一分鐘讀懂低功耗藍(lán)牙MTU交換數(shù)據(jù)包

一分鐘讀懂低功耗藍(lán)牙（BLE）MTU交換數(shù)據(jù)包1.概述MTU:最大傳輸單元（MAXIMUMTRANSMISSIONUNIT）,指在一個PDU（ProtocolDataUnit：協(xié)議數(shù)據(jù)單元，在一個傳輸單元中的有效傳輸數(shù)據(jù)）能夠傳輸?shù)淖畲髷?shù)據(jù)量（多少字節(jié)可以一次性傳輸?shù)綄Ψ剑TU交換是為了在主從雙方設(shè)置一個PDU中最大能夠交換的數(shù)據(jù)量，通過MTU的交換和雙方確認(rèn)（注意這個MTU是不可以協(xié)商的，只是通知對方，雙方在知道對方的極限后會選擇一個較小的值作為以后的MTU，比如說，主設(shè)備發(fā)出一個150個字節(jié)的MTU請求，但是從設(shè)備回應(yīng)MTU是23字節(jié)，那么今后雙方要以較小的值23字節(jié)作為以后的MTU），主從雙方約定每次在做數(shù)據(jù)傳輸時不超過這個最大數(shù)據(jù)單元MTU交換通常發(fā)生在主從雙方建立連接關(guān)系后（參見”一分鐘讀懂低功耗藍(lán)牙連接數(shù)據(jù)包”）做個對比就可以知道BLEMTU比較?。ú贿^新的BLE標(biāo)準(zhǔn)MTU已經(jīng)大幅提升，詳見即將發(fā)表在VIEWTOOLBBS上的后續(xù)文章）。****************************************************************“******以太網(wǎng)：1500IEEE802.3/802.2:1492X.25:576BLE:23=＞這就是為什么WIFI可以用于傳輸視頻，傳統(tǒng)藍(lán)牙（BT）可以傳輸音頻，而低功耗藍(lán)牙（BTLE或者BLE）只能夠傳輸控制數(shù)據(jù)的原因了。MTU交換命令：屬于ATT命令MTU交換過程：如下圖

柚湖UtqProtocol停丁D@BluetoothFrgufe3.1:MTUrequestandresponseexchange②③⑤MTU=100MTU^IOO*MTU兩個命令（“MTU請求"及“MTU響應(yīng)〃）詳解如下（見、'4〃）關(guān)鍵字：Hollong柚湖UtqProtocol停丁D@BluetoothFrgufe3.1:MTUrequestandresponseexchange②③⑤MTU=100MTU^IOO*MTU兩個命令（“MTU請求"及“MTU響應(yīng)〃）詳解如下（見、'4〃）*硬件：一個BLE設(shè)備（從設(shè)備）及對應(yīng)的主設(shè)備（如智能手機(jī)里面的相關(guān)應(yīng)用程序，或者通用BLE工具軟件）；一臺HOLLONGBLESNIFFER（HollongBLE偵聽儀）*軟件：Hollong藍(lán)牙4.0/4.1BLE協(xié)議監(jiān)控分析儀軟件，使用本軟件可以打開本文中的數(shù)據(jù)包附件，進(jìn)而可以更加方便及更加全面地了解更多細(xì)節(jié)（包括最全面的數(shù)據(jù)及數(shù)據(jù)解析）下載鏈接：/index.ph...hollong-4-0-4-1-bleMTU請求（REQEUST）完整數(shù)據(jù)（以下關(guān)注藍(lán)色標(biāo)注部分）ri?a*亡41丹5￡|亶二亙爆鼠映1?UJl—radH1EW*MiTimffwiM-hnmn<?JrinxiJIxkpJ*.En￡>.l#.白，131瞄uNaiDhr_flauii*9jlc49unlnotrjiauri*9j1c49Ji.1TLE-■-HcmTUdriiiEtacnE^achiir^i-KillHc^hst,GLhveRinil:U%□*PU￡?4i￡iWxi*色時心g血更g毋通IMiIH涵1-3K3^14W■'■*■TbnJCfiu冊M.gF&i虹#untMM』俱ftjugE,,i—a碩\TTIE-iJNcryMfl3M<T5MEXhi^dtH7UR?5jH^FKj8卅卜HTU!21?—jTkdn一4iTT凸-J「■TTFrjwftBi:Jtbycv.onvirtpZIEn],3Abycvw-uptmd(131Rti■卜oninnrtjcr■?ELu跑om|SEvrc?:urfc-iown■■^lurt-zpthLc+r■■^lurt-zpthLc+rEntrfji'LinkLayarAccessiMJysj：Ihnl:■-處d—:1k(4^.K.bd-73■:JB:hE)J[■5]^Hg5：時璃W"MWI]*H4心r:SsBW4H._...-KFU:□…日.■■.Har>a[gu!^?15K-....&.._?￡rlE^HFK?Hiabcr:$!■■-*feKtLHMCTePS收土1...