Professional Audio / Video over Ethernet, a completely new approach
This article will focus on a fundamentally new technology for the transfer of professional digital AV - “Audio Video Bridging”.
Currently, all other technologies (CobraNET, EtherSound, etc.) are proprietary (read-paid) or generally connected to Ethernet very remotely.
AVB is a family of protocols developed by IEEE (the same institute as standardized Ethernet itself), i.e. requiring no royalties.
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For those who are too lazy to read, you can simply view the presentation, those who are interested in the details and comments please under the cat.
In the modern ProAV world, analog connections still prevail. Which in turn can transmit one stream over a single cable.
This approach leads to the fact that the cable infrastructure becomes redundant and very expensive, both at the installation stage and in future maintenance.
And the existing proprietary digitalization solutions (CobraNET, EtherSound, etc.) do not solve the problem radically (scaling, compatibility, ...).
But interest creates demand, and such giants of the IT industry as Broadcom, Cisco, Harman, Intel, Xilinx founded the AVNU Alliance, which already includes 50 companies.
This non-profit organization is engaged in the development, promotion, certification for compatibility of AVB products.
Since IEEE 802.1 is engaged in standardization, it is not surprising that the principle of AVB and DCB (Data Center Bridging) work is very similar (they develop neighboring teams of the same working group).
The AVB protocol family includes:
1. 802.1AS (Timing and Synchronization (gPTP) - Allows you to synchronize streams with an accuracy of 0.5 µs within 7 hops. The idea of the protocol is taken from the IEEE 1588v2 standard
For the operation of this protocol, hardware support is necessary, since a “time-stamp” must be affixed to the port,
Therefore, the equipment of some manufacturers using their own ASICs will not support AVB even after updating the software.
2. 802.1Qav (Traffic Shaping) - Traffic profiling allows you to work within maximum delay for “class A” packets (system pro) and “class B” (user) - 2 and 50 ms, respectively, as well as traffic smoothing for eliminate potential losses.
3. 802.1Qat (Stream Reservation Protocol (SRP) - Dynamic reservation of up to 75% of the link resource for streaming. Two upper QoS profiles are used
4. 802.1BA (Audio Video Bridging (AVB) Systems) - Determination of AVB devices and their identification in the network (speed and duplex of link operation, support for 802.1 AS, delay calculation, confirmation of resource reservation)
The remaining protocols are equally important additions for the full operation of AVB systems.
IEEE 1722, 1733 - Protocols describing transport for AVB networks
IEEE 1722.1 * - Protocol for detection, monitoring, numbering, devices operating in 1722
However, only the latter is still the Draft version, the other standards are accepted.
The AVB holistic system consists of the following parts:
• Endpoint - are essentially “AVB - gateway” which carry out ADC and DAC conversion with the necessary formatting, can be
a. Talker (microphone, camera, mixer, ...)
b. Listener (speakers, monitor, remote, ...)
c. Both (mixer, remote, ...)
• AVB Bridge - switch supporting AVB
• Controller - a device or software with the help of which all “Endpoint” and their flows are detected, mapped to the operator for making a decision on their switching.
Below is a block diagram of the inclusions of a working stand.
The benefits of using AVB systems are many:
- no vendor-lock
- sharing AVB, and non-AVB devices on the same network
- increased throughput
- flexible scaling
- standard SCS
- simplified installation and troubleshooting
- use of PoE
- and much more
As the reverse side of the medal, it is probably worth mentioning that for the AVB-system to work, all streams should constantly be broadcast to the network.
But given the low cost of Ethernet transport, this is not a big problem. Especially when you consider the math for the bandwidth of one link:
Single channel stream capacity (24 bit 48 kHz Audio) = ~ 6 MB / stream
1000 MB (1GB) * 0.75 / ~ 6 MB # reserved 75% of the link
= ~ 125 streams (actually 122)
- Each stereo / AES3 channel stream = ~ 8 MB / stream
1000 MB * 0.75 / ~ 8 MB
= ~ 94 streams (really 97)
Since the relevance of this topic is not in doubt, many members of the AVNU Alliance have already released commercial samples of AVB products, the number of implemented projects is constantly growing despite the youth of the technology.
If the network parts are touched, then AVB from LABx, BSS / Netgear and Extreme Networks AVB support switches are available on the market (the most complete line). Therefore, choosing Extreme Networks switches you invest in the future of your company's network !
