LLD kommt nicht for free sondern benötigt signaling zwischen CMTS und CPEs, dementsprechend verringert sich die verfügbare Bandbreite mit jedem CPE mehr im Segment, daher lässt sich das nicht Sinnvoll einsetzen in großen Segmenten.
DOCSIS 4.0 ESD Demo
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Bitte gib bei der Erstellung eines Threads im Feld „Präfix“ an, ob du Kunde von Vodafone Kabel Deutschland („[VFKD]“) oder von Vodafone West („[VF West]“) bist.
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Re: DOCSIS 4.0 ESD Demo
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Re: DOCSIS 4.0 ESD Demo
Und wie viel Overhead denkst du verursacht irgendein signaling bei LLD sodass es die derzeitigen Segmente an ihre Grenzen bringen würde? Und welches signaling meinst du überhaupt, könntest du vielleicht die korrekten Begriffe wie sie im Standard verwendet werden ebenfalls verwenden, dann weiß man auch was du meinst.
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Re: DOCSIS 4.0 ESD Demo
Bei Segment größen von 1200+ und den im PDF angestrebten Latenzen von ~1ms mehr als ein Segment an upload bereitstellt.Flole hat geschrieben: ↑09.06.2022, 15:56 Und wie viel Overhead denkst du verursacht irgendein signaling bei LLD sodass es die derzeitigen Segmente an ihre Grenzen bringen würde? Und welches signaling meinst du überhaupt, könntest du vielleicht die korrekten Begriffe wie sie im Standard verwendet werden ebenfalls verwenden, dann weiß man auch was du meinst.
Also LLD mit PGS
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Re: DOCSIS 4.0 ESD Demo
Ein Segment stellt über 200Mbit/s an Upload bereit. Und das alles willst du nur für signaling benutzen? PGS zum Beispiel wäre ja aber auch kein signaling mehr....
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Re: DOCSIS 4.0 ESD Demo
There is some amount of overhead involved with PGS, because of the unsolicited nature of the grants (the modem may receive more grants than it can use = wasted). PGS is not a fixed and static thing, though. It is configurable by the operator (target latency). The CMTS can also optimize it, by looking at the traffic pattern from the modem.
PGS is optional. LLD can be activated without it (you cannot reach 1ms without it, though).
PGS is optional. LLD can be activated without it (you cannot reach 1ms without it, though).
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Re: DOCSIS 4.0 ESD Demo
But that's not signaling traffic, PGS does not cause noticeable signaling traffic. Not to mention that proactively assigned timeslots will not need a Request-Cycle so that overhead is reduced there.
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Re: DOCSIS 4.0 ESD Demo
Yes, the bandwidth requests from the modem will be reduced a bit, but the amount of bandwidth needed for that is tiny compared to how much wasted grants can eat up.
DOCSIS has always (until now) been about using the bandwidth as optimally as possible (many modems must share not that much upstream bandwidth). For example, contention slots, where the modem can request bandwidth, is a shared ressource (bandwidth efficient). It also mean that these requests can collide with requests from other modems, so they must be retransmitted (all in the name of saving bandwidth).
DOCSIS has always (until now) been about using the bandwidth as optimally as possible (many modems must share not that much upstream bandwidth). For example, contention slots, where the modem can request bandwidth, is a shared ressource (bandwidth efficient). It also mean that these requests can collide with requests from other modems, so they must be retransmitted (all in the name of saving bandwidth).
Zuletzt geändert von denunge am 10.06.2022, 09:31, insgesamt 3-mal geändert.
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Re: DOCSIS 4.0 ESD Demo
GPON as it's been used and will be used for years to come cannot reach 1 ms either. It's consumer grade infrastructure we talk about. It's all about "good enough" and cost efficiency there. And that's why I assume docsis is just in the middle of its lifespan with another ≈20 years ahead.denunge hat geschrieben: ↑10.06.2022, 08:10 There is some amount of overhead involved with PGS, because of the unsolicited nature of the grants (the modem may receive more grants than it can use = wasted). PGS is not a fixed and static thing, though. It is configurable by the operator (target latency). The CMTS can also optimize it, by looking at the traffic pattern from the modem.
PGS is optional. LLD can be activated without it (you cannot reach 1ms without it, though).
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Re: DOCSIS 4.0 ESD Demo
To compare DOCSIS to GPON... GPON has always (until now) had more upstream bandwith than DOCSIS systems, and with fewer customers to share it, so they could implement a scheduling system from day 1 that was more latency efficient.
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Re: DOCSIS 4.0 ESD Demo
Both are on the market and compete for customers that do compare. I for one have ftth access in my home, but I don't use it, docsis is enough for me (not enough as in I feel like giving up on something, but go for the eco option anyway, like economy class in a plane, but it has literally all I need).
The comparison is a market reality for customers. I just don't pay a "ftth premium" just like that.
The comparison is a market reality for customers. I just don't pay a "ftth premium" just like that.