Comments for Network Heresy

Comment on What Should Networks Do For Applications? by manfred

manfred — Thu, 16 May 2013 03:24:44 +0000

Lennie, thanks for the pointer…but seems like you missed the point of Geoff Huston’s presentation at Ripe 65. He is arguing against QoS on the PUBLIC Internet, which for the most part I concure and doesn’t make a lot of sense.

However, here is a quote from Geoff Houston (Jun 25, 2012): “I hope I made the point that I was looking at QoS in the public provider space, not the enterprise. In the enterprise world there can be a single domain of control and a single set of policies and even a single set of client priorities that allow things that are not possible in the public space. Sometimes this distinction is just too subtle and folk can be confused by what is possible in a private or enterprise environment and what is feasible in the public space.”

QoS within the Enterprise is not about redistributing bandwidth, but rather about prioritizing real-time sensitive traffic to reduce latency and mitigate packet loss (due to micro-burst or Instantaneous buffer congestion).

There are a bunch of excuses for not doing QoS in the Enterprise and none of them are valid:
http://www.nojitter.com/post/240147232/qos-in-the-lan-youre-kidding

Worth noting is that QoS is commonly deployed in many/most Enterprise networks and works quite well. The main issue is that configuring QoS consitently is complex and difficult, which is something that we are actively working to solve using Software Defined Networking (SDN).

Here is a video of an SDN demo for Lync:

Comment on About by Victor Reijs

Victor Reijs — Wed, 08 May 2013 14:42:18 +0000

Hello Bruce,
I read about your Network Virtualisation and I was wondering if you heard about Network as a Services: NaaS (from the MANTICORE and Mantychore projects). It is an idea from the early 2000s and is a continuation of the UCLP (User Controlled Light Path) of CANARIE. But beside virtualising&abstracting the optical/ethernet layer, Mantychore project works on the IP layer and thus providing virtual networks for layer 1 to 3.
The aim is to provide operational services (in for instance HEAnet, an NREN for Ireland) where we can allow users to generate on the fly IP networks (if wanted connected to the public Internet) or to remove the Client Premises Equipment Router (by using a virtual CPE in the core). Combination with NFV (Network Function Virtualisation) concept is of course possible.

We want to see the NaaS in the same way as SaaS, IaaS, PaaS XaaS.
I also work on MaaS (Management as a Service) as part of GN3 project.

Let me know if this in some way maps your ideas of Network Virtualisation (I think it really does).

We have had several presentations from the early 2000s:
https://tnc2012.terena.org/core/event/22 (demo of IP (NaaS)and Ethernet layer (BoD) provisioning at an international scale).
https://tnc2012.terena.org/core/presentation/146 (incorporating green energy parameters into the decisions of IaaS and NaaS).
http://www.terena.org/activities/netarch/ws1/slides/reijs-NaaS-221112-NAW.pdf vCPE and MaaS)
http://www.opennaas.org/
https://www.facebook.com/OpenNaas
Planned demos are at RIPE in Dublin and TNC2013 in Maastricht.

Let me know if you are interested.

Comment on What Should Networks Do For Applications? by Lennie

Lennie — Wed, 01 May 2013 23:07:38 +0000

When I see people discus about overprovisining or QoS I always think of this talk:

https://ripe65.ripe.net/presentations/67-2012-09-25-qos.pdf
https://ripe65.ripe.net/archives/video/3/

Comment on What Should Networks Do For Applications? by Paul Gleichauf

Paul Gleichauf — Sat, 20 Apr 2013 05:29:12 +0000

Martin,
I may have been either too subtle or too abstract in making my point about constraints and that may have led you to believe that I am skeptical about application “influence” of the network.

As a side note, I also probably should also have added power as a ever more frequent and stringent constraint on data center network designs. When there are constraints that make it challenging to have a sufficiently provisioned network (to use your term), then there can be benefits to allowing applications to signal their resource needs, which may be false (related to security) or wrong, and the network may find it needs to balance. We already collectively know some of the complications of traffic engineering, but it is feasible at the cost of complexity. It appears that some significant fraction of major customers want to deliberately constrain their networks (in particular their power consumption) and still have high utilization. They also appear to require a graceful transition across hybrid networks while doing so. I am not going to argue that this is the best choice for anyone to make, but it is an interesting soluble engineering problem/requirement that I cannot reject out-of-hand.

Paul

Comment on What Should Networks Do For Applications? by manfred

manfred — Wed, 17 Apr 2013 05:15:37 +0000

Maybe you should read this NoJitter blog about an HP and Microsoft Demo how applications and network control can dynamically alter network performance and operations:

http://www.nojitter.com/post/240153039/hp-and-microsoft-demo-openflowlync-applicationsoptimized-network

Comment on What Should Networks Do For Applications? by Martin Casado

Martin Casado — Tue, 16 Apr 2013 14:11:22 +0000

OpenFlow was more about the control plane than the applications. The original work came out of an earlier project which used a single, centralized reference monitor to perform admission and access controls (per flow) of every user and device on the network. With centralization (or limited distribution) you could show strong consistency, and it wasn’t clear how a distributed approach could support end to end policies with client and server mobility and service chaining on arbitrary topologies.

I very much share your skepticism on having applications control the network, through Openflow or otherwise.

Comment on What Should Networks Do For Applications? by Martin Casado

Martin Casado — Tue, 16 Apr 2013 14:01:39 +0000

Yeah, on a reread I see why you came to that conclusion. We could have been more clear on the specific focus.

Comment on What Should Networks Do For Applications? by Paul Gleichauf

Paul Gleichauf — Tue, 16 Apr 2013 07:06:26 +0000

It is interesting that this thread has avoided mentioning Open Flow, which as I recall in its original form was about being able to craft experimental protocols that could enable applications to control a campus network. You know better than I if I have this right. Today Open Flow seems to have pivoted to be a mechanism for data center management.. Some of us resisted that notion at its inception because among other reasons less relevant to this thread there was no mechanism provided to balance competing demands from many simultaneous application demands for limited resources. If things are sufficiently over provisioned, one can demand almost anything from the network. Yet Open Flow would appear to have some challenges in responding to and monitoring a dynamically changing network, among other issues. You and your coauthors are right that the cool thing about IP over multiple paths in the data center is that it can achieve near optimal utilization (and it can do so without resorting to experimental protocols).

Comment on What Should Networks Do For Applications? by Yiannis

Yiannis — Tue, 16 Apr 2013 06:52:24 +0000

Bruce,

As a home user, I’d rather have my preferences stored on a controller’s state, instead of requiring each application and device to mark DSCP bits.. Hopefully this will be applied both at my home’s router and the ISP’s headend. This also works regardless of whether the traffic is inbound or outbound, and so I don’t have to depend on the other end (or other ISPs to the path) to set and respect the DSCP marking.

Comment on What Should Networks Do For Applications? by Paul Gleichauf

Paul Gleichauf — Tue, 16 Apr 2013 06:37:11 +0000

Martin,

I find overprovisioning and the use of multipath quite compelling and simplifying, so no argument there. When I read, and now re-read, the original article I interpreted the emphasis to be on the decoupling of applications from the physical network. That seemed a very idealistic perspective, one that even classical IP networks have trouble honoring without layer violation exceptions.