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As an observation (George please correct any obvious oops’s), I think recent BASE-T standards have tended to define the logical interface (e.g. XGMII), and leave the
real physical interface to the industry to figure out. Take a look at this presentation from 802.3bz (2.5G/5G BASE-T) -
http://www.ieee802.org/3/bz/public/may15/bains_3bz_01b_0515.pdf I would ask the question about where the physical interface should be defined, and how common would the requirements be across different industries and use cases. Regards Peter _______________________________________________
Peter Jones Cisco Systems
Principal Engineer 560 McCarthy Blvd. Campus Switching S/W Milpitas, CA, 95035 USA
Wrk: +1 408 525 6952 Mob: +1 408 315 8024
Email: petejone at cisco.com
Twitter: @petergjones LinkedIn: /in/petergjones _______________________________________________ From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi all, @Georg: You are right, occasionally I am an engineer and tend to describe all technical aspects to be sure no point is forgotten. So most of my proposal is maybe
important for the task force, but not for now. Only point I am missing in your proposal is the speed grad (10Mbps – or is this clear as we are working on a 10Mbps MDI) of the MII. So the objective would be
(including that the whole interface for sure is an “optional” solution like Ahmed pointed out): Define a optional 10Mbps MII (media independent interface) with reduced pin-count including an management interface. That this is only for stand-alone PHYs is clear to us. And that it shall work under industrial and automotive environmental conditions and that the reduced pin
count is intended to accommodate small package solutions of stand-alone PHYs (and as well simple µC as counter-part) and allow simple PCB layout is also straight forward. Regarding the automotive and industrial environmental conditions: Yes, MII-interfaces work, however, there is a lot of work to do to make them work properly in
automotive environment (as Claude mentioned: the radiation emission of MII or GMII is really a nigthmare sometimes, differential SGMII seems more easy often). As well we
have to consider automotive temperature grade and stuff like that when we define limit levels and tolerances for the signaling (but this is semiconductor manufacturers
task;-) to ensure the interface we define is conform in the whole temperature range… @Claude: I think for the beginning a discrete solution is interesting as well for sure (as we also have discrete Flexray PHYs…) Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: Claude R. Gauthier, Ph.D. [mailto:claude.gauthier@xxxxxxxxxxxxxxx]
Hi,
August 25, 2016 at 1:58 PM I think I see the source of your confusion. While the implementation of a physical MII is optional, there is always a reference point
defined for the interface between the MAC and PHY. Throughout IEEE Std 802.3, starting at 100M, that interface is a form of MII, and it is the logical definition point for a PHY, and physically optional to implement. In general, an interface we define internal to the port (that is, inside the box from the MDI) is optional, as one may choose to integrate all the rest of the functionality
within a chip or other closed system (such as multiple chips with proprietary internal interfaces). This happens all the time.
What is different in this project, and what I’m asking those in the group, is whether economic feasibility considerations are aided by us to defining (or adopting)
a reduced pin-count interface as part of this PHY project? Of course this is (at least nearly) irrelevant for integrated MAC/PHY chips; however, the issue did come up when discussing standalone PHYs with other participants. Again, of course, physically implementing
such an interface would be optional. I hope this clears it up. For those interested in how the standard reads on these interfaces elsewhere in 802.3, read on, otherwise you can skip it. -george First, the language in the standard isn’t
There are some places in 802.3 where the language is less than clear, and figures are labeled “MII is optional”, but, in fact, it is the
physical implementation and exposure of MII that is optional. (GMII is confused in the same way, in Clauses 34 & 35, the gigabit architecture clauses, GMII is NOT optional, but clause 40’s figure does have the “GMII is optional” statement – 36.1.5 makes this
clear, referring to “an optional physical instantiation” as GMII, and clause 40 (in 40.1.5) refers similarly that the physical implementation is optional, but the functionality is not). When looked at as a logical interface defined between 2 sublayers, the interface functionality can never be optional if they are to communicate.
You need a basis for communication between sublayers, if only to be able to define the standard (try to read clause 40 independent of the GMII). The language around the 10G interface (Clause 46, in 46.1) is a little more specific, where it says “Though
the XGMII is an optional interface, it is used extensively in this standard as a basis for specification.”
