`
`W3C®
`
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`
`%&'()*+*,-+.+./)012345
`
`%,6789:;<,9=89>?.@,;(==,@6A;8=;B''<CDEDF;GHHDF
`?.I;<%J
`%&'(;45)KL.,;D001
`
`MNOPQRSTPOUVW
`NXXYWZZ[[[\[]\UT^ZM_Z`aMbcYOYSdOVOV^cefghij
`Q
`klmWQnOYSdOVS\NXodpRQq\jfQqeefZgrZgeQqfWshWgiQtOdduvdXQbwYQk
`xuXSPXQRSTPOUVW
`NXXYWZZ[[[\[]\UT^ZM_Z`aMbcYOYSdOVOV^
`yvXNUTPW
`zSVTO{Q|T}PX}{Q`OSdPSVpQ~]pQ€tT}PX}{[]\UT^‚p
`- - - - -
`Q
`ƒOoQ„SXX}PpQ…OPOXOV^Q†‡OSVXOPXpQ~]pQˆO^OXudQb‰vOYoSVXQUTYUTuXOUVpQ€Š^[]\UT^‚p
`yVPSdoQ‹uOTmc†oOXNpQ~]pQ€uŒuOTm[]\UT^‚p
`Q
`bTO‡QnTvmNUooSuvwpQ~]pQ€STO‡[]\UT^‚p
`zŽ{UVQ~OvoQxOSpQ~]pQ€NU[‡UoS[]\UT^‚p
`NTOPQxOddS}pQ~]pQ€‡NTOP[]\UT^‚
`
`H6?6LA;8=;'+A;8@L>,.6
`
`MNOPQmU‡voSVXQOPQuQ`aMbQoumSQuRuOduŒdSQŒ}QXNSQ~]QUVPUTXOvoQtUTQmOP‡vPPOUVQUVd}\QMNOPQOVmO‡uXSPQVU
`SVmUTPSoSVXQUtQOXPQ‡UVXSVXpQVUTQXNuXQXNSQUVPUTXOvoQNuPpQOPpQUTQ[OddQŒSQuddU‡uXOV^QuV}QTSPUvT‡SPQXUQXNSQOPPvSP
`ummTSPPSmQŒ}QXNSQ`aMb\QyQdOPXQUtQ‡vTTSVXQ`aMbPQ‡uVQŒSQtUvVmQuXWQNXXYWZZ[[[\[]\UT^ZM_Z
`
`†OV‡SQ`aMbPQuTSQPvŒŠS‡XQXUQtTS‰vSVXQ‡NuV^SpQ}UvQuTSQumROPSmQXUQTStSTSV‡SQXNSQuŒURSQ‘_xpQTuXNSTQXNuVQXNSQ‘_xP
`tUTQ`aMbPQXNSoPSdRSP\QMNSQTSPvdXPQNSTSQuTSQYTUROmSmQtUTQ‡UoovVOX}QOVXSTSPXpQXNUv^NQOXQNuPQVUXQŒSSVQTO^UTUvPd}
`RudOmuXSmQuVmQPNUvdmQVUXQudUVSQŒSQvPSmQXUQou{SQ‡UooST‡OudQmS‡OPOUVP\QlVQummOXOUVpQXNSQSwu‡XQTSPvdXPQuTS
`UŒROUvPd}QuQtvV‡XOUVQUtQXNSQXSPXPQYSTtUToSm’Q}UvTQoOdSu^SQ[OddQRuT}\
`
`MUQuYYSuTQOVQy“Q†l„a““QefQnTU‡SmOV^P\
`
`”•A69?@6
`
`~SQmSP‡TOŒSQUvTQOVRSPXO^uXOUVQUtQXNSQSttS‡XQUtQYSTPOPXSVXQ‡UVVS‡XOUVPpQYOYSdOVOV^QuVmQdOV{QdSRSdQmU‡voSVX
`‡UoYTSPPOUVQUVQUvTQ‡dOSVXQuVmQPSTRSTQzMMnQOoYdSoSVXuXOUVP\QyQPOoYdSQXSPXQPSXvYQOPQvPSmQXUQRSTOt}QzMMnZq\qP
`mSPO^VQuVmQvVmSTPXuVmQzMMnZq\qQOoYdSoSVXuXOUVQPXTuXS^OSP\Q~SQYTSPSVXQMnQuVmQTSudQXOoSQYSTtUTouV‡SQmuXu
