The Autumn Cloud/SDN Roadtrip

One of my kids recently asked me whether I plan to travel somewhere during the autumn. The answer was “a bit” surprising: Boston (just got back), Zurich, Bern, Stockholm, Ljubljana, Heidelberg, Nuremberg, Rome, Miami, Ljubljana, Helsinki, and maybe Munich and/or another trip to Zurich… so I might not be able to blog as frequently as usual.

Most of those trips are public events (hyperlinked). If you’re anywhere close one of those cities, check them out and drop by.

Business Critical Apps & the DMVPN Underlay of IWAN’s Intelligent Path Control

Let’s assume we have a Branch with 1 Router and 2 WAN connections.  We decide to use Intelligent Path Control with PfRv3 and design our policy such that the business critical traffic goes over one of the WAN clouds (MPLS, for example) and will use the other WAN cloud (Internet, for example) should a certain level of impairment (delay, loss, jitter) occur on the primary path.

But that business critical traffic is well….. critical to your business.  So that probably isn’t really good enough. Let’s take this a couple steps further to make sure your business critical traffic is treated as such.

With Intelligent Path Control with PfRv3 what will actually happen is that while the business critical traffic is going over the primary channel, a backup channel will be created over the other WAN cloud. On top of that, PfRv3 will be checking the health of the path the backup channel is taking.  Actually… let me be even more specific.  PfRv3 will be checking the health of the exact path that business critical traffic would take if it were to be sent over the fallback WAN cloud.

“How is this accomplished?

Regardless of hashing algorithms Continue reading

The Changing Mobile World

Today’s Internet is undoubtedly the mobile Internet. Sales of all other forms of personal computers are in decline and the market focus is now squarely on tablets, “smart” phones and wearable peripherals. You might think that such significant volumes and major revenue streams would underpin a highly competitive and diverse industry base, but you’d be wrong. In 2014 84% of all of the new mobile smart devices were using Google’s Android platform, and a further 12% were using Apple’s iOS system. This consolidation of the platform supply into just two channels is a major change. Further changes are happening. In a world as seemlingly prodigious as the mobile Internet it’s scarcity that is driving much of these changes, but in this particular case it’s not the scarcity of IPv4 addresses. It’s access to useable radio spectrum.

Arista joins Cisco, Dell at 25G

Arista Networks this week became the latest major vendor to roll data center switches that support 25G, 50G and 100Gbps Ethernet.Arista also upgraded its operating system software to support the new switches and give them a number of new features to enhance uptime, and avoid resets and reloads.The new Arista 7060X, 7260X and 7320X fixed-leaf and modular spineswitches are based on Broadcom’s Tomahawk chipset. Tomahawk silicon delivers 3.2Tbps switching capacity – 32 100G ports -- and SDN-optimized engines in a single chip, and features all-25G per-lane interconnect, enabling transformation to 25G and 50G Ethernet networks and eventually up to 100G.To read this article in full or to leave a comment, please click here

Mainstream Cloud Networking with Flexible Ethernet

Networking vendors have long touted distinct routers and switches with different LAN and WAN interfaces. Remember IBM Token Ring versus Ethernet? Or ATM or Sonet versus Ethernet or more recently Fibre Channel SANs versus Ethernet? Ethernet truly addresses the present state and next generation of networking, usually obsoleting the alternatives. Ethernet has proven its evolution...
Continue reading »

Networking Heresy?

Software Defined Networking, and it’s latest incarnation SD-WAN seem to be all the rage at the moment.  Having seen presentations from vendors large and small on the subject recently at Networking Field Day 10 I am still given to thinking there are a few things that get glossed-over by the vendors quite often.  Foremost in my mind, is this (potentially heretical thought):

It is all very well creating virtual or ‘overlay’ networks which run over other networks to suit your purposes, but as someone famous once said, you can’t change the laws of physics.   Packets must ultimately flow across a medium – wires, fibres or waves.  The media doesn’t give a flying fart whether the packet is naked, or clothed in layers of MPLS or GRE headers – if that medium is congested and doesn’t support any form of packet prioritisation, your data is down the dunny.

There’s a trade-off here that perhaps not many people understand when they are shown smooth presentations by manufacturers.  It seems to me that:

  1. Efficient use of network connectivity requires deep understanding from end to end. That’s why you employ network engineers.
  2. Efficient deployment of network connectivity requires abstraction and overlays to increase ease of deployment (which equals loss of understanding of lower layer protocols).
  3. Continue reading

Networking Heresy?

