Building network automation solutions

9 module online course

Start now!

EVPN/VXLAN or Bridged Data Center Fabric?

An attendee in the Building Next-Generation Data Center online course sent me an interesting dilemma:

Some customers don’t like EVPN because of complexity (it is required knowledge BGP, symmetric/asymmetric IRB, ARP suppression, VRF, RT/RD, etc). They agree, that EVPN gives more stability and broadcast traffic optimization, but still, it will not save DC from broadcast storms, because protections methods are the same for both solutions (minimize L2 segments, storm-control).

We’ll deal with the unnecessary EVPN-induced complexity some other time, today let’s start with a few intro-level details.

read more see 3 comments

netlab Release 1.3.1: BGP local-as, FRR and Cumulus Data Plane Enhancements

netlab release 1.3.1 contains major additions to FRR and Cumulus Linux, and new BGP features:

Here are some of the other goodies included in this release:

read more see 2 comments

The Basics of Network Address Translation (NAT)

The last video in the 2-hour-long Network Addressing part of How Networks Really Work discusses Network Address Translation.

After watching it, you might want to spend some extra quality time (with a bit of soap opera vibe) enjoying the recent Dual ISP deployment operational issues and uncertainties thread on the v6ops mailing list with a “surprising” result: NPTv6 or NAT66 is the least horrible way to do it.

You need Free ipSpace.net Subscription to watch the video, and the Standard ipSpace.net Subscription to register for upcoming live sessions.
add comment

Multi-Cloud: Myths and Reality

I keep hearing numerous variations of the following argument from people believing in the unlimited powers of multi-cloud1 (deploying your workloads in multiple public cloud providers):

We don’t install all our servers in the same DC. But would you trust one Cloud Server Provider with all your applications? That’s why you should use multi-cloud.

I’ve been hearing similar arguments for at least 30 years, including:

read more see 2 comments

VLAN Interfaces and Subinterfaces

Early bridges implemented a single bridging domain across all ports. Within a few years, we got multiple bridging domains within a single device (including bridging implementation in Cisco IOS). The capability to have multiple bridging domains stretched across several devices was still missing… until the modern-day Pandora opened the VLAN box and forever swamped us in the complexities of large-scale bridging.

read more add comment

Infrastructure-as-Code Sounds Scary

One of my readers preparing for public cloud deployment sent me an interesting observation:

I pushed to use infrastructure-as-code as we move to Azure, but I’m receiving a lot of pushback due to most of the involved parties not having any experience with code. Management is scared to use any kind of “homegrown” tools that only a few would understand. I feel like I’m stuck deploying and managing the environment manually.

It looks like a bad case of suboptimal terminology for this particular audience. For whatever reason, some infrastructure engineers prefer to stay as far away from programming as possible1, and infrastructure-as-code sounds like programming to them.

read more see 1 comments

Fun Times: Is Cisco ACI Dead?

A recent blog post by Andrew Lerner asks whether Cisco ACI is dead. According to Betteridge’s law of headlines, the answer is NO (which is also Andrew’s conclusion), but I liked this gem:

However, Gartner assesses that Nexus Dashboard Fabric Controller is the optimal fabric management software for most Cisco data center environments.

An automation intent-based system provisioning a traditional routed network is considered a better solution than a black-box proprietary software-defined blob of complexity? Who would have thought…

see 2 comments

From Bits to Application Data

Long long time ago, Daniel Dib started an interesting Twitter discussion with this seemingly simple question:

How does a switch/router know from the bits it has received which layer each bit belongs to? Assume a switch received 01010101, how would it know which bits belong to the data link layer, which to the network layer and so on.

As is often the case, Peter Paluch provided an excellent answer in a Twitter thread, and allowed me to save it for posterity.

read more see 1 comments

How Routers Became Bridges

Network terminology was easy in the 1980s: bridges forwarded frames between Ethernet segments based on MAC addresses, and routers forwarded network layer packets between network segments. That nirvana couldn’t last long; eventually, a big-enough customer told Cisco: “I don’t want to buy another box if I already have your too-expensive router. I want your router to be a bridge.

Turning a router into a bridge is easier than going the other way round1: add MAC table and dynamic MAC learning, and spend an evening implementing STP.

read more see 1 comments

netlab Release 1.3: VXLAN and EVPN

netlab release 1.3 contains two major additions:

  • VXLAN transport using static ingress replication or EVPN control plane – implemented on Arista EOS, Cisco Nexus OS, Dell OS10, Nokia SR Linux and VyOS.
  • EVPN control plane supporting VXLAN transport, VLAN bridging, VLAN-aware bundles, and symmetric IRB – implemented on Arista EOS, Dell OS10, Nokia SR Linux, Nokia SR OS (control plane), VyOS, and FRR (control plane).

Here are some of the other goodies included in this release:

read more add comment
Sidebar