`ŒSX[SSVQXNSQdOŒ[[[QTUŒUXQ–if—QuVmQŒUXNQXNSQ~]PQƒO^Pu[Q–ir—QuVmQyYu‡NSQ–ie—QzMMnQPSTRSTPQvPOV^
`zMMnZq\gpQzMMnZq\qQ[OXNQYSTPOPXSVXQ‡UVVS‡XOUVPpQzMMnZq\qQ[OXNQYOYSdOVSmQTS‰vSPXPpQuVmQzMMnZq\qQ[OXN
`YOYSdOVSmQTS‰vSPXPQuVmQmStduXSQmuXuQ‡UoYTSPPOUVQ–ii—\Q~SQudPUQOVRSPXO^uXSQ[NSXNSTQXNSQMnQ`u^dSQud^UTOXNoQNuP
`uVQSttS‡XQUVQzMMnZq\qQYSTtUTouV‡S\Q~NOdSQPUoS[NuXQuTXOtO‡OudQuVmQYUPPOŒd}QURSTPXuXOV^QXNSQŒSVStOXPQUt
`zMMnZq\qpQ[SQŒSdOSRSQXNSQXSPXPQuVmQTSPvdXPQuYYTUwOouXSQPUoSQ‡UooUVQŒSNuROUTQPSSVQOVQŒTU[PSTP\QMNSQTSPvdXP
`‡UVtOToQXNuXQzMMnZq\qQOPQoSSXOV^QOXPQouŠUTQmSPO^VQ^UudP\QavTQSwYSTOSV‡SQNuPQŒSSVQXNuXQOoYdSoSVXuXOUVQmSXuOdP
`uTSQRST}QOoYUTXuVXQXUQu‡NOSRSQuddQUtQXNSQŒSVStOXPQUtQzMMnZq\q\
`
`|UTQuddQUvTQXSPXPpQuQYOYSdOVSmQzMMnZq\qQOoYdSoSVXuXOUVQUvXYSTtUToSmQzMMnZq\gpQSRSVQ[NSVQXNSQzMMnZq\g
`OoYdSoSVXuXOUVQvPSmQovdXOYdSQ‡UVVS‡XOUVPQOVQYuTuddSdpQvVmSTQuddQVSX[UT{QSVROTUVoSVXPQXSPXSm\QMNSQPuROV^PQ[STS
`
`
`
`  
`! 
`
`
`"  
` #"#
`
` $
`
`

`

`   
`
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`
`%&’()%*&’%’+%,&-.’-+’&/-0’%12’*-3)&43)*’%*’35,6’%*’%’+%,&-.’-+’&)10’41’&).3*’-+’7%,8)&*’&.%1*34&&)29’:(%7*)2’&43)
`437.-;)3)1&’4*’()**’2.%3%&4,0’%12’*&.-1<(=’2)7)12*’-1’=-5.’1)&/-.8’,-11),&4-19
`
`>-3)’2%&%’4*’7.)*)1&)2’*6-/41<’+5.&6).’*%;41<*’7-**4?()’?=’,6%1<)*’41’@)?’,-1&)1&0’*7),4+4,%((=’?=’&6)’5*)’-+
`A>>’*&=()’*6))&*’BCDE0’%12’&6)’3-.)’,-37%,&’FGH’BIDE’43%<)’.)7.)*)1&%&4-10’?-&6’.),)1&’.),-33)12%&4-1*’-+
`@JA9’K43)’242’1-&’%((-/’+5((’)12’&-’)12’2%&%’,-((),&4-1’-1’&6)*)’,%*)*9’K6)’.)*5(&*’*6-/’&6%&’LKKFMC9C’%12
`,6%1<)*’41’@)?’,-1&)1&’/4((’6%;)’2.%3%&4,’.)*5(&*’41’N1&).1)&’%12’@)?’7).+-.3%1,)’%*’LKKFMC9C’%12’.)(%&)2
`&),61-(-<4)*’2)7(-=’-;).’&6)’1)%.’+5&5.)9’O14;).*%(’5*)’-+’*&=()’*6))&*0’);)1’/4&6-5&’2)7(-=3)1&’-+’LKKFMC9C0