Software Defined Networking, and it’s latest incarnation SD-WAN seem to be all the rage at the moment.  Having seen presentations from vendors large and small on the subject recently at Networking Field Day 10 I am still given to thinking there are a few things that get glossed-over by the vendors quite often.  Foremost in my mind, is this (potentially heretical thought):

It is all very well creating virtual or ‘overlay’ networks which run over other networks to suit your purposes, but as someone famous once said, you can’t change the laws of physics.   Packets must ultimately flow across a medium – wires, fibres or waves.  The media doesn’t give a flying fart whether the packet is naked, or clothed in layers MPLS or GRE headers – if that medium is congested and doesn’t support any form of packet prioritisation, your data is down the dunny.

There’s a trade-off here that perhaps not many people understand when they are shown smooth presentations by manufacturers.  It seems to me that:

  1. Efficient use of network connectivity requires deep understanding from end to end.
  2. Efficient deployment of network connectivity requires abstraction and overlays (which equals loss of understanding of lower layer protocols).
  3. Efficient operation of network connectivity…  well… let’s hope it’ll be fine so long Continue reading

White House won’t say if it’s hoping for a cybersecurity deal with China

With the visit of Chinese premier Xi Jinping just a week away, the White House won't say whether one of its goals is to reach an agreement with China over cybersecurity.Hacking has been one of the issues at the forefront of U.S.-China relations over the last couple of years, particularly after the U.S. accused China of hacking into sensitive federal government systems, something that China denies."We've been pretty blunt in describing the concerns that we have with China's behavior in cyberspace," White House press secretary Josh Earnest told reporters on board Air Force One on Monday, according to a pool report.But Earnest wouldn't comment on any measures that might be taken ahead of the visit.To read this article in full or to leave a comment, please click here

Just some quick points about DHCP

Okay, so everybody knows DHCP pretty well.

I just want to point out a few little details as background for a future post:

DHCP Relays Can Change Things
The first point is about those times when the DHCP client and server aren't on the same segment.

In these cases, a DHCP relay (usually running on a router) scoops up the helpless client's broadcast packets and fires them at the far away DHCP server. The server's replies are sent back to the relay, and the relay transmits them onto the client subnet.

The DHCP relay can change several things when relaying these packets:
  • It increments the bootp hop counter.
  • It populates the relay agent field in the bootp header (The DHCP server uses this to identify the subnet where the client is looking for a lease).
  • It can introduce additional DHCP options to the request.
The last one is particularly interesting. When a DHCP relay adds information to a client message, it can be used by the DHCP server for decision-making or logging purposes. Alternatively, the added information can be used by the DHCP relay itself: Because the relay's addition will be echoed back by the server, the relay can parse Continue reading

Study names the five most hackable vehicles

A study released by a forensic consultancy has singled out the top five vehicles most susceptible to hacking.The results of the study, by PT&C|LWG Forensic Consulting Services, were based on published research by hackers, vehicle recall information and media reports.The most hackable list includes the 2014 Jeep Cherokee, the 2014 Infiniti Q50, the 2015 Cadillac Escalade, the 2010 and 2014 Toyota Prius and the 2014 Ford Fusion.To read this article in full or to leave a comment, please click here

How Uber Scales Their Real-time Market Platform

Reportedly Uber has grown an astonishing 38 times bigger in just four years. Now, for what I think is the first time, Matt Ranney, Chief Systems Architect at Uber, in a very interesting and detailed talk--Scaling Uber's Real-time Market Platform---tells us a lot about how Uber’s software works.

If you are interested in Surge pricing, that’s not covered in the talk. We do learn about Uber’s dispatch system, how they implement geospatial indexing, how they scale their system, how they implement high availability, and how they handle failure, including the surprising way they handle datacenter failures using driver phones as an external distributed storage system for recovery.

The overall impression of the talk is one of very rapid growth. Many of the architectural choices they’ve made are a consequence of growing so fast and trying to empower recently assembled teams to move as quickly as possible. A lot of technology has been used on the backend because their major goal has been for teams to get the engineering velocity as high as possible.

After a understandably chaotic (and very successful) start it seems Uber has learned a lot about their business and what they really need to Continue reading

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