-..1$，LLU=StdrtpfanL2L#a?m^4nrjLlO^hsme^withmfrdmintdtain[fedOflW--..--RFU?R...BEH■Lvngth:?-Er；[Liptiril^o「缸illenav-alhtk-]+IQurfcscithL2CEFPnaTdeoLL4r^h33LCD:^ttrahjtnh-wacoJ|■*JluiswoThPe&mI■Llpcmi!：EachainKHTU際年h*M航Ifg…rIar■也】he<Tt]citLixiSLimeit;f-slw.6.._...■:FmLiv..4t40L?■SI*Cli^a心XTIjs域1）存取地址AccessAddress:0xaf9a8c69固定為4個字節(jié)，其值由連接請求數(shù)據(jù)包指定（詳見''一分鐘讀懂低功耗藍(lán)牙連接數(shù)據(jù)包〃）■■i：lurtctfcKL?iEntrfyLintLayar■EEUM.rqLf■■i：lurtctfcKL?iEntrfyLintLayar■EEUM.rqLf吏皿?4Ei嶂BmMl^*EJg也M-15Jg主inm■KiHjrik0-r*音4*IE7iS=威曲WI?IPU>IL囹q4蜀財(cái)役MiTimf<WH-hniMii-HjTMWiJIxkf'hEn￡^，Lh.Mlil瞄uNorDhr.j9立i*個■c4#urJ7iCH"u_aauii*9jlc4&ilTLE-iJ^rATUdmctacnE^chw^i-PHURd^Mst,ClL?ntKtWU:LI%i3所的」的wseUMSM.gF逮函ATTIBLHcEMfllFflCdEE>ChS^atMUWkHTlh：23-A—h-?—...Ig-xnq—i：n■TTa_.b■Cl.fT-一_ft■_fATTdl<1-一h—_T__J—u—^*1__.O-MAnHzluMgr*€Ct5iMJySi|itir-U:ic:bd:7L20:tK(4^1.k.bd.71:J&:bcHhimtHreise^LcwjM：W?<flc;iF3；M-W^MWI]旨陌TdiM^hr:6stWtm.....■rfu：a…日.■■■p&E[LJD3!&315PU?JcrMnc。敢....?1>.-HeKtbpecTCPSe^-^nce1.......1$國LL]Q=SUirirfmL2L#>?砒#arj&waMEdwithm-firi^pintdtajnm.-...-RFUsR...B4H1■-Lvnfkh:?-Er；的e晚[Fjip?^iInfo。缸wia11oaiaav-aikbLe-]■rSdurfcacrthL3CEFFnaTOCDLurgchi3L[L>:Athrab'jtHIV^tacoJ{>^41664|■*Slueraoihp^kqI■Llpca?:EuhEjinrfllj也MH：'4-.；Fl..-iilhcntR-lTLcn5L|Mrurr-；Ffllw.6.._...■FmLiv..4fr4DL0■Nc-zhiZid:Eiichitr^i-MTU-JduailCJl^-n:4MTUi19(lBg<anrminFr—?:PtMIIWU)EfltCTMW祖州02MOfl仰財(cái)邪.、，??，“：，尊#riKMEbd^-iRnnu-4卓節(jié)|或蛆3WeJET-瀏D做"QKI14ID13)FM廈￥FC!li2)頭信息DataHeader:0x0706000.....=RFU:0...0....=MoreData:False

....0...=SequenceNumber:01..=NextExpectedSequenceNumber:110=LLID:StartofanL2CAPmessageoracompleteL2CAPmessagewithnofragmentation(0x2)000.....=RFU:0...00111=Length:7J"?ti-SM>l-5mi-^OtHjJIpopng?LCil_Ncni>r^]recT5vi*TUne#*/”ClientHiPH1.1■|J?iJv*:ruwfAir4￡T]mhTU陌苫網(wǎng)?。ポS2+際HTU.21*f4iB44西WLXiMe^*曲LCil_Ncni>r^]recT5vi*TUne#*/”ClientHiPH1.1■|J?iJv*:ruwfAir4￡T]mhTU陌苫網(wǎng)?。ポS2+際HTU.21lit.awgrw注W為鼻gUi■煩眥n』頑知"pATTui^W8■■白心網(wǎng)淑舌，u而蹄\_白俱白輸砧ATTmaw網(wǎng)船36byrij-smFy1.138c-spti^edC12Re口Bljurtccrth|$WJ「憤?di*jEWd「知SoMJ|DnkJn?t3Dn:ur*rwwr-_flMf?Lr*>EniH-gyLint岫網(wǎng)區(qū)：[的|HoH±kOddwi--li.：HT：bdr71-J9:t?(Uricbd:?!