As Internet traffic grows and becomes more dynamic, optical transport networks for sub-sea, terrestrial long haul and metro need more capacity. The ability to deploy capacity quickly is equally important to handle the increasingly dynamic nature of the traffic. The concept of a multi-haul transport platform, as introduced by Andrew Schmitt of Cignal AI, becomes very appealing for achieving this ability to scale with speed while maintaining operational simplicity – a single platform for all requirements. A critical element of the multi-haul optical platform is the flexibility of the coherent optics to be tuned to fine granularity in order to meet the reach-capacity target of any given network.
While double checking some stats on a network I came across this in Libre. 84% is usually something that would cause me to be alarmed, as Libre is trying to tell us.
After some research, I found the following.
While it is not documented, it was noted that this was by design and that it would not affect the switch as the switchport becomes more and more loaded.
The switch allocates dedicated memory to certain processes / resources by default and then additional resources when the configuration is added. This ensures proper functionality and is again by design.
The I/O Memory pool buffers information transmitted to and from the CPU, and does not affect the actual forwarding of packets on the switch.
Translation: The switch uses up these resources by default, even if they aren’t all being used. Think of it as setting it aside for future use without dynamic allocation of them.
Outbound Route Filtering (ORF) is a Cisco proprietary feature that prevents the unnecessary exchanging of routes that are subject to inbound filtering. This, in turn, minimizes bandwidth across the links and reduces CPU cycles upon the router during the processing of the neighbor UPDATE.
ORF works by the router transmitting its inbound filters to its neighbor, which the neighboring router then applies outbound.
great article on how to do this if you are running Cisco routers and your provider is too.
At 00:00 on 1 Jan 2020 UTC, all Self-Signed Certificates (SSC) that were generated on IOS/IOS-XE systems will expire, unless the system was running a fixed version of IOS/IOS-XE when the SSC was generated. After that time, unfixed IOS systems will be unable to generate new SSCs. Any service that relies on these self-signed certificates to establish or terminate a secure connection might not work after the certificate expires.
I had a good discussion with my Buddy JJ tonight on kind of the next step of network evolution for provider networks. Many providers have evolved to MPLS networks with VPLS. There are some inherent issues with this when it comes to things like bonding, MLAG, among other issues. Nothing is perfect, right?
So as we dive into What is EVPN I want you to know I am approaching this from a service provider standpoint. I also am no EVPN expert, but I am seeing it more and more as a solution to solve specific issues. As a result, EVPN is sliding into a natural progression of the service provider network.
So what is EVPN?
There are folks much more versed on EVPN than I am. As a result, I will lean on some already written articles.
Components of EVPN
Now that you have a high-level overview of EVPN, what are some of the major components and features you should know? Let’s dive into that
Unified control plane. EVPN can be used throughout your network. You don’t have to use one stack for data center, one for metro to the data center, and yet another for connectivity between data centers. You can bring it all under one control roof so to speak.
EVPN, through BGP, marries the Layer 2 and Layer 3 layers together. With MPLS everything is controlled at the layer3 level. Now with EVPN Mac addresses become much more important. For example, Each EVPN MAC route announces the customer MAC address and the Ethernet segment associated with the port where the MAC was learned from and is associated MPLS label. This EVPN MPLS label is used later by remote PEs when sending traffic destined to the advertised MAC address. Pretty cool huh?
As networks grow network engineers learn about things such as north-south traffic and east-west traffic. Microsoft has a great article which explains this concept. https://blogs.technet.microsoft.com/tip_of_the_day/2016/06/29/tip-of-the-day-demystifying-software-defined-networking-terms-the-cloud-compass-sdn-data-flows/
East-West – East-West refers to traffic flows that occur between devices within a datacenter. During convergence for example, routers exchange table information to ensure they have the same information about the internetwork in which they operate. Another example are switches, which can exchange spanning-tree information to prevent network loops.
North | South – North- South refers to traffic flows into and out of the datacenter. Traffic entering the datacenter through perimeter network devices is said to be southbound. Traffic exiting via the perimeter network devices is said to be northbound.
So, if you are a growing Service provider look at EVPN. In some upcoming articles, I will talk more about various components of EVPN and such.
Installation of a new Cisco 100 gig switch