Tengfei, We are putting together different pieces of the stack contained in many document written by different organizations. It's of course a bit confusing, and it's great that so many eyes are looking so closely at it. You're not "making trouble" in any way, please keep on doing exactly what you are doing :-) Thomas
On Thursday, June 25, 2015, Tengfei Chang <[email protected]> wrote: > Jonathan, Simon, > > After the discussion on the format order of ieee802.15.4, I believe now > the format that proposed by Simon is right. > > The text I copied from IEEE802.15.4 didn't cover the case of 2.4GHz > O-QPSK radio chip, which will transmit the data by bits group, not bit by > bit. Thanks Thomas for clarifying this! > > Sorry if I made some trouble on this issue! > > Tengfei > > > > On Thu, Jun 25, 2015 at 6:41 AM, Thomas Watteyne < > [email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: > >> +1 >> Thanks >> >> On Thu, Jun 25, 2015 at 12:40 AM, Jonathan Hui <[email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: >> >>> There are a number of examples in Annex C in IEEE 802.15.4-2011 that >>> express IEEE 802.15.4 frames as a a sequence of hex bytes. For example, >>> Section C.2.1.1 has the following text: >>> >>> Secured beacon frame: >>> 08 D0 84 21 43 01 00 00 00 00 48 DE AC || 02 05 00 00 00 || 55 CF 00 >>> 00 51 52 53 54 22 3B C1 EC 84 1A B5 53. >>> >>> It doesn't take much to figure out that: >>> 1) The bytes are listed in little-endian order from left to right >>> 2) Within each byte, the bits are such that 0x01 represents bit 0 being >>> set to 1 and 0x80 represents bit 7 being set to 1. >>> >>> We should follow the convention already used in IEEE 802.15.4 specs. >>> >>> -- >>> Jonathan Hui >>> >>> >>> On Wed, Jun 24, 2015 at 3:28 PM, Thomas Watteyne < >>> [email protected] >>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: >>> >>>> To make sure we're on the same page, below are two examples of the >>>> bit-and-byte ordering in the IEEE802.15.4e-2011 and IEEE802.15.4e-2012 >>>> standard, as I read them. >>>> Please indicate whether this is what you understood. >>>> @JonathanHui, I have IEEE802.15.4-2011 and IEEE802,15,4e-2012 in front >>>> of me. Which Annexes are your referring to that contain such examples? >>>> Thomas >>>> >>>> ---- >>>> >>>> *Example 1*. Frame Control Field >>>> >>>> Fig 36 "Format of the Frame Control field" of IEEE802.15.4e-2012 (p 59) >>>> indicates it is composed of the following field. In *blue* example >>>> values for an unencrypted ACK frame. >>>> >>>> - [bit 0-2] Frame Type *(value for unencrypted ACK: 0b010==2==ACK)* >>>> - [bit 3] Security Enabled *(value for unencrypted ACK: 0b0)* >>>> - [bit 4] Frame Pending *(value for unencrypted ACK: 0b0)* >>>> - [bit 5] ACK request *(value for unencrypted ACK: 0b0)* >>>> - [bit 6] PAN ID compression *(value for unencrypted ACK: 0b1)* >>>> - [bit 7] reserved *(value for unencrypted ACK: 0b0)* >>>> - [bit 8] Sequence Number Suppression *(value for unencrypted >>>> ACK: 0b0)* >>>> - [bit 9] IE list present *(value for unencrypted ACK: 0b1)* >>>> - [bits 10-11] Dest. Address Mode *(value for unencrypted >>>> ACK: 0b11==3==64-bit)* >>>> - [bits 12-13] Frame Version *(value for unencrypted ACK: 0b10==2)* >>>> - [bits 14-15] Source Address Mode *(value for unencrypted >>>> ACK: 0b11==3==64-bit)* >>>> >>>> These fields are organized in the following 2-byte "structure": >>>> >>>> xxxx xxxx xxxx xxxx >>>> 010 = Frame Type (3 bits, value 