■:26:bc|:SUe城IP4WMLcrtitjW：WW<4ci^iH慎感慎HfUitjHciuhir:DaSHL?■RFU:e.■■Mar*[LiEm?b1ik4i.c-0.1..?Nextbepact*idS?q.ofiEa1■、說-LLU>sScaunLM**?-acQwlrteL2C乎>K9f4^wLth<w丑I.M]dM-AFu：fl■..?4UJ-Li^Cthi7[E-?wn:lirro做wrhetKyi;g*物b碩41]頗占wiubLel機(jī)umwmLKAFFwiofitiLLength:'3CID:如CEbuWFtoimqJ?*[SJxiBTscrthATtrdbunPrirtEca]激O0C494!EUhMfliiHTU問翊XT(,4m?■2..._..-■■AjT^HrrEd^iTLcnHi..ii.■CCRWhdFaLS4_.4fi-H■廿C】150MHJ!瑜3)L2CAP長度在BLE中，GARGATTSMP都使用L2CAP通道將命令及數(shù)據(jù)打包送到鏈路層(LINKLAYER),L2CAP打包過程中需要指定L2CAP的長度及通道號。Length:3MiTimffVM-hnirwii-?NtixTbn<*hEr3，l"lidEJintEuNaiCH-!_flxjif&jlc4&urikncH-i_fliuf^jlc4SAITLti-ktcrwildnctamE'lEhAr^*K1UHci^Hit,,ClLhytfiiKill:U%19KMS914Mu版ur*"Mj?*&rfcS9AH:L&grw偵mmcdOHEiHiMflG*H1U雨*?小碼BkHOJ;3直日g_5一“I—,__O—■XYig—L*…——_g—__?TT*■」_—_JT—_A——J_1_—aa—a—h,—W*^ri*Frjw做I:3i5byfcvaonhrira|J7JmTEj,byfcviiciiptmd(UEsdti.}mlunrfjcpB=Slurainh|3nim:ji4c.-!OtaTi_4Kiftz-S-9)|[R^C1>1K5#I；un|4ft5*rr._Qwif9aM9]■"iMbjwtgthLe+tEn?r^()fLinkLwyir*cceisHMyii：H頑朝|妍Ihat■-Add—m.*:?“bd:.為匚網(wǎng)：t?(44.g-bd“囂:上日:昨*][51m1：*認(rèn)2：_網(wǎng)：炯睫Hn；r5：ttTOWMI|』皿日&做栓土B?版?h.....?kfu：□...B.I.B?Hag財(cái)CTfSilSE-..-4..-■￡r?qMrKi-niabsr:>3■■■>■!■■-HfinE^peciepSetMnceHuM>eri1-.1^■LLU=StdrtpftnL2L#ar?s-s^aJntvL^CAPmku|>ivLthm￡ftc2)m--...-wu?H-..mi?L-iryth:?-Er；的口十5伸3[Fjtp?n:Info(Hac^i'CmcK^m)!〔就miom^jkbl?]+BJurtccrthL3UFPtstocdL■-4f<Ch!3LCD:Mterabutaf￥?1?caj■*Slyraoih具rrrlbi/ttPfiytKal"OpcDCfl：EichanjvFfTU44xdl>L、r?...■⑶T#w*Tt!kdi：LgSUMiug;F-alw-6......■■(砒imM:FtiLar..AtSDL?■Me-shad:EiEhdn^i-MTU溶由玲ai^?J<rui誕I'F^rcn*11I-tjw-:TO!Imd的r火m誠市WEsi?r?ra"wimttja#3b—lTTT.Ha.5-nrr+Heiwhm□ikin.fianiELt'-HcrwifldmctaEnEFEhar^i*KillC]L?fYtRiKill:U%—9t829firiri■-■*■TinJiCfiLtLWc^>fffl3r4?：T：5M白thMflifcHIU府泌小丸AkHTU]23.一—_JT—_A——JZA1T_\，StMirfiJbn<>hEn￡>4)L2CAP通道號(5-nrr+Heiwhm□ikin.fianiELt'-HcrwifldmctaEnEFEhar^i*KillC]L?fYtRiKill:U%—9t829firiri■-■*■TinJiCfiLtLWc^>fffl3r4?：T：5M白thMflifcHIU府泌小丸AkHTU]23.一—_JT—_A——JZA1T_\，StMirfiJbn<>hEn￡>Ffjw制，：3i5br^tvaontriiM[1ZI日打叩』2SbyeveciptLT-id(]]E時ehjjitarfjcr&jSlufrTaOTft|3cum:jr^c.-!cwri4hcifP?E!：M』lEk^clnHSM；unfe*wri_flMfEiaM9]■"度Lj?tu<fthLc*iEnar-f$fLinkLar^ar*c?M5iyjj；IhnkHTAdd^aij44:■E^bdzZ^Jri:be(44^iKxhi^73-:Jb:bE.3>][51mMJ吒i：-*<LcrQr-_W：ffiMW^W：WI)』心口土B7鑫4H._...?KFU:□...P.ii.