Extreme Networks Authorized Training Courses
MUK-Service - all types of IT repair: warranty, non-warranty repair, sale of spare parts, contract service
Currently, all other technologies (CobraNET, EtherSound, etc.) are proprietary (read-paid) or generally connected to Ethernet very remotely.
AVB is a family of protocols developed by IEEE (the same institute as standardized Ethernet itself), i.e. requiring no royalties.
')
For those who are too lazy to read, you can simply view the presentation, those who are interested in the details and comments please under the cat.
In the modern ProAV world, analog connections still prevail. Which in turn can transmit one stream over a single cable.
This approach leads to the fact that the cable infrastructure becomes redundant and very expensive, both at the installation stage and in future maintenance.
And the existing proprietary digitalization solutions (CobraNET, EtherSound, etc.) do not solve the problem radically (scaling, compatibility, ...).
But interest creates demand, and such giants of the IT industry as Broadcom, Cisco, Harman, Intel, Xilinx founded the AVNU Alliance, which already includes 50 companies.
This non-profit organization is engaged in the development, promotion, certification for compatibility of AVB products.
Since IEEE 802.1 is engaged in standardization, it is not surprising that the principle of AVB and DCB (Data Center Bridging) work is very similar (they develop neighboring teams of the same working group).
The AVB protocol family includes:
1. 802.1AS (Timing and Synchronization (gPTP) - Allows you to synchronize streams with an accuracy of 0.5 µs within 7 hops. The idea of the protocol is taken from the IEEE 1588v2 standard
For the operation of this protocol, hardware support is necessary, since a “time-stamp” must be affixed to the port,
Therefore, the equipment of some manufacturers using their own ASICs will not support AVB even after updating the software.
2. 802.1Qav (Traffic Shaping) - Traffic profiling allows you to work within maximum delay for “class A” packets (system pro) and “class B” (user) - 2 and 50 ms, respectively, as well as traffic smoothing for eliminate potential losses.
3. 802.1Qat (Stream Reservation Protocol (SRP) - Dynamic reservation of up to 75% of the link resource for streaming. Two upper QoS profiles are used
4. 802.1BA (Audio Video Bridging (AVB) Systems) - Determination of AVB devices and their identification in the network (speed and duplex of link operation, support for 802.1 AS, delay calculation, confirmation of resource reservation)
The remaining protocols are equally important additions for the full operation of AVB systems.
IEEE 1722, 1733 - Protocols describing transport for AVB networks
IEEE 1722.1 * - Protocol for detection, monitoring, numbering, devices operating in 1722
However, only the latter is still the Draft version, the other standards are accepted.
The AVB holistic system consists of the following parts:
• Endpoint - are essentially “AVB - gateway” which carry out ADC and DAC conversion with the necessary formatting, can be
a. Talker (microphone, camera, mixer, ...)
b. Listener (speakers, monitor, remote, ...)
c. Both (mixer, remote, ...)
• AVB Bridge - switch supporting AVB
• Controller - a device or software with the help of which all “Endpoint” and their flows are detected, mapped to the operator for making a decision on their switching.
Below is a block diagram of the inclusions of a working stand.
The benefits of using AVB systems are many:
- no vendor-lock
- sharing AVB, and non-AVB devices on the same network
- increased throughput
- flexible scaling
- standard SCS
- simplified installation and troubleshooting
- use of PoE
- and much more
As the reverse side of the medal, it is probably worth mentioning that for the AVB-system to work, all streams should constantly be broadcast to the network.
But given the low cost of Ethernet transport, this is not a big problem. Especially when you consider the math for the bandwidth of one link:
Single channel stream capacity (24 bit 48 kHz Audio) = ~ 6 MB / stream
1000 MB (1GB) * 0.75 / ~ 6 MB # reserved 75% of the link
= ~ 125 streams (actually 122)
- Each stereo / AES3 channel stream = ~ 8 MB / stream
1000 MB * 0.75 / ~ 8 MB
= ~ 94 streams (really 97)
Since the relevance of this topic is not in doubt, many members of the AVNU Alliance have already released commercial samples of AVB products, the number of implemented projects is constantly growing despite the youth of the technology.
If the network parts are touched, then AVB from LABx, BSS / Netgear and Extreme Networks AVB support switches are available on the market (the most complete line). Therefore, choosing Extreme Networks switches you invest in the future of your company's network !
Extreme Networks Authorized Training Courses
MUK-Service - all types of IT repair: warranty, non-warranty repair, sale of spare parts, contract service
Source: https://habr.com/ru/post/174153/
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