Ivan Pepelnjak
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Ivan Pepelnjak
Whitebox Switching: Follow the R&D Budget
A few weeks ago HP announced that they’d start selling branded whitebox (brite-box) switches, and as expected the industry press was immediately full of opinions. As always, it makes sense to follow the money (or, in this case, the R&D budget) to understand what’s going on behind the scenes.
Read more ...You must understand the fundamentals to be successful
I was speaking with a participant of the recent SDN event in Zurich after the presentations, and he made an interesting comment: whenever he experienced serious troubleshooting problems in his career, it was due to lack of understanding of networking fundamentals.
Read more ...You Must Understand the Fundamentals to Be Successful
I was speaking with a participant of an SDN event in Zurich after the presentations, and he made an interesting comment: whenever he experienced serious troubleshooting problems in his career, it was due to lack of understanding of networking fundamentals.
Let me give you a few examples: Do you know how ARP works? What is proxy ARP? How does TCP offload work and why is it useful? What is an Ethernet collision and when would you see one? Why do we need MLD in IPv6 neighbor discovery?
Networking Field Day 9 Wrap-up on Software Gone Wild
A few days after the Networking Field Day 9 event Nick Buraglio organized a virtual meetup with Brandon Carroll, Brandon Mangold, Bob McCouch and myself, and we discussed the presentations from NEC, Cumulus, Cisco and Brocade. Nick recorded the conversation and so Episode 26 of Software Gone Wild was born.
IPv6 Cheat Sheet
Just in case you're new to IPv6 and struggle with the essentials: here's an excellent cheat sheet by Jeff Carrell… and don't forget to check the amazing Cheat Sheet Library @ packetlife.net.Presentation: Automating Network Security
The fantastic Troopers 15 conference is in full swing… and I’m done with the presentations ;) The last talk I had during the conference focused on automating network security. The slides are already online; I’ll add the link to the recording when they upload the videos.
Evaluation Guide: Encryptors for Metro and Carrier Ethernet
Christoph Jaggi, the author of Metro Ethernet and Carrier Ethernet Encryption Market Overview published an awesome follow-up document: an evaluation guide that lists most of the gotchas one has to be aware of when considering encryption gear, from deployment scenarios, network overhead and key exchange details to operational considerations. If you have to deal with any aspect of network encryption, this document is a must-read.
We Have to Get Away from the Box-Focused Mentality
I had a great SDN-focused conversation with Terry Slattery during last Interop New York, ago and of course we came to the argument that the CLI is the root of all evil, which started my usual rant. Guess what: not surprisingly that wasn’t what Terry had in mind. He was using the “CLI mentality is bad” as a synonym for “we’re used to configuring our networks one box at a time” (so we should really be talking about box-focused mentality).
Read more ...TCP Optimization with Juho Snellman on Software Gone Wild
Achieving 40 Gbps of forwarding performance on an Intel server is no longer a big deal - Juniper got to 160 Gbps with finely tuned architecture - but can you do real-time optimization of a million concurrent TCP sessions on that same box at 20 Gbps?
Juho Snellman from Teclo Networks explained how they got there in Episode 25 of Software Gone Wild… and you’ll learn a ton of things about radio networks on the way.
Reducing BGP SNMP Traps in DMVPN Networks
One of my readers decided to build a large DMVPN network with BGP as the WAN routing protocol (good choice!) and configured BGP SNMP traps with snmp-server enable traps bgp command on the hub router to detect spoke router failures. Turns out that’s not exactly a good idea.
Read more ...Video: Routing over VXLAN
Even though I wrote about the challenges of routing from VXLAN VNI to VLAN segment on a certain popular chipset a while ago, many engineers obviously still find the topic highly confusing (no surprise there, it is).
Maybe a video is worth a thousand words ;) – I published the part of recent VXLAN webinar where I described the issue in as many details as I could.
Whitebox Switching and Open-Source Networking Are not SDN
One of my readers left this comment to the Four Paths to SDN blog post:
You didn't mention Cumulus. SDN protocols become much less important when you have an open Linux switch platform. You can compile and install your own management daemon and implement whatever protocol best suits the task (and blend local and remote control).
Here’s my usual response to this line of thinking:
Read more ...Estimating BGP Convergence Time
One of my readers sent me this question:
I have an Internet edge setup with two routers connected to two upstream ISPs and receiving full BGP routing table from them. I’m running iBGP between my Internet routers. Is there a formula to estimate convergence time if one of my uplinks fail? How many updates will I need to get the entire 512K routes in BGP table and also how much time it would take?
As always, the answer is it depends.
Read more ...Scalable Load Balancing with Avi Networks on Software Gone Wild
How many times have you received exact specifications of the traffic the e-commerce platform you have to deploy will generate? How do you buy a load balancer (application delivery controller in marketese) to support that (somewhat unknown) amount of traffic? In most cases, you buy a box that’s several times too big for the traffic the site is receiving most of the time, and still crashes under peak load.
Read more ...Cisco ACI – a Stretched Fabric That Actually Works
In mid-February a blog post on Cisco’s web site announced stretched ACI fabric (bonus points for not using marketing grammar but talking about a shipping product). Will it work better than other PowerPoint-based fabrics? You bet!
What’s the Big Deal?
Cisco’s ACI fabric uses distributed (per-switch) control plane with APIC controllers providing fabric configuration and management functionality. In that respect, the ACI fabric is no different from any other routed network, and we know that those work well in distributed environments.
Read more ...Free Online Introduction to SDN and Network Automation Training
Want to know more about SDN and network automation/programmability, but don’t know where to start? Why don’t you try the free Introduction to SDN and Network Automation training available on ipSpace.net – you’ll get seven hours of high-quality content that will help you understand where it might make sense to use SDN technologies in your network and what SDN, OpenFlow, NFV, NETCONF, Ansible, YAML, Jinja and a few other acronyms are all about.
Response: Why Technology Still Matters
My good friend Tom Hollingsworth wrote a great blog post about hypermyopia in the networking industry. I agree with most everything he wrote (I have to – I’m always telling people to focus on business needs and to change their mentality before relying on shiny new gizmos), but I still think it’s crucial to consider the technology used in products we’re looking at.
Read more ...Vendor-Independent European Network Conferences?
One of my readers was trying to find interesting vendor-independent network conferences in Europe. Here are a few I could recommend, please leave your feedback and additional suggestions in the comments!
Read more ...Do We Need QoS in the Data Center?
Whenever I get asked about QoS in the data center, my stock reply is “bandwidth is cheaper than QoS-induced complexity.” This is definitely true in most cases, and ideally the elephant problems should be solved higher up in the application stack, not with network-layer kludges, but are there situations where you actually need data center QoS?
Read more ...Scaling Overlay Networks: Scale-Out Control Plane
A week or so ago I described why a properly implemented hypervisor-based overlay virtual networking data plane is not a scalability challenge; even though the performance might decrease slightly as the total number of forwarding entries grow, modern implementations easily saturate 10GE server uplinks.
Scalability of the central controller or orchestration system is a totally different can of worms. As I explained in the Scaling Overlay Networks, the only approach that avoids single failure domain and guarantees scalability is scale-out control plane architecture.