`/-5(2’,%5*)’%’;).=’*4<14+4,%1&’.)25,&4-1’41’1)&/-.8’&.%++4,9
`
`K64*’7%7).’2-)*’1-&’41;)*&4<%&)’+5.&6).’7).+-.3%1,)’%12’1)&/-.8’*%;41<*’)1%?()2’?=’&6)’437.-;)2’,%,641<
`+%,4(4&4)*’7.-;42)2’?=’&6)’LKKFMC9C’7.-&-,-(0’-.’?=’*-764*&4,%&)2’5*)’-+’.%1<)’.)P5)*&*9
`
`QRSTUVWXSYUR
`
`K=74,%(’/)?’7%<)*’&-2%=’,-1&%41’%’L=7).K)Z&’[%.857’\%1<5%<)’]LK[\^’2-,53)1&0’%12’3%1=’)3?)22)2
`43%<)*9’K/)1&=’-.’3-.)’)3?)22)2’43%<)*’%.)’P54&)’,-33-19’:%,6’-+’&6)*)’43%<)*’4*’%1’412)7)12)1&’-?_),&’41
`&6)’@)?0’.)&.4);)2’]-.’;%(42%&)2’+-.’,6%1<)^’*)7%.%&)(=9’K6)’,-33-1’?)6%;4-.’+-.’%’/)?’,(4)1&0’&6).)+-.)0’4*’&-
`+)&,6’&6)’?%*)’LK[\’2-,53)1&0’%12’&6)1’433)24%&)(=’+)&,6’&6)’)3?)22)2’-?_),&*0’/64,6’%.)’&=74,%((=’(-,%&)2
`-1’&6)’*%3)’*).;).9
`
`K6)’(%.<)’153?).’-+’)3?)22)2’-?_),&*’.)7.)*)1&*’%’,6%1<)’+.-3’&6)’)1;4.-13)1&’41’/64,6’&6)’@)?’&.%1*+).
`7.-&-,-(0’&6)’L=7).&)Z&’K.%1*+).’F.-&-,-(’]LKKF^’/%*’2)*4<1)29’`*’%’.)*5(&0’LKKFMC9D’6%12()*’35(&47()
`.)P5)*&*’+.-3’&6)’*%3)’*).;).’41)++4,4)1&(=0’,.)%&41<’%’*)7%.%&)’KAF’,-11),&4-1’+-.’)%,6’-?_),&9
`
`K6)’.),)1&(=’.)()%*)2’LKKFMC9C’*&%12%.2’/%*’2)*4<1)2’&-’%22.)**’&64*’7.-?()3’?=’)1,-5.%<41<’35(&47()
`&.%1*+).*’-+’-?_),&*’-;).’-1)’,-11),&4-19’A-41,42)1&%((=0’)Z7),&)2’,6%1<)*’41’@)?’,-1&)1&’%.)’)Z7),&)2’&-
`2),.)%*)’&6)’153?).’-+’)3?)22)2’-?_),&*0’/64,6’/4((’437.-;)’1)&/-.8’7).+-.3%1,)9’K6)’,6)%7)*&’-?_),&’4*’-1)
`&6%&’4*’1-’(-1<).’1))2)29
`
`K-’&)*&’&6)’)++),&*’-+’*-3)’-+’&6)’1)/’+)%&5.)*’-+’LKKFMC9C0’/)’*435(%&)2’&/-’24++).)1&’&=7)*’-+’,(4)1&’?)6%;4-.a
`;4*4&41<’%’*4&)’+-.’&6)’+4.*&’&43)0’/6).)’1-&641<’4*’41’&6)’,(4)1&’,%,6)0’%12’.);%(42%&41<’,%,6)2’4&)3*’/6)1’%’*4&)’4*
`.);4*)29’K)*&*’/).)’,-125,&)2’41’&6.))’24++).)1&’1)&/-.8’)1;4.-13)1&*’2)*4<1)2’&-’*7%1’%’.%1<)’-+’,-33-1’/)?