■HflM[mQ!^?15EU.._P￡r*qMFK?nLH^?r：$.■■■?!■■-*皿￡4KtTCP5eq>x*iseftWwci1...-..16■LLU:StdirtpftnL2￡jVarjic-s^aJakiiwhui^wLthra"Frvwntdtim[fec2)#W-....-RFU；e_..B41tl-5用的：?-Er；-[Fj?p?n:Info(HaE?i*￡r>bCK￡irt')!「就由』Allmc^MlLabL?]?*[BJurfc^crthL7CAFPr^TMtiLUngth!JLCL):AttraiMtaiVSaru]仲痂iM|■*?l?ra^Th具wlbiXttP^K'll■OpcDM；EichanirMTU砒M涌】;j4：■r..r■國nheflticiTLMSLijme*;R]?-日…_...■C^HMnd:FttLav..dfr?DL??&■:hod:Ei￡hrir^?MTUHiflt>??Eiflxfll}◎Imht-KTUi185-|[卜。=<7〕1，lr「!■■!?■：7K?I5)ATT命令標(biāo)準(zhǔn)發(fā)下：

3.4.2MTUExchange34.2」Exchafi"。MTUReau淑TheExchangeMTURequestisusedbytheclienttoinformtheserveroftheclientsmaximumreceiveMTUsizeandrequesttheservertorespondwithitsmaximumreceiveL1TUsize.ParameterSize(octets)DescriptionAttributeOpcode10x02=ExchangeMTURequestClientRxMTU2ClientreceiveMTUsizeTabl^3.4:FormstofE對旭。薩MTUR&qu&stTheClientRxMTUshallbegreaterthanorequaltothedefaultATT_MTU,Thisrequestshallonlybesentonceduringaconnectionbytheclient.TheClientRxMTUparametershallbesettathemascimumsizeoftheLdributPproto*colPDUthattheclientcanreceive.UIUSUURCOOI實(shí)際數(shù)據(jù)包：Opcode:ExchangeMTURequest(0x02)0=AuthenticationSignature:False.0=Command:False..000010=Method:ExchangeMTURequest(0x02)6)MTU值(請求的值)ClientRxMTU:185*Iimfn-N-hnir?ii-?JtinwdIxkf'hl2-3.63]31EurJoiCM-.jaufilITIE-'JNcrwildractaDnEschar^i-IV1UCILhyeRsnil:LI%-■3K23.&314WuntoflfiBFi^iMlf&iScSP」冊由.厚中&#&69AH場gEMfllNCTiBI自的迥女HIUKiSjM我I；殆父W"HIMMf，A4"?"，MMn*■-?Ln■■MIM■nMH-mLnAI—_劣■■MiMCl—M-mI—訪一—M■W^aJ(JI—_?_FtjwUS，：JHb^rvaan5e[1ZIHEii',1Ht^rwiiciiptu-^d(UEbdti■卜miJirarfjcvBw51UST00TH|ji4c.-iawri_4Kif9jF-:-!-!?*||氐#MmiMSMr^c*rn_3M|f&aM5]■■Lslurtc-o-thLdkEnar.yLinkLwyirAccesstMrejj：肛引由^由|h?t■-Addr^ifi..4^-:ic.bd.7)jj]:be(4*4.rc.hd.72-:2B:bcH[31mMtJre?：El匚sjfi：饕M?c;?3：w?*lMMI|盼0脂皿廣：6sBW4M■KFU:□...P.i>.?MagQju!^?lsis-q?!>?CTMrK?Hiflt?ir:肉....?1>.-HektEmKtlevSeqwMit版址叫1....-.1^■LL10=StdripftnLJ[耕ar溜c-s^iJiitrL^CR^waiii^uLthm-Fr<jivnl:?i:im[^2J....-RFUBP-..i&am-bir^fch:7-E〔；隊(duì)"5的[E'pamInfo葫fmrKTWhiMijAlltuti村Flabbfr：■?I^lurfcacrthL3UFFnaTOcaLi4rtfth!JLEU:Attrahjtah-^tacaj|#0-luMQOThArtr-lbirteP^OTKalaLIpcDC^i:Eichar^ivrilllR?i^M>t4!!