Overlay networking has been around for a year or so now and the ideas behind it are well established. It was about 3/4 weeks ago while researching VTEP functionality in Dell and Arista switches that I realised I could build manually configured tunnels with VXLAN and get the same results as an EoMPLS x-connect with almost zero effort. More importantly, I don’t have to pay for expensive hardware that has MPLS functions or pay again for software licenses to upgrade with MPLS features.
Stumbled over “AgilePorts” feature in Arista products this week: Arista’s AgilePorts technology enables the combination of four 10GbE SFP+ interfaces into a single 40GbE interface leveraging the parallel lane technology present in the 40GBASE-CR4 and 40GBASE-SR4standards. With AgilePorts, each 10GbE interface emulates one of the four parallel lanes, which are then driven by a 40GbE […]
I’ve been working on a lot of diagrams lately and pondering how to represent network architectures. I’ve been reading The Visual Display of Quantitative Information to get some inspiration on different approaches. I continue to be fascinated by the power of a network diagram that is well thought out and visually pleasing. And this fascination has led to my own focus on different network diagrams. In this post I’m thinking out loud one the different ways to represent information.
I was commissioned by GigaOmPro to write a report on “SDN Challenges in Large Scale Deployments”. I spoke with a number of network and virtualization engineers about their perspectives on SDN, the challenges they faced and how they would use Software Defined Networking in their data centres. It was evident during the research phase is that many people are not clear on what Overlay Networking is and just how deeply Overlay Networking will change Data Centre architecture and especially the nature of the networking and security domains.
I was going to call this article “Ethernet Switches for Virtualisation Engineers” but, really, everyone should have some understanding of the internals of an Ethernet switch. But particularly I want to focus on how multicast and broadcasts are handled in a high speed, low latency environment like a Data Centre Network.
It’s vital to understand that latency is critical to your application performance. It is common for a single transaction to take hundreds of round trips so a small increase in latency on each round trip has a large impact on the perceived performance. The client will send a chunk of data and wait for acknowledgement. Even setting up the TCP connection takes a few round trip – remember that TCP sessions are setup, and each data transfer is confirmed.
A modern network switch will have latency around 10 microseconds. The Cisco Nexus 7000 is about 8 microseconds & Brocade VDX 8770 claims less than 4 microseconds. There are many reasons why a switch can be faster or slower but I’ll look at a specific example
Remember, the latency interval is the time taken to receive a packet, decode the address, lookup the forwarding table, switch the packet (and copy it if needed) and transmit out of an Ethernet interface. That’s really fast processing. How does an Ethernet switch do this ?
Network Engineers have to manage a lot of information. Products, technologies, textbooks, study notes and research material as well as new protocols and features. Just simple tasks like keeping product manuals handy for 40 or 50 products is a real problem. How do you keep the information organised, referenced, accessible and useful ?
This three part screencast is about how I manage all the “inputs” so I don’t feel lost in information after many, many people asked.
Lots in insight for Enterprise people to consider when defending your network against DDoS attacks. At CloudFlare, an attack needs to get over about 5Gbps to set off alarms with our ops team. Even then, our automated network defenses usually stop attacks without the need of any manual intervention. When an attack gets up in […]