SDN Archives – Page 2 of 2 – The Broadcast Knowledge

Video: Red and Blue, or Purple; Your IP Media Network, Your Way

Posted on 4th September 2019 by Adam K

Leaf & spine networks have started taking over data centres in the last few years. It’s no secret that people prefer scale-out over scale-up solutions and you can see a similar approach in ST 2110 networks, when large monolithic video switches are replaced with smaller leaf and spine switches.

Leaf and spine refers to networks where a number of main, high throughput switches link to a number of smaller switches. These smaller switches tend to be aggregators and offer the promise of cheaper ports delivered closer to your equipment. The alternative to leaf & spine is monolithic switches which do have their merits, but are certainly not always the right choice.

To provide non-blocking switching in leaf & spine networks you need an SDN controller that orchestrates media flows. Advances in SDN capabilities have led to the emergence of “Purple” network architectures. In this video Gerard Phillips from Arista shows how it differs from a “Red/Blue” architecture, how path diversity is maintained and how ST 2110 IP live production or playout applications could benefit from it.

It’s important to be aware of the different uses of Layer 2 vs Layer 3:

• Layer 3 have distributed IGMP management since PIM is used on each router to route multicast traffic, so there is no more flooding network with unnecessary traffic. This type of network works well with high bit rate video multicasts, but as IGMP is not bandwidth aware, it’s best to use an SDN system for flow orchestration.

Gerard then looks at resilience:

Using 2022-7 seamless switching (plus a robust monitoring system that can provide quick, accurate information to resolve the issue)
Choosing quality components (switches, NOS, fibres etc.)
Providing redundancy (redundant PSU, fans, fabric modules etc., redundant links between switches, ensuring that routing protocol or SDN can use these “spares”)
Dividing up failure domains
Using leaf and spine architecture (routing around failed components with SDN)
Using resilient IP protocols (BGP, ECMP)

The talk finishes up discussing the pros and cons of the different architectures available:

Monolithic systems which are non-blocking, but have a wide failure domain
Monolithic – expansion toward spine and leaf with SDN for non-blocking switching
Leaf & spine with air-gapped Red and Blue networks
Leaf & spine hybrid with Purple switches connected to both Red and Blue spines to support single homed devices
Leaf & spine Purple. Here, red and blue flows are connected to physically separate switches, but the switches are not identified as red and blue anymore. This is a converged network and an SDN controller is required to provide diverse paths flows to go to two different spines.

You can download the slides from here.

Watch now!

Speaker

Gerard Phillips
Systems Engineer
Arista Networks

Video: PTP Management and Media Flow Monitoring for All IP Infrastructures

Posted on 21st August 2019 by Adam K

Black and burst was always a ‘set and forget’ system. PTP, which replaces it, deserves active monitoring – and the same is true of your uncompressed media streams as we hear in this talk from the IP Showcase.

In professional essence-over-IP systems such as based on SMPTE ST 2110, timing needs to be rock solid. Thanks to asynchronous nature of IP many different flows can be carried across a network without having to be concerned with synchronization, but this presents a challenge in the production environment. To provide the necessary “genlock”, there is a need for a precise timing standard which is provided by SMPTE ST 2059 which defines the way broadcast signals relate to the IEEE 1588-2008 Precision Time Protocol, commonly referred to as PTPv2. This protocol is very different from analogue Black Burst and Tri-Level signals used in SDI world, so new tools and skills are required for fault finding.

In the first part of this presentation Thomas Gunkel from Skyline Communications focuses on the best practices to configure, monitor and manage PTP in an all-IP infrastructure covering the following:

PTP protocol vs reality (packet delay variation, network asymmetry, imperfect timestamping)
Increasing reliability of PTP (hardware timestamping, using QoS to prioritise PTP traffic, correcting timing intervals)
PTP device issues (grandmaster / boundary clock failure, loss of external reference, badly implemented BMCA)
PTP network issues (missing / corrupted event messages, increased packet delay variation, network asymmetry, multicast issues)
Automating PTP configuration (BMCA settings, messaging rate intervals, communication mode)
Automated PTP provisioning (detecting new PDP our devices using IS-04 or proprietary protocols, extracting end-to-end PTP topology with LLDP, applying standard PTP profiles)
PTP monitoring and control (monitor every single metric related to PTP like PTP offset, PTP mean path delay and multicast PTP network traffic for all grandmaster, master and slave devices, prevent slave devices from becoming master)

The second part of this video shows how to track uncompressed media flows in an ST 2110 IP-based media facility using a multi-layer approach and to how to pinpoint any potential issues using Network Monitoring System. Topics covered:

All IP flows vs SDI signals
Essentials for true orchestration (dynamically orchestrated resources and media services, monitoring / controlling infrastructure and media flows, automatic devices detection and provisioning)
Detecting issues (wrong DB entries for multicast essences, broadcast controller and SDN controller DBs out of sync, source not active, IGMP join / leave issues, SSM issues, network oversubscription)
Media flow tracking (reading cross point status from SDN controller, comparing this status with actual network topology, detecting “ghost” streams, using sFlow / NetFlow to track individual multicast flows)
Importance of true end-to-end SDN orchestration rather than SDN control (routing protocols which provides feedback)
All IP routing procedure (resolving multicast flow topology in combination with label management, checking source, checking destination route, presenting data for root cause analysis on each of these steps)

Watch now!

You can download the slides from here.

Speaker

Thomas Gunkel
Market Director Broadcast
Skyline Communications

Video: Scalable IP Architectures for Live Production and Playout

Posted on 29th March 2019 by Russell Trafford-Jones

For many building a good network for a 2110 or other media-over-IP standards is new and a bit scary. But if there’s one person who knows how to do it, it’s Arista’s Gerard Phillips who’s here to go through the basics and build up the network needed for a large and scalable network.

Scalability is the heart of this, because life does change – your company grows, technology pushes you from SD to HD to UHD etc. So you need to build scalability in from the beginning. Getting this right comes down to choosing the right hardware and having the right architecture.

Gerard looks at switch architecture and bandwidth both in the switch and of the network cables. He then looks towards ‘hub and spoke’ Vs monolithic switch design. What are the pros and cons to each and which is right for you?

SDN – Software Defined Networking – is also a key ingredient in such a network. This is where the routing decisions of the switch infrastructure is taken out of the switches because they have automatic and blinkered algorithms and takes it to a server which has a complete overview of the whole system. For a broadcaster who deals with critical signal chains – this is usually the best approach to give determinism and safety to the network.

PTP – Precision Time Protocol – provides the foundation of the 2110 standard and is therefore very important to studio installations being used to replace black and burst. What are the best ways to distribute this and how can you deal with redundancy?

These topics and more are all covered at this IP Showcase presentation from IBC 2018.

Watch now!

Speaker

Gerard Phillips
Systems Engineer,
Arista Networks

Video: P4 Tutorial

Posted on 4th March 2019 by Russell Trafford-Jones

P4 is a powerful programming language which runs on network switches themselves allowing realtime manipulation of the data traffic. In broadcast, this can be used to alter SMPTE 2110 video in real time as demonstrated by Thomas Edwards at the EBU Network Technology Seminar year and that can be seen in this short video. “This shows how even on an ethernet switch now, we can program it to make these switching decisions based on any header [including] the application layer of the broadcast data”

This video explains what P4 is and how it works taking us all the way from the core principles to ways of programming it and harnessing its power. Watching the beginning of the video is sufficient for most in order to get a feel for P4 and how it could be (and is) applied to broadcast.

The speakers, from Cisco and Barefoot Networks (who work with Thomas Edwards from Fox), cove these topics: