... | ... | @@ -66,7 +66,7 @@ achieved. |
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Bridgaes can correct time interval measurements using the
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grandmaster frequency ratio conveyed in Follow\_UP's TLV, p22 of
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\[2\]). Optional features \[1\]: IEEE 802.1AS bridges and end
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stations are not be required to physically syntonize (using
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stations are not required to physically syntonize (using
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frequency ratio) their frequency to the GM frequency (though
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they are be allowed to do this).
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- performance requirement, Annex B of \[2\]:
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... | ... | @@ -135,7 +135,7 @@ achieved. |
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(determined during Ethernet link establishment) and the link delay
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measurements done by IEEE 802.1AS
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## **AVB *Gen2***
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## **AVB *Gen2*** (AVBg2)
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The AVB Gen2 is developed to further enhance AVB's performance. The
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requirements for AVB Gen2 are defined not only by Audio/Video industry
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... | ... | @@ -146,12 +146,12 @@ Improvements to AVB Gen 1: |
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- P802.1ASbt: Timing and Synchronization for Time-Sensitive
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Applications
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- P802.1Qbv : Enhancements for Scheduled Traffic
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New ideas:
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- P802.1Qbu : Frame Preemption
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There are some ideas that will be potentially included into AVB
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Gen2:
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- new topology resolution
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- P802.1Qbv : Enhancements for Scheduled Traffic
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New ideas:
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- P802.1Qbu : Frame Preemption
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- Static/dynamic redundancy (potentially included into AVB Gen2)
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### Requirements for AVB Gen 2
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... | ... | @@ -197,8 +197,6 @@ Improvements to AVB Gen 1: |
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- traffic characteristics: "control data" size (payload):
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typical \<300 bytes, small burst of frames at known regular
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intervals (e.g. a 40us long burst every 125 us)
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- General Motors
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([see](http://www.ieee802.org/1/files/public/docs2012/new-avb-jochim-redundancy-requirements-GM-perspective-AVB2-0312.pdf))
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- new AVB Gen2 features should be optional [General Motors,
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pages 43](http://www.ieee802.org/1/files/public/docs2012/new-avb-jochim-redundancy-requirements-GM-perspective-AVB2-0312.pdf))
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... | ... | @@ -386,11 +384,13 @@ Both solutions, WR and AVB, work only over WR/AVB-compatible devices but |
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provide interoperability with standard Ethernet.
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The main difference is the usage of SyncE and single fiber in WR. AVBg2
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bridges will have to be time aware, so will probably syntonize to
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grandmaster's frequency using Sync Messages and will need to synchronize
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to grandmaster, like WR (AVBg1 bridges are transparent and syntonize
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optionally). The efforts to support network redundancy and speed-up
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reconfiguration seem to be inline in WR and AVB. (**ToFinish**)
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bridges will have to be time aware but this does not translate into
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syntonization. WR requires all WR-devices to be syntonized which is an
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option in AVB. The efforts to support network redundancy and speed-up
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reconfiguration seem to be inline in WR and AVB. There is an apparent
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need in AVBg2 to find a solution for (semi-)automatic link asymmetry
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compensation. Although WR provides solution for this, it does not need
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to be favored by AVBg2 (due to single fiber usage).
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### Critical-data-wise
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... | ... | |