`5*)*a’%’(-,%(’:&6).1)&’]\`G^0’&.%1*,-1&41)1&%(’N1&).1)&’]@`G^0’%12’%’Ib9b’c?7*’24%(57’(418’5*41<’&6)’F-41&d&-d
`F-41&’F.-&-,-(’]FFF^9
`
`N1’&64*’7%7).0’/)’7.)*)1&’&6)’+41%(’.)*5(&*0’%12’*-3)’-+’&6)’&6-5<6&’7.-,)**)*’&6%&’/)’/)1&’&6.-5<6’/64()’&)*&41<
`%12’-7&434e41<’-5.’437()3)1&%&4-1*9’f5.’6-7)’4*’&6%&’-5.’)Z7).4)1,)’3%=’<542)’-&6).*’&6.-5<6’&6)4.’-/1
`437()3)1&%&4-1’)++-.&*’%12’6)(7’&6)3’%;-42’*-3)’1-1d-?;4-5*’7).+-.3%1,)’74&*’/)’+)((’41&-9’g5.&6).
`41+-.3%&4-10’&6)’2%&%’4&*)(+’]%12’(%&).’2%&%’,-((),&4-1’.51*^’,%1’?)’+-512’-1’&6)’@)?’BIhE9
`
`ijkRlmnoSUopqqr
`
`LKKFMC9C’BsE’4*’%1’57/%.2’,-37%&4?()’7.-&-,-(’&-’LKKFMC9D’BJE9’t-&6’LKKFMC9D’%12’LKKFMC9C’5*)’&6)’KAF
`7.-&-,-(’BCIE’+-.’2%&%’&.%1*7-.&9’L-/);).0’&6)’&/-’;).*4-1*’-+’LKKF’5*)’KAF’24++).)1&(=9
`
`LKKFMC9D’-7)1*’%12’,(-*)*’%’1)/’KAF’,-11),&4-1’+-.’)%,6’-7).%&4-19’>41,)’3-*&’@)?’-?_),&*’%.)’*3%((0’&64*
`7.%,&4,)’3)%1*’%’64<6’+.%,&4-1’-+’7%,8)&*’%.)’*437(=’KAF’,-1&.-(’7%,8)&*’5*)2’&-’-7)1’%12’,(-*)’%’,-11),&4-19
`g5.&6).3-.)0’/6)1’%’KAF’,-11),&4-1’4*’+4.*&’-7)1)20’KAF’)37(-=*’%1’%(<-.4&63’81-/1’%*’*(-/’*&%.&’BCCE9’>(-/
`*&%.&’5*)*’&6)’+4.*&’*);).%(’2%&%’7%,8)&*’&-’7.-?)’&6)’1)&/-.8’&-’2)&).341)’&6)’-7&43%(’&.%1*34**4-1’.%&)9’`<%410
`?),%5*)’@)?’-?_),&*’%.)’*3%((0’3-*&’-?_),&*’%.)’&.%1*+)..)2’?)+-.)’&6)4.’KAF’,-11),&4-1’,-37()&)*’&6)’*(-/
`*&%.&’%(<-.4&639’N1’-&6).’/-.2*0’3-*&’LKKFMC9D’-7).%&4-1*’5*)’KAF’%&’4&*’()%*&’)++4,4)1&9’K6)’.)*5(&*’6%;)’?))1
`3%_-.’7.-?()3*’25)’&-’.)*5(&41<’,-1<)*&4-1’%12’511),)**%.=’-;).6)%2’BuE9
`
`
`
`  
`! 
