Let’s use a simple example to illustrate the use of Markov Chains. Assume that you own a barber shop, and You notice that Customers don’t wait if there is no room in the waiting room and will take their business elsewhere. You want to invest to avoid this, and you have the following info in hand:
You have finite space in the shop, so add two more chairs in the waiting room or add another barber. Now Continue reading
TL;DR
Never trust show commit changes diff
on Cisco IOS XR.
Cisco IOS XR is the operating system running for the Cisco ASR, NCS, and
8000 routers. Compared to Cisco IOS, it features a candidate
configuration and a running configuration. In configuration mode, you can
modify the first one and issue the commit
command to apply it to the running
configuration.1 This is a common concept for many NOS.
Before committing the candidate configuration to the running configuration, you
may want to check the changes that have accumulated until now. That’s where the
show commit changes diff
command2 comes up. Its goal is to show the
difference between the running configuration (show running-configuration
) and
the candidate configuration (show configuration merge
). How hard can it be?
Let’s put an interface down on IOS XR 7.6.2 (released in August 2022):
RP/0/RP0/CPU0:router(config)#int Hu0/1/0/1 shut RP/0/RP0/CPU0:router(config)#show commit changes diff Wed Nov 23 11:08:30.275 CET Building configuration... !! IOS XR Configuration 7.6.2 + interface HundredGigE0/1/0/1 + shutdown ! end
The +
sign before interface HundredGigE0/1/0/1
makes it look like you did
create a new interface. Maybe there was a typo? No, the diff is just broken. If
you Continue reading
Cloudflare has been using ingress anycast (advertising the same set of prefixes from all data centers) for ages. Now they did a giant leap forward and implemented another “this thing can never work” technology: egress anycast. Servers from multiple data centers use source addresses from the prefix that’s advertised by all data centers.
Not only that, in the long-established tradition they described their implementation in enough details that someone determined enough could go and implement it (as opposed to the typical look how awesome our secret sauce is approach from Google).
Cloudflare has been using ingress anycast (advertising the same set of prefixes from all data centers) for ages. Now they did a giant leap forward and implemented another “this thing can never work” technology: egress anycast. Servers from multiple data centers use source addresses from the prefix that’s advertised by all data centers.
Not only that, in the long-established tradition they described their implementation in enough details that someone determined enough could go and implement it (as opposed to the typical look how awesome our secret sauce is approach from Google).
Today on Heavy Networking, modeling your network with Batfish. Batfish is an open-source project that builds a model of your production network based on a snapshot of your network and device configurations. Engineers can then test and validate changes against this model before making those changes to the production network. Guest Rick Donato walks us through how Batfish works, use cases, and more.
The post Heavy Networking 658: Using Batfish To Model And Test Your Network appeared first on Packet Pushers.
Time for another netlab video: after explaining how netlab fits into the virtual lab orchestration picture, let’s answer the next question: what exactly can netlab do?
Time for another netlab video: after explaining how netlab fits into the virtual lab orchestration picture, let’s answer the following question: what exactly can netlab do?
The post IPv6 Link-Local Next Hop Capability for BGP appeared first on Noction.
The post IPv6 Link-Local Next Hop Capability for BGP appeared first on Noction.
In a previous post, we have discussed how to decrypt TLS traffic using a transparent […]
The post Capturing Decrypted TLS Traffic with Arkime first appeared on Brezular's Blog.