If we specify an interface, in my view, it would be optional to implement, because, of course, the logical interface is already defined. Any interface in 802.3 may or may not be physically exposed (and therefore may or may not be implemented as specified). Generally, there are many physically implementable
interfaces. Again, looking at 10G, the physically implemented interface can be XAUI (defined by IEEE standard), XFI (an MSA), or even XSGMII (proprietary). Similarly, gigabit PHYs are defined relative to GMII, but most phys either integrate the interface
functions internally, or use a proprietary interface like SGMII which maps the GMII functionality on an electrical interface.
I hope this has cleared it up, as much as it can – reviewing the language in multiple clauses of the 802.3-2015 standard, the nature of the MII (physical or logical,
optional or required) isn’t always entirely consistent or clear. However, for us, the issue here is whether economic feasibility considerations are aided by us to defining (or adopting) a reduced pin-count interface as part of this PHY project. -george From: Ahmad Chini [mailto:ahmad.chini@xxxxxxxxxxxx]
MII interface is OPTIONAL. Are we looking for a mandatory interface specification for 10SPE ? Thanks Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Ahmad – Thanks for jumping in, but I’m at a loss to see where you are going, other than to point out there are many proprietary MAC/PHY interfaces. Perhaps you can help clarify, and I’ll provide some background below. First, this is not a gigabit interface, so it is not GMII. Even so, GMII isn’t in Clause 40, which is the 1000BASE-T PCS/PMA. Physical implementation of the upstream
interfaces are optional for all the PMAs (because the MAC/PHY may be integrated as a chip, or may use a proprietary interface).
In order to meet our economic feasibility objective, there has been substantial discussion that reducing the cost of the device is important, and further, that pin
count related costs, such as package and test are a substantial issue. Given that we have only 2 signalling pins for the MDI side of the interface, using 18 for the MAC/PHY interface seems extreme. I haven’t heard anyone say we want to preclude standalone
PHY chips from meeting the economic feasibility criterion. The MAC/PHY interface specified for 100Mbps operation is MII. The MII as defined in Clause 22 has some 18 individual signals. There are various proprietary reduced
pin count MIIs – the question is whether we need to define one to meet the CSDs for this project. The options I see are below: (I’m not recommending any of these, but trying to drive the group to making a choice): -
Leave this to the implementer (has been done in the past, but, in this case, a solution is fairly important with regards to the CSDs in my opinion – and, in this
case, we’d need some justification for that, maybe a presentation on the variety of available MAC/PHY interfaces? -
Specify a reduced pin-count MII (could be based on an existing one…), this was the objective proposed – maybe included in the PHY technical/economic feasibility as
a factor for the pin count of the MAC/PHY interface -
Use the AUI (Clause 7), which is an option at 10Mbps, for the interface, which has 3 or 4 differential signals, power and ground (6 to 8 signalling pins, V+, V- and
Ground) but is very long in the tooth, uses 12V power and is designed for 78 ohm cable drivers.
Its just that it appears that from an economic feasibility point of view, at least for separate PHY chips, the MAC/PHY interface could be a significant issue. -george From: Ahmad Chini [mailto:ahmad.chini@xxxxxxxxxxxx]
Please see below diagram showing GMII is optional for 1000BASE-T. Many products in the market use reduced pin count interfaces (e.g. RGMII, SGMII, etc.)
not specified in Clause 40. Different products are made with different interfaces depending on use cases.
Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Stefan this is a good start. Generally, this is more detail than I’d like to see written in an objective (just my opinion). It is generally not a good idea to quote out environments unless it is expected to be an exposed interface, and it isn’t clear that the MAC interface, not exposed,
is going to the environment, so I’m unclear exactly what is meant “work under industrial and automotive environmental conditions.” (do you mean that the existing MAC/PHY interfaces do not work under these? If so, a presentation on the subject would be useful).
Usually PCB layouts and packages are out of scope as well (but everyone considers them in makingthe interface). I think the relevant part on package size/cost is the reduced pin count, so, with that in mind, how about: Define a reduced pin-count MAC/PHY interface including an optional management interface. (Geoff/Pat, others, “MAC/PHY interface” probably isn’t the right term, but I don’t have time to look it up right now. Please suggest the right term, assuming we
get consensus around this form.) -george From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi Georg, A first „quick and dirty“ proposal for an objective: Develop an specification for a 10Mbps MAC-Interface for industrial and automotive applications.