`
`
`"  
` #"#
`
` $
`
`

`

`5/3/2021
`Network Performance Effects of HTTP/1.1, CSS1, and PNG
`   
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`HTTP/1.1 leaves the TCP connection open between consecutive operations. This techniqueis called "persistent
`%&&'()*)+,-./-0+12-+&3'+4566-41756+58-6+9-1:--6+4560-4;17/-+58-<.17560*+&270+1-4267=;-+70+4.,,->+?8-<0701-61
`connections," which both avoids the costs of multiple opens and closes and reduces the impact of slowstart.
`4566-417560@?+:2742+9512+./57>0+12-+45010+5A+B;,178,-+58-60+.6>+4,50-0+.6>+<->;4-0+12-+7B8.41+5A+0,5:+01.<1*
`Persistent connections are moreefficient than the current practice of running multiple short TCP connections in
`'-<0701-61+4566-417560+.<-+B5<-+-AA747-61+12.6+12-+4;<<-61+8<.4174-+5A+<;6676C+B;,178,-+025<1+&3'+4566-417560+76
`parallel.
`8.<.,,-,*
`Byleaving the TCP connection open between requests, many packets can be avoided, while avoiding multiple
`DE+,-./76C+12-+&3'+4566-41756+58-6+9-1:--6+<-=;-010@+B.6E+8.4F-10+4.6+9-+./57>->@+:27,-+./57>76C+B;,178,-
`RTTs due to TCPslowstart. The first few packet exchanges of a new TCP connectionare either too fast, or too
`G&&0+>;-+15+&3'+0,5:+01.<1*+&2-+A7<01+A-:+8.4F-1+-H42.6C-0+5A+.+6-:+&3'+4566-41756+.<-+-712-<+155+A.01@+5<+155
`slow for that path. If these exchangesare too fast for the route (commonin today's Internet), they contribute to
`0,5:+A5<+12.1+8.12*+IA+12-0-+-H42.6C-0+.<-+155+A.01+A5<+12-+<5;1-+J45BB56+76+15>.EK0+I61-<6-1L@+12-E+4561<79;1-+15
`Internet congestion.
`I61-<6-1+456C-01756*
`Conversely, since most connectionsare in slow start at any given time in HTTP/1.0 not using persistent
`356/-<0-,E@+0764-+B501+4566-417560+.<-+76+0,5:+01.<1+.1+.6E+C7/-6+17B-+76+%&&'()*M+651+;076C+8-<0701-61
`connections, keeping a dialup PPP link busy has required running multiple TCP connections simultaneously
`4566-417560@+F--876C+.+>7.,;8+'''+,76F+9;0E+2.0+<-=;7<->+<;6676C+B;,178,-+&3'+4566-417560+07B;,1.6-5;0,E
`(typical implementations have used 4 TCP connections). This can exacerbate the congestion problem further.
`J1E874.,+7B8,-B-61.17560+2./-+;0->+N+&3'+4566-417560L*+&270+4.6+-H.4-<9.1-+12-+456C-01756+8<59,-B+A;<12-<*
`The "Keep-Alive" extension to HTTP/1.0 is a form of persistent connections. HTTP/1.1's design differs in minor
`&2-+?O--8PQ,7/-?+-H1-60756+15+%&&'()*M+70+.+A5<B+5A+8-<0701-61+4566-417560*+%&&'()*)K0+>-07C6+>7AA-<0+76+B765<
`details from Keep-Alive to overcome a problem discovered when Keep-Alive is used with more than one proxy
`>-1.7,0+A<5B+O--8PQ,7/-+15+5/-<45B-+.+8<59,-B+>7045/-<->+:2-6+O--8PQ,7/-+70+;0->+:712+B5<-+12.6+56-+8<5HE
`between a client and a server.
