My friend Jeremy Stretch wrote an IPAM+DCIM tool for Digital Ocean and open-sourced it. As the tool was designed by networking engineers to manage data center networks (more in Jeremy’s blog post), it might be a better fit than other tools out there. In any case, check it out and let me know how it works.
In older IOS Code, there was a specific requirement for redistributing OSPF Subnets. In almost every case, the keyword “subnets” had to be added to the redistribute command.
//notice the warning when 'subnets' is omitted R1(config)#router ospf 1 R1(config-router)#redistribute eigrp 1 % Only classful networks will be redistributed //and the configuration is stored exactly as it was typed R1(config-router)#do show run | sec router router ospf 1 log-adjacency-changes redistribute eigrp 1 //we can change the behavior by adding 'subnets' R1(config-router)#redistribute eigrp 1 subnets //after adding, it is stored as one would expect R1(config-router)#do show run | sec router router ospf 1 log-adjacency-changes redistribute eigrp 1 subnets
When I tested this in VIRL running 15.6(1S) running inside of IOS XE 3.17, the warning goes away. The question I had is whether it is still relevant or not.
//without the 'subnets' keyword csr1000v-2(config)#router ospf 1 csr1000v-2(config-router)#redistribute eigrp 1 csr1000v-2(config-router)#do show run | sec router router ospf 1 redistribute eigrp 1 //with the 'subnets' keyword csr1000v-2(config-router)#redistribute eigrp 1 subnets csr1000v-2(config-router)#do show run | sec router router ospf 1 redistribute eigrp 1 subnets
I initially spent some time experimenting with this and thought that ‘subnets‘ had Continue reading
A recent blog post posed the question Why do we use the Linux kernel's TCP stack?. It triggered a very interesting discussion on Hacker News.
I've also thought about this question while working at CloudFlare. My experience mostly comes from working with thousands of production machines here and I can try to answer the question from that perspective.
CC BY 2.0 image by John Vetterli
Let's start with a broader question - what is the point of running an operating system at all? If you planned on running a single application, having to use a kernel consisting of multiple million lines of code may sound like a burden.
But in fact most of us decide to run some kind of OS and we do that for two reasons. Firstly, the OS layer adds hardware independence and easy to use APIs. With these we can focus on writing the code for any machine - not only the specialized hardware we have at the moment. Secondly, the OS adds a time sharing layer. This allows us to run more than one application at a time. Whether it's a second HTTP server or just a bash session, this ability to share resources Continue reading
Despite the hype, the WiFi technology has a number of practical limitations.
Having a circle of reliable industry peers and colleagues can play a major role in advancing your IT career.
Building overlay networks using tunnels was always done to achieve connectivity between isolated networks that needed to share the same policies, VLANs or security domains. In particular, they represent a strong use-case in the data center, where tunnels are created between the hypervisors in different locations allowing virtual machines to be provisioned independently from the physical network.
The open source project also reaches out to rkt.
Aligned Data Centers is using all of Plexxi's main products.
He used to work in Microsoft's Bing Search group.