The MAC interface shall work under industrial and automotive environmental conditions and shall have reduced pin count to accommodate small package solutions and simple PCB layout solutions. The MAC interface shall include data line as well
as an optional management interface. -
Is this somehow what you expect? -
Is this doable under the intended study group/task force? Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Yong – you raise an interesting point about the MAC interface. With cost being a primary objective, and the line interface only requiring 1 pair, does it make sense to set as an objective defining a reduced pin count MAC/PHY
interface (to reduce test/package costs)? If so, how would you state it. From: Yong Kim [mailto:000006d33765285e-dmarc-request@xxxxxxxx]
I agree. And because I agree, I would like to share some observations. 1. CAN is channelized. With this I mean every payload for the CAN network is predefined -- analogy is telecom links. 2. Ethernet is packetized. With this I mean layers of headers define what payload means for each layer. 3. If the most inefficient Ethernet is comparable to CAN (roughly) - then it is good. This project should not be created to overlap with widely accepted and deployed technology. 4. Ethernet 10M would provide benefit where CAN falls short-- and CAN-FD as well -- providing much higher bandwidth. 5. And Ethernet provides network infrastructure for any practical speed link and allow them to all network together -- the reason for these use cases to move to Ethernet. And potentially eliminate overlay network segments
(BW aggregation) if admin domain allows for the aggregation.
August 25, 2016 at 1:24 PM MII interface is OPTIONAL. Are we looking for a mandatory interface specification for 10SPE ? Thanks Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Ahmad – Thanks for jumping in, but I’m at a loss to see where you are going, other than to point out there are many proprietary MAC/PHY interfaces. Perhaps you can help clarify, and I’ll provide some background below. First, this is not a gigabit interface, so it is not GMII. Even so, GMII isn’t in Clause 40, which is the 1000BASE-T PCS/PMA. Physical implementation of the upstream
interfaces are optional for all the PMAs (because the MAC/PHY may be integrated as a chip, or may use a proprietary interface).
In order to meet our economic feasibility objective, there has been substantial discussion that reducing the cost of the device is important, and further, that pin
count related costs, such as package and test are a substantial issue. Given that we have only 2 signalling pins for the MDI side of the interface, using 18 for the MAC/PHY interface seems extreme. I haven’t heard anyone say we want to preclude standalone
PHY chips from meeting the economic feasibility criterion. The MAC/PHY interface specified for 100Mbps operation is MII. The MII as defined in Clause 22 has some 18 individual signals. There are various proprietary reduced
pin count MIIs – the question is whether we need to define one to meet the CSDs for this project. The options I see are below: (I’m not recommending any of these, but trying to drive the group to making a choice): -
Leave this to the implementer (has been done in the past, but, in this case, a solution is fairly important with regards to the CSDs in my opinion – and, in this
case, we’d need some justification for that, maybe a presentation on the variety of available MAC/PHY interfaces? -
Specify a reduced pin-count MII (could be based on an existing one…), this was the objective proposed – maybe included in the PHY technical/economic feasibility as
a factor for the pin count of the MAC/PHY interface -
Use the AUI (Clause 7), which is an option at 10Mbps, for the interface, which has 3 or 4 differential signals, power and ground (6 to 8 signalling pins, V+, V- and
Ground) but is very long in the tooth, uses 12V power and is designed for 78 ohm cable drivers.
Its just that it appears that from an economic feasibility point of view, at least for separate PHY chips, the MAC/PHY interface could be a significant issue. -george From: Ahmad Chini [mailto:ahmad.chini@xxxxxxxxxxxx]
Please see below diagram showing GMII is optional for 1000BASE-T. Many products in the market use reduced pin count interfaces (e.g. RGMII, SGMII, etc.)
not specified in Clause 40. Different products are made with different interfaces depending on use cases.
Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Stefan this is a good start. Generally, this is more detail than I’d like to see written in an objective (just my opinion). It is generally not a good idea to quote out environments unless it is expected to be an exposed interface, and it isn’t clear that the MAC interface, not exposed,
is going to the environment, so I’m unclear exactly what is meant “work under industrial and automotive environmental conditions.” (do you mean that the existing MAC/PHY interfaces do not work under these? If so, a presentation on the subject would be useful).
Usually PCB layouts and packages are out of scope as well (but everyone considers them in makingthe interface). I think the relevant part on package size/cost is the reduced pin count, so, with that in mind, how about: Define a reduced pin-count MAC/PHY interface including an optional management interface. (Geoff/Pat, others, “MAC/PHY interface” probably isn’t the right term, but I don’t have time to look it up right now. Please suggest the right term, assuming we
get consensus around this form.) -george From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi Georg, A first „quick and dirty“ proposal for an objective: Develop an specification for a 10Mbps MAC-Interface for industrial and automotive applications.
The MAC interface shall work under industrial and automotive environmental conditions and shall have reduced pin count to accommodate small package solutions and simple PCB layout solutions. The MAC interface shall include data line as well
as an optional management interface. -
Is this somehow what you expect? -
Is this doable under the intended study group/task force? Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Yong – you raise an interesting point about the MAC interface. With cost being a primary objective, and the line interface only requiring 1 pair, does it make sense to set as an objective defining a reduced pin count MAC/PHY
interface (to reduce test/package costs)? If so, how would you state it. From: Yong Kim [mailto:000006d33765285e-dmarc-request@xxxxxxxx]
I agree. And because I agree, I would like to share some observations. 1. CAN is channelized. With this I mean every payload for the CAN network is predefined -- analogy is telecom links. 2. Ethernet is packetized. With this I mean layers of headers define what payload means for each layer. 3. If the most inefficient Ethernet is comparable to CAN (roughly) - then it is good. This project should not be created to overlap with widely accepted and deployed technology. 4. Ethernet 10M would provide benefit where CAN falls short-- and CAN-FD as well -- providing much higher bandwidth. 5. And Ethernet provides network infrastructure for any practical speed link and allow them to all network together -- the reason for these use cases to move to Ethernet. And potentially eliminate overlay network segments
(BW aggregation) if admin domain allows for the aggregation.
August 25, 2016 at 10:13 AM Ahmad – Thanks for jumping in, but I’m at a loss to see where you are going, other than to point out there are many proprietary MAC/PHY interfaces. Perhaps you can help clarify, and I’ll provide some background below. First, this is not a gigabit interface, so it is not GMII. Even so, GMII isn’t in Clause 40, which is the 1000BASE-T PCS/PMA. Physical implementation of the upstream
interfaces are optional for all the PMAs (because the MAC/PHY may be integrated as a chip, or may use a proprietary interface).
In order to meet our economic feasibility objective, there has been substantial discussion that reducing the cost of the device is important, and further, that pin
count related costs, such as package and test are a substantial issue. Given that we have only 2 signalling pins for the MDI side of the interface, using 18 for the MAC/PHY interface seems extreme. I haven’t heard anyone say we want to preclude standalone
PHY chips from meeting the economic feasibility criterion. The MAC/PHY interface specified for 100Mbps operation is MII. The MII as defined in Clause 22 has some 18 individual signals. There are various proprietary reduced
pin count MIIs – the question is whether we need to define one to meet the CSDs for this project. The options I see are below: (I’m not recommending any of these, but trying to drive the group to making a choice): -
Leave this to the implementer (has been done in the past, but, in this case, a solution is fairly important with regards to the CSDs in my opinion – and, in this
case, we’d need some justification for that, maybe a presentation on the variety of available MAC/PHY interfaces? -
Specify a reduced pin-count MII (could be based on an existing one…), this was the objective proposed – maybe included in the PHY technical/economic feasibility as
a factor for the pin count of the MAC/PHY interface -
Use the AUI (Clause 7), which is an option at 10Mbps, for the interface, which has 3 or 4 differential signals, power and ground (6 to 8 signalling pins, V+, V- and
Ground) but is very long in the tooth, uses 12V power and is designed for 78 ohm cable drivers.
Its just that it appears that from an economic feasibility point of view, at least for separate PHY chips, the MAC/PHY interface could be a significant issue. -george From: Ahmad Chini [mailto:ahmad.chini@xxxxxxxxxxxx]
Please see below diagram showing GMII is optional for 1000BASE-T. Many products in the market use reduced pin count interfaces (e.g. RGMII, SGMII, etc.)
not specified in Clause 40. Different products are made with different interfaces depending on use cases.
Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Stefan this is a good start. Generally, this is more detail than I’d like to see written in an objective (just my opinion). It is generally not a good idea to quote out environments unless it is expected to be an exposed interface, and it isn’t clear that the MAC interface, not exposed,
is going to the environment, so I’m unclear exactly what is meant “work under industrial and automotive environmental conditions.” (do you mean that the existing MAC/PHY interfaces do not work under these? If so, a presentation on the subject would be useful).
Usually PCB layouts and packages are out of scope as well (but everyone considers them in makingthe interface). I think the relevant part on package size/cost is the reduced pin count, so, with that in mind, how about: Define a reduced pin-count MAC/PHY interface including an optional management interface. (Geoff/Pat, others, “MAC/PHY interface” probably isn’t the right term, but I don’t have time to look it up right now. Please suggest the right term, assuming we
get consensus around this form.) -george From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi Georg, A first „quick and dirty“ proposal for an objective: Develop an specification for a 10Mbps MAC-Interface for industrial and automotive applications.
The MAC interface shall work under industrial and automotive environmental conditions and shall have reduced pin count to accommodate small package solutions and simple PCB layout solutions. The MAC interface shall include data line as well
as an optional management interface. -
Is this somehow what you expect? -
Is this doable under the intended study group/task force? Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Yong – you raise an interesting point about the MAC interface. With cost being a primary objective, and the line interface only requiring 1 pair, does it make sense to set as an objective defining a reduced pin count MAC/PHY
interface (to reduce test/package costs)? If so, how would you state it. From: Yong Kim [mailto:000006d33765285e-dmarc-request@xxxxxxxx]
I agree. And because I agree, I would like to share some observations. 1. CAN is channelized. With this I mean every payload for the CAN network is predefined -- analogy is telecom links. 2. Ethernet is packetized. With this I mean layers of headers define what payload means for each layer. 3. If the most inefficient Ethernet is comparable to CAN (roughly) - then it is good. This project should not be created to overlap with widely accepted and deployed technology. 4. Ethernet 10M would provide benefit where CAN falls short-- and CAN-FD as well -- providing much higher bandwidth. 5. And Ethernet provides network infrastructure for any practical speed link and allow them to all network together -- the reason for these use cases to move to Ethernet. And potentially eliminate overlay network segments
(BW aggregation) if admin domain allows for the aggregation.
August 25, 2016 at 9:42 AM Please see below diagram showing GMII is optional for 1000BASE-T. Many products in the market use reduced pin count interfaces (e.g. RGMII, SGMII, etc.)
not specified in Clause 40. Different products are made with different interfaces depending on use cases.
Ahmad From: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Stefan this is a good start. Generally, this is more detail than I’d like to see written in an objective (just my opinion). It is generally not a good idea to quote out environments unless it is expected to be an exposed interface, and it isn’t clear that the MAC interface, not exposed,
is going to the environment, so I’m unclear exactly what is meant “work under industrial and automotive environmental conditions.” (do you mean that the existing MAC/PHY interfaces do not work under these? If so, a presentation on the subject would be useful).
Usually PCB layouts and packages are out of scope as well (but everyone considers them in makingthe interface). I think the relevant part on package size/cost is the reduced pin count, so, with that in mind, how about: Define a reduced pin-count MAC/PHY interface including an optional management interface. (Geoff/Pat, others, “MAC/PHY interface” probably isn’t the right term, but I don’t have time to look it up right now. Please suggest the right term, assuming we
get consensus around this form.) -george From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi Georg, A first „quick and dirty“ proposal for an objective: Develop an specification for a 10Mbps MAC-Interface for industrial and automotive applications.