-!11r業(yè)ihffElGITLBiSlfMrurt-；FflJ-je.6，C：a?M'nd:FaLav..4frSDL?-N?3hcd:■-MTUHdEpME'flxfll}口Mt4mi1^5-I，mniwlil~ra?^:牌■IMD的&馳ffltCTMWAl贛藏皿言而在邪―L..；■.a.7)CRCMl1IMfn*N-hniMII-MJTMWiJIxkf'hEn￡?-^KQ2-a.aS]31EunioicH-.jaiuMmEPurJoicwijaufW?EPilITLt'JrtcrwildraEtaEnEschar^i-imuHai^Mst^CILhyeRinil:LI%?m23.ISUWu?*)flgr漁iMF&iScSMuNonm.HW&i&SWATJLBUn*cno*ffl3PflCT5M&CharafcWIURiSjXl^Fitj54*^4^a?HIV!2J_n，■、w__.—j■*.n?n_a■■mim■.nmh-mlVi—nbitt心iLax?hh——劣■■ei—■-?!th■1wm<r■—.占—l1artlm，二——f&m—.?,.土』1——■￡l^eh.FtjhbUS，：JHb^rvaar?i5e[1刃Ii9tejjJH呼Bnciiptir^d(UEbdtij-cnInnrfjcvBeiumg|SEvrc?:ui4c.-!awn_Acif9jE^s59)I氐#MHiMiur^wn_flM|f&aMS]■?[Jlurtcc-tfLdhEnar.yLinkLwyirX?m-it-Mress：|hnt■-Addr?3ih.4<-:ic.bd.7).2(!:bc(4^.r-z,:bdj72-:2B:bc，H[51mk?re山：&*<Li：rQr-_iM：lwH4flc;iF5：wW：MWl|陌1im6sBW?M._...?kfu：□.1.."由、gD3!^SlSiS-a。Jwwkwn?w>r：散....?1>.-HckiE^petiepSequenceWuMw^i1......1^?LL]O=St^ripfmLJ￡#MAhri^flarjwJuti1mbmebuLthm1-dcjivntriituvi[^2)W-....-KFUlP...?am■-L<nath：j?*E「；Hg岫[F'pAMInfO(HO[?i*￡fM￡KtilA)!葫furKT^hiM,MlMtiSvFlibLm：■■SJjurHDrthL3C￡FFnaTacaLL4rtf1：h!JLEO:Atkrahjtnh-^taenj1j*S-luMQOTt-iAttr-lbirteP*--OTK?]1aLIpcDC^i：Eichar^irHR]R?i^M>t4.!.R|..■iiljientlcitlwSLfMturr-；Ffllw.6.-_...■〔《??出：FaLav..4frSDL?-Haihad:Eichu^a-HTU[口心CJl^t也JfTUl18(lRM.smiiRiiPraaw■:WjfImd訶"ST虱時?ermwa*w?zmw1ZZ3E1-......r....QOCl￡0.-0+ori]..3E4.MTU響應(yīng)（RESPONSE）完整數(shù)據(jù)包：

■-一■―=*fUE-44i￡i例毗曲曲g也MniIT?FIBillfBijfl■重二巨或或2H口UalL(3L]A1EW*Timhnirwn<?JrbiKiJIxfarJ,![rvt>*lTa.dlUriEUSE白■jrJ-TitM~i白隊(duì)fP>alr4PillTLE-'-HcroiTCdnffctacnE~ichAF^i-H1Unfl^Hii.t(ClL?rrtRsK1U:U%U--3的？3.部14的U冊曰AITItH7VR4-HHfVEKj外卜日黃MTU.叫..Th-——..盤癡——土-^-rd?tt—i~ui__-■■■0—i尹-■-r.__卜r*E■*-]=-FtjwMK:]&ir^Eiraontrim1321b^TEjjISkr^cvn^aptrnd(13EEt罰cndJinrfjcrjeiuiraml^nim:jntcrcvnIDWClnMiM：■[=：lu?t-=pthLhi*EnwiJi'Link:Lari>ar|Knk■-44:?EbdTL^:氐[4.z.bd:四:部:虹門Sua岫0+Eig七明睥輯(fluC；WW-WWlj*Cm口土中[上.-kfu：n??HariEmu!Tm-...U.._?J/HFK*Rl■虹r=$土-HeKt巳世1kpSeqx*i!：eHuMw^-iB16，LL10:St?rtpf?iLJC#H3ihd￡4araw?pl砒■■L±O^msmeiwithm*FifBTiMkun[frc2J#W-....-RFUlR...H41tl?■Length:?-Ef；Rgmlnfi>(HaE^.i'CrNCK^iri'):￡fl￡uftc^e^Wjstillnn^Ikbbfi-]?