[Rfid] Management vs. Control vs. Data
Margaret Wasserman <margaret@thingmagic.com> Fri, 22 July 2005 15:57 UTC
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Date: Fri, 22 Jul 2005 11:56:31 -0400
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From: Margaret Wasserman <margaret@thingmagic.com>
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Subject: [Rfid] Management vs. Control vs. Data
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Another thought on our RFID reader control protocol (whatever we decide to name it)... It seems to me that some of our discussions are mixing together the control plane (or control functions) and the data plane (or data functions). We also seem to be combining the concepts of single reader control and multi-reader control (which includes concepts such as synchronization). On some level, the management plane also seems to be conflated. I think that we should be very clear about defining/understanding the functional blocks to in our RFID network architecture, and I think that we need to understand the relationships between those blocks and the requirements for each of them _before_ we decide that SLRRP is the correct starting place for an RFID reader control protocol. The SLRRP protocol seems to make some basic assumptions in this area that I question. It seems to assume four things: (1) That there will be a one-to-many mapping between RFID controllers and RFID readers. In other words, that only one controller (whether it is running on the reader, a controller device, a piece of networking equipment or a server) will be controlling a given reader at any point in time. Given the nature of RFID readers, this _might_ be reasonable, although I would welcome alternatives. (This is a control plane function.) (2) That single reader control functions and multi-reader control functions (such as synchronization) will both be controlled by the same controller functional unit. (Another control plane function.) (3) That the same functional unit that is controlling the reader will be the only first-line consumer for all of the readers' tag data and other events. (This is a data plane function.) AND (3) That the same functional unit will serve as the arbiter for all management/monitoring requests (this is a Management plane function.) Actually, I am not sure that this is really intended in SLRRP, but it is implied by this text in the proposed charter: We envision a typical RFID deployment comprising of a network of RFID readers controlled by one or more reader network controller elements (which may be software in a server, RFID reader, control blade of a router/switch, or a standalone device). These controller elements in turn are connected to hosts/servers running client applications that ultimately consume the acquired tag data and management applications that monitor the operation of the reader network. Do these three restrictions/conflations actually make sense? I understand why (perhaps?) there should be a single controller that is taking requests from multiple applications and determining what RFID functions a specific reader should perform in order to carry out those requests. This code could run on a smart reader itself, or on external node that controls one or more less-smart readers. However, I see no reason why this one controller should be a choke point for the data plane. The controller could configure the reader to know about one or more consumers and set filters that indicate what data should be sent to those consumers. Then, the reader could transmit the data to the consumers directly. This removes a third-party dependency on the controller in order for a reader that is operating autonomously (perhaps as configured by the controller) to send its data to a set of consumers. I also understand that there might be a multi-reader coordination function that would generally run external to any of the readers. Although this is also a control-plane function, it might be better to break the single-reader control and multi-reader control into two separate functional boxes in our architecture, so that they can run in independent locations. What do others think? And, I certainly don't understand why an RFID controller should be involved in the management/monitoring of a reader -- I should be able to use a commercial management station (like Tivoli or HP Open View) to monitor the health of my readers and the state of their RFID functions via SNMP or other protocols without involving any third party. Right? For much-less-smart readers that are not capable of supporting SNMP, a proxy could run somewhere, I suppose... But this doesn't have to be the same functional unit as the controller. Are there specific reasons why the SLRRP architecture has a single controller handle the control, data and management functions? Breaking these things into separate functional units in our architecture would not stop someone from running all of them on a single CPU, but it would allow us the flexibility to place different types of functionality at different places in the RFID network. Margaret _______________________________________________ Rfid mailing list Rfid@lists.ietf.org https://www1.ietf.org/mailman/listinfo/rfid
- [Rfid] Management vs. Control vs. Data Margaret Wasserman