0b010) >>>> 0 = Security Enabled (1 bit, value 0b0) >>>> 0 = Frame Pending (1 bit, value 0b0) >>>> 0 = ACK request (1 bit, value 0b0) >>>> 1 = PAN ID compression (1 bit, value 0b1) >>>> 0 = reserved (1 bit, value 0b0) >>>> 0 = Sequence Number Suppression (1 bit, value 0b0) >>>> 1 = IE list present (1 bit, value 0b1) >>>> 11 = Dest. Address Mode` (2 bits, value 0b11) >>>> 10 = Frame Version (2 bits, value 0b10) >>>> 11 = Source Address Mode (2 bits, value 0b11) >>>> ------------------- >>>> 1110 1110 0100 0010 = 0xee42 >>>> >>>> Because this 2-byte field is sent "little endian", what you will see in >>>> the air is 0x42ee. >>>> >>>> >>>> >>>> *Example 2*. header of a "ACK/NACK Time-Correction" IE >>>> >>>> Format of a header IE (IEEE802.15.4-2012, p.57) is below. In *blue* example >>>> values for a "ACK/NACK Time-Correction" IE. >>>> >>>> >>>> - [bits 0-6] Length *(value for "ACK/NACK Time-Correction" IE: 2)* >>>> - [bits 7-14] Element ID *(value for "ACK/NACK Time-Correction" IE: >>>> 0x1e, see IEEE802.15.4-2012, Table 4b, p.81)* >>>> - [bit 15] type *(value for "ACK/NACK Time-Correction" IE: 0, as >>>> it's a header IE)* >>>> >>>> These fields are organized in the following 2-byte "structure": >>>> >>>> xxxx xxxx xxxx xxxx >>>> 000 0010 = Length (7 bits, value 2) >>>> 000 1111 0 = Element ID (8 bits, value 0x1e) >>>> 0 = Type (1 bit, value 0) >>>> ------------------- >>>> 0000 1111 0000 0010 = 0x0f02 >>>> >>>> Because this 2-byte field is sent "little endian", what you will see in >>>> the air is 0x020f. >>>> >>>> >>>> On Wed, Jun 24, 2015 at 11:12 PM, Tom Phinney <[email protected] >>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: >>>> >>>>> Agreed. We've struggled with this Endianness issue since the early >>>>> days of Ethernet and IEEE 802. Blame it on HDLC. >>>>> >>>>> To eliminate the ambiguities, always list the bytes in transmission >>>>> order, together with a prominent note that >>>>> a) the bytes are listed in transmission order, and >>>>> b) each bytes is transmitted lsb first. >>>>> >>>>> -Tom >>>>> ==== >>>>> >>>>> On Wed, Jun 24, 2015 at 9:54 PM, Simon Duquennoy wrote: >>>>> >>>>> Hello, >>>>>> >>>>>> I believe what we want is the frame content as a series of bytes (not >>>>>> bits, >>>>>> symbols or 16-bit words) in the order in which they are sent and >>>>>> received. >>>>>> Here the second byte, in binary form starting with least significant >>>>>> bit, >>>>>> is: 11111100 (as mentioned in your mail). That's unambiguously 0x3f >>>>>> (== >>>>>> 0b00111111, == 63). >>>>>> >>>>>> Best regards, >>>>>> Simon >>>>>> >>>>>> >>>>>> On Wed, Jun 24, 2015 at 5:55 PM, Xavier Vilajosana < >>>>>> [email protected] >>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> >>>>>> wrote: >>>>>> >>>>>> Sorry option 2 was incorrect.. too fast copy&paste >>>>>>> >>>>>>> 2) Another option is to convert to hex by considering the MSb first >>>>>>> within >>>>>>> the octet >>>>>>> MSb LSb >>>>>>> 0000 0000 1111 1100 >>>>>>> 0x0 0x0 0xF 0xC >>>>>>> >>>>>>> 0x00 0xFC >>>>>>> >>>>>>> regards, >>>>>>> X >>>>>>> >>>>>>> 2015-06-24 17:53 GMT+02:00 Xavier Vilajosana < >>>>>>> [email protected] >>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>>: >>>>>>> >>>>>>> Hi Tengfei, >>>>>>>> this is confusing. Lets make sure this is the right way. >>>>>>>> >>>>>>>> For me the problem is how do we transform an HEX WORD to 16bits >>>>>>>> >>>>>>>> for example can be interpreted from left to right as LSB and from >>>>>>>> MSB >>>>>>>> being right to left when transforming the binary representation to >>>>>>>> the Hex >>>>>>>> representation >>>>>>>> >>>>>>>> Taking this IE as example >>>>>>>> >>>>>>>> 1) Header IE: list termination: >>>>>>>> len = 0 as bits 0-6 >>>>>>>> id = 0x7e as bits 7-14 >>>>>>>> type = 0 as bit 15 >>>>>>>> header = len + id << 7 which gives 0x3f00 >>>>>>>> >>>>>>>> if we consider that E in 0x7E is the least significative 4bits and >>>>>>>> least >>>>>>>> significative bits are placed first (most left) we have: >>>>>>>> >>>>>>>> 7 zeros 0x7e type 0 >>>>>>>> 0000000011111100 >>>>>>>> >>>>>>>> 1) When transforming this to HEX we consider the least >>>>>>>> significative bits to >>>>>>>> go first from left to right. So >>>>>>>> LSb MSb >>>>>>>> 0000 0000 1111 1100 >>>>>>>> 0x0 0x0 0xF 0x3 >>>>>>>> >>>>>>>> 0x00 0x3F >>>>>>>> >>>>>>>> 2) Another option is to convert to hex by considering the MSb first >>>>>>>> within the octet >>>>>>>> MSb LSb >>>>>>>> 0000 0000 1111 1100 >>>>>>>> 0x0 0x0 0xF 0x3 >>>>>>>> >>>>>>>> 0x00 0xFC >>>>>>>> >>>>>>>> >>>>>>>> What is the right option? I am not sure but seems more reasonable >>>>>>>> to be 1) >>>>>>>> >>>>>>>> Maybe those annexes in 15.4 can help to find the right answer. >>>>>>>> >>>>>>>> regards, >>>>>>>> Xavi >>>>>>>> >>>>>>>> >>>>>>>> 2015-06-23 17:33 GMT+02:00 Tengfei Chang <[email protected] >>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>>: >>>>>>>> >>>>>>>> Jonathan , >>>>>>>>> >>>>>>>>> Could you pointed which annexes or a page I can refer to? Did it >>>>>>>>> say >>>>>>>>> that is an example that transmitted by PHY? >>>>>>>>> >>>>>>>>> Tengfei >>>>>>>>> >>>>>>>>> On Tue, Jun 23, 2015 at 11:27 PM, Jonathan Hui < >>>>>>>>> [email protected] >>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> As mentioned in my previous mail, the annexes in the IEEE 802.15.4 >>>>>>>>>> specification use the convention I outlined. >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Jonathan Hui >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Tue, Jun 23, 2015 at 8:21 AM, Tengfei Chang < >>>>>>>>>> [email protected] >>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>>>>> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> The hex value is correct. But I don't think this is the way to we >>>>>>>>>>> should follow to order the data. IEEE802.15.4 said we should >>>>>>>>>>> transmit the >>>>>>>>>>> first bit, so we should follow this order. >>>>>>>>>>> >>>>>>>>>>> Tengfei >>>>>>>>>>> >>>>>>>>>>> On Tue, Jun 23, 2015 at 10:56 PM, Jonathan Hui < >>>>>>>>>>> [email protected] >>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>> Tengfei, >>>>>>>>>>>> >>>>>>>>>>>> Hex values are typically written in MSB order - this is >>>>>>>>>>>> different >>>>>>>>>>>> from IEEE 802.15.4 which writes bit strings out in LSB order. >>>>>>>>>>>> >>>>>>>>>>>> For example: >>>>>>>>>>>> IEEE 802.15.4: 10000000 >>>>>>>>>>>> is equivalent to >>>>>>>>>>>> Hex: 0x01 >>>>>>>>>>>> >>>>>>>>>>>> So, w.r.t. the bytes being discussed: >>>>>>>>>>>> IEEE 802.15.4: 00000000 11111100 >>>>>>>>>>>> is equivalent to >>>>>>>>>>>> Hex: 0x00 0x3f >>>>>>>>>>>> >>>>>>>>>>>> See the Annexes in IEEE 802.15.4 to see many more examples of >>>>>>>>>>>> hex >>>>>>>>>>>> representations of MAC frames. >>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> Jonathan Hui >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> On Tue, Jun 23, 2015 at 7:39 AM, Tengfei Chang < >>>>>>>>>>>> [email