AVB Endpoints vs Network Nodes

Today we see what are the differences between an AVB endpoint (which are the AVB talkers and AVB listeners) versus an AVB compliant Network node (which connects those end-points to each other in an AVB network).

AVB is an Ethernet based Layer-2 Audio-Video bridging technology (from a Network perspective), however, any vanilla (or even high-end) Ethernet switch cannot be used to connect AVB devices, as it will not be able to provide the required Quality-of-Service though the network or be able to guarantee reservations required by AVB to operate. Let us first see how an AVB enabled Ethernet-switch is different

Normal Ethernet Switch AVB enabled Ethernet Switch
Provides Ethernet Switching capability
Can have 2 or more ports with different port-speeds
Provides MAC learning, switching, filtering etc
Supports VLANs, priorities & Multicast capability
Basically provides Ethernet Layer-2 connectivity
It needs to provide all the features
that a normal Ethernet Switch provides
N/A Needs to provide stream delivery guarantee
Has to synchronise and transfer clock
Support Stream Reservation protocol
Deliver Audio/Video payload without drops
Keep the latency within required margin
Communicate with other AVB nodes

As we see above, an AVB-enabled network gear is specialized in the way it operates and communicates with its peers. Now lets us see, how an AVB end-point is different from an AVB switch itself.

content-security

...that's not all folks!

To continue reading the article, please Login/Register

(c) AVChrono 2021, All Rights Reserved

PTP Master Clocks and GMs

PTP (Precision Time Protocol) Networks are Timing/Clock hierarchies that can support multiple Master(s) and Grand-Master(s) as the source of accurate time. Each clock-node "advertises' its capability (like clock accuracy, its source of time, it own variance etc) into the network.

These PTP networks could be Ethernet, or use IP/UDP as transport protocols or even MPLS. There are implementations and design considerations to support IEEE 1588 on Wireless links too. And then, we have DeviceNet, ControlNet and ProfiNet etc that support PTP.

As we have seen in previous articles, the PTP messages themselves could be transported in a Multicast mode or use Unicast communication, and the recent standard also supports Mixed mode (Unicast+Multicast)

content-security

...that's not all folks!

To continue reading the article, please Login/Register

(c) AVChrono 2021, All Rights Reserved

You cannot copy content of this page
%d bloggers like this: