Category: Switching

My tweet about the latest proof of my layer-2 = single failure domain claim has raised numerous questions about the use of bridging (aka switching) within Internet Exchange Points (IXP). Let’s see why most IXPs use L2 switching and why L2 switching is the simplest solution to the problem they’re solving.

QFabric from Juniper is probably the best data center fabric architecture (not implementation) I’ve seen so far – single management plane, implemented in redundant controllers, and distributed control plane. The “only” problem it had was that it was way too big for data centers that most of us are building (how many times do you need 6000 10GE ports?). Juniper just solved that problem with a scaled-down version of QFabric, officially named QFX3000-M.

Stephen Hauser sent me an interesting question after the Data Center fabric webinar I did with Abner Germanow from Juniper:

A common theme in your talks is that L2 does not scale. Do you mean that Transparent (Learning) Bridging does not scale due to its flooding? Or is there something else that does not scale?

As is oft the case, I’m not precise enough in my statements, so let’s fix that first:

Just prior to Networking Field Day, the merry band of geeks sat down with Chip Copper, Brocade’s Solutioneer (a job title almost as good as Packet Herder) to discuss the intricate details of VCS Fabric. The videos are well worth watching – the technical details are interesting, but above all, Chip is a fantastic storyteller.

We’ve seen several interesting data center fabric solutions during the Networking Tech Field Day presentations, every time hearing how the new fabric technologies (actually, the shortest path bridging part of those technologies) allow us to shed the yoke of the Spanning Tree monster (see Understanding Switch Fabrics by Brandon Carroll for more details). Not surprisingly we wanted to know more and asked the obvious question: “and how would you connect the switches within the fabric?”

Last week Stephen Foskett and Greg Ferro brought back their merry crew of geeks (and a network security princess) for the third Networking Tech Field Day. We’ve met some exciting new vendors (Infineta and Spirent) and a few long-time friends (Arista, Cisco, NEC and Solarwinds).

Infineta gave us a fantastic deep-dive into deduplication math, and Spirent blew our socks off with their testing gear. As for the generic state of the networking industry, William R. Koss nicely summarized my feelings in a blog post published last Friday:

Wim (@fracske) De Smet sent me a whole set of very good VXLAN- and EVB-related questions that might be relevant to a wider audience.

If I understand you correctly, you think that VXLAN will win over EVB?

I wouldn’t say they are competing directly from the technology perspective. There are two ways you can design your virtual networks: (a) smart core with simple edge (see also: voice and Frame Relay switches) or (b) smart edge with simple core (see also: Internet). EVB makes option (a) more viable, VXLAN is an early attempt at implementing option (b).

When I was writing about the NEC+IBM OpenFlow trials, I figured out a perfect use case for OpenFlow-controlled network forwarding: SMB data centers that need less than a few hundred physical servers – be it bare-metal servers or hypervisor hosts (hat tip to Brad Hedlund for nudging me in the right direction a while ago)

I thought Edge Virtual Bridging (EVB) would be the technology transforming the kludgy vendor-specific VM-aware networking solutions into a properly designed architecture, but the launch of L2-over-IP solutions for VMware and Xen hypervisors is making EVB obsolete before it ever made it through the IEEE doors.

I didn’t expect we’d see multi-vendor OpenFlow deployment any time soon. NEC and IBM decided to change that and Tervela, a company specialized in building messaging-based data fabrics, decided to verify their interoperability claims. Janice Roberts who works with NEC Corporation of America helped me get in touch with them and I was pleasantly surprised by their optimistic view of OpenFlow deployment in typical enterprise networks.