protected] >>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>> I don't think 0x00 0x3F is right. >>>>>>>>>>>>> >>>>>>>>>>>>> In section 5.2 of IEEE802.15.4 standard, the second paragraph >>>>>>>>>>>>> said : >>>>>>>>>>>>> >>>>>>>>>>>>> The frames in the MAC sublayer are described as a sequence of >>>>>>>>>>>>> fields >>>>>>>>>>>>> in a specific order. All frame formats >>>>>>>>>>>>> in this subclause are depicted in the order in which they are >>>>>>>>>>>>> transmitted by the PHY, from left to right, where >>>>>>>>>>>>> the leftmost bit is transmitted first in time. Bits within each >>>>>>>>>>>>> field are numbered from 0 (leftmost and least >>>>>>>>>>>>> significant) to k – 1 (rightmost and most significant), where >>>>>>>>>>>>> the >>>>>>>>>>>>> length of the field is k bits. Fields that are >>>>>>>>>>>>> longer than a single octet are sent to the PHY in the order >>>>>>>>>>>>> from the >>>>>>>>>>>>> octet containing the lowest numbered bits >>>>>>>>>>>>> to the octet containing the highest numbered bits. >>>>>>>>>>>>> >>>>>>>>>>>>> When transmitting the data, we should make sure b0 goest first. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> *For termination header IE * >>>>>>>>>>>>> *1) Header IE: list termination:* >>>>>>>>>>>>> *len = 0 as bits 0-6* >>>>>>>>>>>>> *id = 0x7e as bits 7-14* >>>>>>>>>>>>> *type = 0 as bit 15* >>>>>>>>>>>>> *header = len + id << 7 which gives 0x3f00* >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> When transmitting the 00 3F, the bit transmitted by PHT is bit >>>>>>>>>>>>> 7, >>>>>>>>>>>>> not b0. >>>>>>>>>>>>> >>>>>>>>>>>>> => in the document, it is currently 00 FC: 0000000 01111110 0, >>>>>>>>>>>>> >>>>>>>>>>>>> The first 7 bits goes is len field bit0-bit6: 0000000, then >>>>>>>>>>>>> goes >>>>>>>>>>>>> ID: b7-b14 7E 01111110, then type bit 15 0. >>>>>>>>>>>>> >>>>>>>>>>>>> Which is Correct. >>>>>>>>>>>>> >>>>>>>>>>>>> Tengfei >>>>>>>>>>>>> >>>>>>>>>>>>> On Tue, Jun 23, 2015 at 12:14 AM, Xavier Vilajosana < >>>>>>>>>>>>> [email protected] >>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> Dear Simon, >>>>>>>>>>>>>> >>>>>>>>>>>>>> thanks for your comments. I might have messed bits up with >>>>>>>>>>>>>> endianness. I will recheck again. Note that we read them from >>>>>>>>>>>>>> left to right >>>>>>>>>>>>>> being the leftmost the least significative bit and the right >>>>>>>>>>>>>> most the most >>>>>>>>>>>>>> significative bit. >>>>>>>>>>>>>> >>>>>>>>>>>>>> in this case and taking the first element you mention >>>>>>>>>>>>>> >>>>>>>>>>>>>> 7 zeros 0x7e type 0 >>>>>>>>>>>>>> 0000000011111100 >>>>>>>>>>>>>> >>>>>>>>>>>>>> if I convert this to hex where the least significant bit is >>>>>>>>>>>>>> the >>>>>>>>>>>>>> leftmost it leads to >>>>>>>>>>>>>> 0x00 0x3F >>>>>>>>>>>>>> >>>>>>>>>>>>>> as you indicate. >>>>>>>>>>>>>> >>>>>>>>>>>>>> thanks so much for your comment! >>>>>>>>>>>>>> X >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> 2015-06-22 17:48 GMT+02:00 Jonathan Hui <[email protected] >>>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');>>: >>>>>>>>>>>>>> >>>>>>>>>>>>>> As someone who has implemented and deployed product that use >>>>>>>>>>>>>>> IEEE >>>>>>>>>>>>>>> 802.15.4e-2012 Information Elements, I agree with Simon's >>>>>>>>>>>>>>> encodings. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>> Jonathan Hui >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, Jun 22, 2015 at 4:21 AM, Simon Duquennoy < >>>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Dear all, >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I believe the example IE headers (for header/payload/MLME >>>>>>>>>>>>>>>> IEs) >>>>>>>>>>>>>>>> are wrong in section 10.1 of the minimal draft. Some >>>>>>>>>>>>>>>> endianness confusion I >>>>>>>>>>>>>>>> guess: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> 1) Header IE: list termination: >>>>>>>>>>>>>>>> len = 0 as bits 0-6 >>>>>>>>>>>>>>>> id = 0x7e as bits 7-14 >>>>>>>>>>>>>>>> type = 0 as bit 15 >>>>>>>>>>>>>>>> header = len + id << 7 which gives 0x3f00 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> => with little endian encoding we get: 00 3F >>>>>>>>>>>>>>>> => in the document, it is currently 00 FC >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> 2) Payload IE Header (MLME): 1A 88 seems correct >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> 3) MLME-SubIE TSCH Synchronization: >>>>>>>>>>>>>>>> len = 6 as bits 0-7 >>>>>>>>>>>>>>>> id = 0x1a as bits 8-14 >>>>>>>>>>>>>>>> type = 0 as bit 15 >>>>>>>>>>>>>>>> header = len + id << 8 which gives 0x1a06 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> => with little endian encoding we get: 06 1A >>>>>>>>>>>>>>>> => in the document, it is currently 06 34 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> 4) MLME-SubIE TSCH Timeslot: >>>>>>>>>>>>>>>> len = 1 as bits 0-7 >>>>>>>>>>>>>>>> id = 0x1c as bits 8-14 >>>>>>>>>>>>>>>> type = 0 as bit 15 >>>>>>>>>>>>>>>> header = len + id << 8 which gives 0x1c01 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> => with little endian encoding we get: 01 1C >>>>>>>>>>>>>>>> => in the document, it is currently 01 38 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> and so on.. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> My apologies if it is me misreading something. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> One other minor remark: in section 10, when describing byte >>>>>>>>>>>>>>>> order, I would suggest referring to "little-endian >>>>>>>>>>>>>>>> ordering" rather than >>>>>>>>>>>>>>>> "LSB format". >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>> Simon >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>> 6tisch mailing list >>>>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/6tisch >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> 6tisch mailing list >>>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/6tisch >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> 6tisch mailing list >>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/6tisch >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> ------------------------------ >>>>>> >>>>>> _______________________________________________ >>>>>> 6tisch mailing list >>>>>> [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>> https://www.ietf.org/mailman/listinfo/6tisch >>>>>> >>>>> >>>>> _______________________________________________ >>>>> 6tisch mailing list >>>>> [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>> https://www.ietf.org/mailman/listinfo/6tisch >>>>> >>>> >>>> >>>> _______________________________________________ >>>> 6tisch mailing list >>>> [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>> https://www.ietf.org/mailman/listinfo/6tisch >>>> >>>> >>> >> >> _______________________________________________ >> 6tisch mailing list >> [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> >> https://www.ietf.org/mailman/listinfo/6tisch >> >> >
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