The MAC interface shall work under industrial and automotive environmental conditions and shall have reduced pin count to accommodate small package solutions and simple PCB layout solutions. The MAC interface shall include data line as well
as an optional management interface. -
Is this somehow what you expect? -
Is this doable under the intended study group/task force? Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Yong – you raise an interesting point about the MAC interface. With cost being a primary objective, and the line interface only requiring 1 pair, does it make sense to set as an objective defining a reduced pin count MAC/PHY
interface (to reduce test/package costs)? If so, how would you state it. From: Yong Kim [mailto:000006d33765285e-dmarc-request@xxxxxxxx]
I agree. And because I agree, I would like to share some observations. 1. CAN is channelized. With this I mean every payload for the CAN network is predefined -- analogy is telecom links. 2. Ethernet is packetized. With this I mean layers of headers define what payload means for each layer. 3. If the most inefficient Ethernet is comparable to CAN (roughly) - then it is good. This project should not be created to overlap with widely accepted and deployed technology. 4. Ethernet 10M would provide benefit where CAN falls short-- and CAN-FD as well -- providing much higher bandwidth. 5. And Ethernet provides network infrastructure for any practical speed link and allow them to all network together -- the reason for these use cases to move to Ethernet. And potentially eliminate overlay network segments
(BW aggregation) if admin domain allows for the aggregation.
August 25, 2016 at 9:14 AM Stefan this is a good start. Generally, this is more detail than I’d like to see written in an objective (just my opinion). It is generally not a good idea to quote out environments unless it is expected to be an exposed interface, and it isn’t clear that the MAC interface, not exposed,
is going to the environment, so I’m unclear exactly what is meant “work under industrial and automotive environmental conditions.” (do you mean that the existing MAC/PHY interfaces do not work under these? If so, a presentation on the subject would be useful).
Usually PCB layouts and packages are out of scope as well (but everyone considers them in makingthe interface). I think the relevant part on package size/cost is the reduced pin count, so, with that in mind, how about: Define a reduced pin-count MAC/PHY interface including an optional management interface. (Geoff/Pat, others, “MAC/PHY interface” probably isn’t the right term, but I don’t have time to look it up right now. Please suggest the right term, assuming we
get consensus around this form.) -george From: Stefan Buntz [mailto:stefan.buntz@xxxxxxxxxxx]
Hi Georg, A first „quick and dirty“ proposal for an objective: Develop an specification for a 10Mbps MAC-Interface for industrial and automotive applications.
The MAC interface shall work under industrial and automotive environmental conditions and shall have reduced pin count to accommodate small package solutions and simple PCB layout solutions. The MAC interface shall include data line as well
as an optional management interface. -
Is this somehow what you expect? -
Is this doable under the intended study group/task force? Regards, Stefan ------------------------------------------ Stefan Buntz Mercedes-Benz Cars Development, Daimler AG Group Research & Advanced Engineering Safeguarding Hard & Software
HPC: U059 – Dep.: RD/EEQ Phone: +49 731 505-2089
Mobil: +49 176 30 90 51 44
Fax: +49 711 305 216 45 95
E-Mail:
stefan.buntz@xxxxxxxxxxx Address for visitors: Buildung 10 Room 3.2.022 Wilhelm-Runge-Str. 11 D-89081 Ulm Germany ------------------------------------------ Von: George Zimmerman [mailto:george@xxxxxxxxxxxxxxxxxxxx]
Yong – you raise an interesting point about the MAC interface. With cost being a primary objective, and the line interface only requiring 1 pair, does it make sense to set as an objective defining a reduced pin count MAC/PHY
interface (to reduce test/package costs)? If so, how would you state it. From: Yong Kim [mailto:000006d33765285e-dmarc-request@xxxxxxxx]
I agree. And because I agree, I would like to share some observations. 1. CAN is channelized. With this I mean every payload for the CAN network is predefined -- analogy is telecom links. 2. Ethernet is packetized. With this I mean layers of headers define what payload means for each layer. 3. If the most inefficient Ethernet is comparable to CAN (roughly) - then it is good. This project should not be created to overlap with widely accepted and deployed technology. 4. Ethernet 10M would provide benefit where CAN falls short-- and CAN-FD as well -- providing much higher bandwidth. 5. And Ethernet provides network infrastructure for any practical speed link and allow them to all network together -- the reason for these use cases to move to Ethernet. And potentially eliminate overlay network segments
(BW aggregation) if admin domain allows for the aggregation.
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