*[BlurcstrrhL2UFPncT?nLL4Hgrh!JLED:MtraixitBh^tacnjSkMIMM|■*BluraoihArrribi/wPsikM■Llpcodta:Eachani*rilllFtaapfnhv4.：,r..r■場ihmiciTLMSLimeit;F-slw_6...?...*:FdLlV..Afr?DL1?Hcihod:MTUR>?3pc<iL?(BuA3)SiE&rfew-KTUl23IlBiKi-mE1nnFebj-dBflll￥HD1）存取地址AccessAddress:0xaf9a8c69固定為4個字節(jié)，其值由連接請求數(shù)據(jù)包指定（詳見''一分鐘讀懂低功耗藍(lán)牙連接數(shù)據(jù)包〃）jI■?>-jlEq*阡云TMZJM敏械田！！MilihMilih■；+hLllFall4*fThlWiJILik|*h-WU5w漁叫F心:仲演叫F知&陽inLMjr^wrflJrectJonEnh#^tmuKeMS-t,.CUe?trail：-?^6825.ff3i4lfiuf*jiz頊iuF穌&命uMrix漁W蜒￡砧aTTL6uwruwfdDirac'EitMEitnardikhTuFMiiporifi^BifviPflxrUU-UFng*Mti16fcyttse*rfy1.13?小丁打』16fcytescifrti^eJC12BMtitbirtire^-r-stt口■iBhirtc-pth[5wr?-4lOnt^vtan:ur*rrar-_4mf￡>iE^4d]?C1UHMWLgrntrg^-LintL時W輸"+3」EW.日3心1：蜂|H>ctv-□ddnM.e-1i：Pfh1-fix:b-M-7J-:2S:bcJ]|S1M岫P4W：E^LcrotjM：K村<4ci^ikMeOafiH?9d?r:ItiD?]?m.....-RFU：H...1■HsnDj』:：rru?....4..n-^eQjeixtHtsM?;6...._6._■NextE^pvctfldStq^iincMMirriMr:8hiii6-LLID;Sa?TtfenLZTW*5岐w?占CQWlrteLKV1ik^ecrilthwI.礎(chǔ))泌■RFu：d-!：?431]-Lflr^th:7-OflL:日對4沖村[rSMJJ-1：|pFOrurFt-s]]曲以4#4]l4bL#)-eiuHiwrr-LKtfh-oiosflLLength:JC1W4EQ*lt>J[6(MW4；I?*BlurcacrthATtHbu*MPrirtEiE^JJQpccm!Erchart&HTURafpocFG-(M3)4.._■Aui^HrTticiTLMiSLjriiajr?:F.Im日..1..?CaHMndiTUa..4f>UftU■HfttKd:E?hM^pPfl>JBtapcninServer舊MTiJi23IWhwk如m?—=口&nWH口314TnMat?E>?3ITM7^￡?■nF1WB-...Jrr-G/riKMEIkM^ennl+t?N?i_iM3r-K>iJ4字卞傾蛆K?■巳所MD4?-J■ijK!]#IDIS>2.頭信息DataHeader:0x0712000.....=RFU:0...1....=MoreData:True....0...=SequenceNumber:0

0..=NextExpectedSequenceNumber:010=LLID:StartofanL2CAPmessageoracompleteL2CAPmessagewithnofragmentation(0x2)000.....=RFU:0...00111=Length:7anud1IH-3E3J3JS14WSrwr+hnir*ii-?htnxfa]Lfhf'J,i[?!■>uScun』頑SEPuritnBHHja5W?c4PilIT就4冊"上中孰&*5|AITLE-iJrtEr&TCdrwEtaEHtachiir^i-R1U,￡]L??￥tRinil:LI%?LBE>e沖anud1IH-3E3J3JS14WSrwr+hnir*ii-?htnxfa]Lfhf'J,i[?!■>uScun』頑SEPuritnBHHja5W?c4PilIT就4冊"上中孰&*5|AITLE-iJrtEr&TCdrwEtaEHtachiir^i-R1U,￡]L??￥tRinil:LI%?LBE>e沖E：R1UR?珀明駐、Wwa*際MTU23-I」FfjvMK:]flfar^tvaan5nmm]』1日bytve^iptmd([北Isiti.!-5lunr-fjcvPjSluraca:^|5Evrc?:jric.-?wri_^cif9fE>ofr9)SlurtfiMhLe*iEntriyLintL*y.rIHntarAddmu44::(k(44^iKxhd^73-:^B:bt^]him碩5.1：*27匚卸：網(wǎng)W4fl?：；OerVMMl)?