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A Vastly Simpler Alternative for P802.11ak. Authors:. Date: 2014-04-07. Abstract.
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A Vastly Simpler Alternative for P802.11ak Authors: • Date:2014-04-07 Norman Finn, Cisco Systems
Abstract • Methods for accomplishing the primary goals of P802.11ak are presented that are vastly simpler than the current working proposal, defined in 11-14/0454r1. This simplicity is obtained at the expense of removing the capability of directing a single transmission to multiple bridge/stations. Norman Finn, Cisco Systems
Cost / Benefit Tradeoffs • Absolute costs (e.g., in dollars) are prohibited from being discussed in IEEE 802. • Relative costs, e.g., “Plan A appears to me to be more costly to implement that Plan B” are allowed. • This submission discusses relative costs, not absolute costs. Norman Finn, Cisco Systems
The current P802.11ak plan,as expressed in 11-14/0454-r1 • The current working text for P802.11ak includes, in every frame transmitted by an AP on an 11ak BSS, a list of AIDs. • The current working text for P802.11ak includes negotiation methods, to be used during the association of a non-AP station to an AP station, to indicate the level of 11ak compatibility of both stations. • These features have been invented so that the AP can indicate which non-AP stations are supposed to accept the PDU, and which are to discard it, when the PDU is multicast to some number of non-AP stations. Norman Finn, Cisco Systems
Suppose, instead, we … • Requirethe use of the 4-address format in P802.11ak, without changing the meanings of the four addresses (Receiver, Transmitter, Destination, and Source) in any way; • State, in P802.11ak, that an 11ak-capable AP sends frames to and receives them from an 11ak-mode non-AP station only in 4-address format, and only using unicast Receiver addresses; and • Let the use of an A-MSDU, and/or an A-MPDU be decided by the usual rules, and be driven by the link level aggregation needs. Norman Finn, Cisco Systems
Then, … • We still need a way to indicate, during association, that the stations want to operate in 11ak mode. But … • We don’t need to process AID lists. • We don’t need a new format for A-MSDUs. • We can use A-MSDU + A-MPDUs normally for their intended functions. • We don’t need to place 11ak-mode non-AP stations in a separate BSS from existing 3-address non-AP stations. • And, most importantly, this standard might actually be implemented. Norman Finn, Cisco Systems
What aboutmulticast AP transmissions? • Yes, that’s what 802.1 asked for. But … • At low speeds, bridges attached to non-AP stations are not useful. • They don’t work now, and new products operate at higher speeds. • Multicast has a high error rate, and uses lower data rates. • High complexity required in AP to gather frames from different queues to go to the same destination sets. • High complexity required in receiver to decide whether to receive, especially when most traffic is Unicast. Norman Finn, Cisco Systems
References • Current proposed text for 802.11ak is at: https://mentor.ieee.org/802.11/dcn/14/11-14-0454-01-00ak-some-11ak-text.docx Norman Finn, Cisco Systems