[>d-4皈解1上.-RFU：□.由■山IB!T%flI....4...,■￡r*CTHFK?nLH^?r：/B..-HektbpecupSeqxflceHusbtr-i8-...-.1$，LLIQzSkdrtE"tnL^ljVor■c:-sHpjHt:i<LiCjPM5>jiKduLthm*Fr4n?Titdtam￡ftc2)m.....-RFUsRft0111■-Lwngth:7-E”HgH[EJiptiiflIfrfo[就urKWIuX!/AllOAtAxSL雄kJ/EJjJKoerthLULSFFtct?dLL4hgth!JLEU:MbrahitaIV^bacDj|#感l(wèi)uifwmArt^rtep^kjI■OpciKfl：EichanjvKTUFtflipcnuv.-?^ihe*Tt]cnlc*iSLfMrijr(-；FaIm?■LcwarhdF.Lt.3.L2CAP長度解釋同（請求包）。Length:3Hi1IHhniwi-?lxkf'J*iEn￡>eza.aiuiEurdaicM-_4xjii*9jlrt&unloiEM-i_4xri>9jlr4&llITLE-iJrtcnaiTf]dr?ct3cntachiir^?N1UKfi^MSt,ClLwrtRiHU:U%□—a.仲K.的14E4U冊Z\j9標(biāo)F做溫9AHItE>5衣女MUR4S^HhFiEj8做卜*MW23-■'■■wf■IT?—TM___d.___C!___Jt..I-1?__aZATT1-fa.s___..Ca__l』一—'1?，■》■圖—言、IUilSfir,*FnvMK:ISbycvnontrim[171WtuLbytviicaptmd<1」ISbdti.}ml/itar-fjcvB=RlurMg|5nirc?:jric.-?ri_^ufaiEc&9)jlkfCl^KSfM：Mr^wn_flMi：Ei4M9]■E-ljj?tccthLe*i*EnH-jyLinLLayaricceisMMyii：成|hnt■-AddxAiu4^-:ic.:bd:7^JlOzkK(44.■^.bd:73-:26:bcH[5JmfiiMrcwC-*LcrQe_MI:??4flc；rj；WM'W：W1)dIM做r:敏院i上4N"RFU:□...1—???HQP4DJU!1^14....由.._PJtTHFKWFlLHbcrM故&-融KtEjpecTepSeqxflce8.1$■LLlOzSt^rtpfmLJLtfar■^-sapJatvL±CaPm5>jikb-withra■Fr^tvnkdtim[ftc2)m-....-r>ube…E>Oltl■■bin■皈7-EC；W3W[Fjptin:(HaE^i'tmcKiiiJrt)!葫1urKwhM_,加[日Hom^fLabk-l/EJjjBTacrthL3C￡FPraTdCDLI4i^h!3L[U:MferahitaI^baEaj|qSlura^xhArrfibiXttpeorI?■OpciKfl：Eichanj*HHl1Fbaponhv(6jd63)9…R..r?^ihen-tlcitlD*!SliMrur?-;F-aJw-6.......-(icmnd:FicLar..AfrSDL1?Shed:Ei^har^i-MTUF^spafici-(EtsHS)Sirw4JfTUi￡3[HiMJWEranFpjw'3Ml?n的R火]￡?TUISAlftpW-]?W礦菸無JL.—■…..m■enrnd^：>4.L2CAP通道號解釋同(請求包)。CID:AttributeProtocol(0x0004)Mi1IHJrwr+hnir*ii-?JtMirffcJIxhf'hEr/->I-n.fiSUIEu由iimt_□1*"IrtPurJaiTi_q邊?如Ir4PLE-iJKfiviaTDdriffEtiDntarhir^i-H1URh^hlt,CJlmRiH1U:U&□—a.泗*.的J跳U冊W演tHiFaAITItE>Ch沖&MTUF^SfNhEGjWW0KHTU.23-■i.n、■■?r、■：,、..-i——_A化iu.—rid—gi__j取r__r__ij__.jfah-._____.?_,FriMmi:lbtr^tvan5im137JtalTG^Itibyfcvncaptrnd口北bdii.}ehd/inrfjcvEjeLugg|SEvrc?:jrtc.-iOtaTi_^uif9iE!Ci^)Mnjzwr._flMf&aBc49]AccessRw^FM(i5?|l^>t■-Add—a”4^:ic.:M:7k2C:Ik.bd.72-:2B:bcHhMreK1：*認(rèn)用％御：1?膊(flc；i^；W?W|]』tau潮域r■:土河i上m.-...-rfu：a.a.1....■>由f4真3!T睥-...U...■■￡r*ETHFKI-$&..-融皿t4KCU0SeqwMCttiWrtf-l0-...-.1^，LLldzShirtoi'mL^Li^ar■s-^qaJatvLICaPMsauiKflwithm"fr^nantAtixn[frc2)ffW-....-RFU!B...E>4111-7-5口樞i-WWeInfo(HaE6i*￡rMck￡i*)!弟]""程3』-xitjHME4^lljbbs-]+B'JjjrcccrthL3CBFPtct?dLl4rtfth!JL￡U:AttrahitaFh-wacnj|?Llpcoo■:EichinjnHTljiRaapcnhr,.?i?ihe*Tt]c?LD*iSl^Mrur?-;F-alw.-■CoM?nd:FiflLivKc-zhod:EiichAru?MTUkapunL?5.ATT命令標(biāo)準(zhǔn)：3422MTU屜苦也瞬瀝TheExchangeMTUResponseissentinreplytoareceivedExchangeMTURequest.ParameterSize(octets)DescriptionAttributeQpcode10x0^=ExchangeMTUResponseServerRxMTU2Attributeserve-rreceiveMTUsize-Table3.5:FormatofExchangeMTUResponseTheServerRxMTUshallbegreaterthanorequaltothedefaultATT_MTUTheServerRxMTUparametershallbesettothemaximumsizeoftheattributeprotocolPDUthattheservercanreceive-TheserverandclientshallsetATT_MTUtotheminimumoftheClientRxMTUandtheServerRxMTU.Thesizeisthesametoensurethataclientcancorrectlydetectthefinalpacketofalongattributeread.ThisATT_MTUvalueshallbeappliedintheserverafterthisresponsehasbeensentandbeforeanyotherattributeprotocolPDUissentOuiAJMjiwfc實(shí)例：Opcode:ExchangeMTUResponse(0x03)0=AuthenticationSignature:False.0=Command:False..000011=Method:ExchangeMTUResponse(0x03)*皿"*心甄瓦HniS笑?ir>Vbuufu.iiMiTimS4WH-hnimi-?JrMirfiJbn<>hEn!->l"IK]73.fi3]ZU!jrdaiEHn_qgirP“E#urJifiEhr七噌口fPmPJL1TLE-LHcrwifldmctacnE~ichsr^i-KillRdiqjestaClL?rrtRiKill:LIS：i9ES29.6914E?&AHIBiJNciWiriflliFflCTiE自5迥欽fflURftSpan頃8W脈MTUU■"■M■"■,!Ti-iTEfi.._J____土―unq—*.._■____■*i__￡fi_^-_u；AbITAii-l——Ti,d—--j.-—b__j■.■'_?._r.—-—.-?.li-ATT___..{*__..I_----■I__.A—AMni'i-jXi：^Fpjwm：]fibTjFtviontrim[379m*?!!)』]fitr^tvi^aptiHd(UK用七寸nniJinrfjcv*eiuWOMh|5cum:urfcriOiTi■LhcEnk”LinkLar/ariCCei-5|l\?kH-福d—m.4^-:he..bd^T^jj]:bc(44.■=_bd.73-:2B:bcH[51^^MJrestE.5爭:iff睫IfluOwW"WW：I|*g口Ha獨(dú)皈6?廿4H■RFU:□.IS1a....■Hamc^uiTm_...4.._■￡r?CTHrKi-Hiabvr:$%?-IteKtE^pecTepSeqxnceliWwrie16?LLU:StirtrftnLJljVarjec^alntvLiOkPHSMEduLthra*7■煩intmim[frc2)￥?-KFU,F_..&41tj?L?mth:?-Er；eg奐I滸口(Ha[?i*￡n?CK￡iJri'):「就eniviiUbLtJ與BJurteirthL3CBPPne^KDll4Ogtti：3LEU:Attrabutnh-c±4coj:袖同4|■Arr^ibi/wP^wal■UpcEK?:EichdryjrH1UKtap^nkr9..-,r..r?^ihentlCJTllXiSUMrurt;F-slw-6.._...■■CaHP?r*d:FaLav..4t?DL1???■：hod:Eith*r^?MU(WaponL?(EkiA3)SirvWbi-