`9-1:--6+.+4,7-61+.6>+.+0-</-<*
`Persistent connections allow multiple requests to be sent without waiting for a response; multiple requests and
`'-<0701-61+4566-417560+.,,5:+B;,178,-+<-=;-010+15+9-+0-61+:7125;1+:.7176C+A5<+.+<-08560-R+B;,178,-+<-=;-010+.6>
`responses can be contained in a single TCP segment. This can be used to avoid manyroundtrip delays,
`<-08560-0+4.6+9-+4561.76->+76+.+076C,-+&3'+0-CB-61*+&270+4.6+9-+;0->+15+./57>+B.6E+<5;6>+1<78+>-,.E0@
`improving performance, and reducing the numberof packets further. This techniqueis called "pipelining" in
`7B8<5/76C+8-<A5<B.64-@+.6>+<->;476C+12-+6;B9-<+5A+8.4F-10+A;<12-<*+&270+1-4267=;-+70+4.,,->+?878-,7676C?+76
`HTTP.
`%&&'*
`HTTP/1.1 also enables transport compression of data types so those clients can retrieve HTML(orother)
`%&&'()*)+.,05+-6.9,-0+1<.6085<1+45B8<-00756+5A+>.1.+1E8-0+05+1250-+4,7-610+4.6+<-1<7-/-+%&ST+J5<+512-<L
`uncompressed documents using data compression; HTTP/1.0 does not havesufficient facilities for transport
`;645B8<-00->+>54;B-610+;076C+>.1.+45B8<-00756R+%&&'()*M+>5-0+651+2./-+0;AA747-61+A.47,717-0+A5<+1<.6085<1
`compression. Further work is continuing in this area [26].
`45B8<-00756*+U;<12-<+:5<F+70+456176;76C+76+1270+.<-.+VWXY*
`The major HTTP/1.1 design goals therefore include:
`&2-+B.Z5<+%&&'()*)+>-07C6+C5.,0+12-<-A5<-+764,;>-[
`•
`e
`lower HTTP's load on the Internet for the same amountof "real work", while solving the congestion
`,5:-<+%&&'K0+,5.>+56+12-+I61-<6-1+A5<+12-+0.B-+.B5;61+5A+?<-.,+:5<F?@+:27,-+05,/76C+12-+456C-01756
`caused by HTTP
`4.;0->+9E+%&&'
`•
`e HTTP/1.0's caching is primitive and error prone; HTTP/1.1 enable applications to work reliably with
`%&&'()*MK0+4.4276C+70+8<7B717/-+.6>+-<<5<+8<56-R+%&&'()*)+-6.9,-+.88,74.17560+15+:5<F+<-,7.9,E+:712
`caching
`4.4276C
`•
`e end user performance must improve,orit is unlikely that HTTP/1.1 will be deployed
`-6>+;0-<+8-<A5<B.64-+B;01+7B8<5/-@+5<+71+70+;6,7F-,E+12.1+%&&'()*)+:7,,+9-+>-8,5E->
`HTTP/1.1 provides significant improvements to HTTP/1.0 to allow applications to workreliably in the face of
`%&&'()*)+8<5/7>-0+07C67A74.61+7B8<5/-B-610+15+%&&'()*M+15+.,,5:+.88,74.17560+15+:5<F+<-,7.9,E+76+12-+A.4-+5A
`caching, and to allow applications to mark more content cacheable. Today, caching is often deliberately defeated
`4.4276C@+.6>+15+.,,5:+.88,74.17560+15+B.<F+B5<-+4561-61+4.42-.9,-*+&5>.E@+4.4276C+70+5A1-6+>-,79-<.1-,E+>-A-.1->
`in order to achievereliability. This paper does not explore these effects.
`76+5<>-<+15+.427-/-+<-,7.97,71E*+&270+8.8-<+>5-0+651+-H8,5<-+12-0-+-AA-410*
`HTTP/1.1 does not attempt to solve some commonly seen problems, such as transient network overloadsat
`%&&'()*)+>5-0+651+.11-B81+15+05,/-+05B-+45BB56,E+0--6+8<59,-B0@+0;42+.0+1<.607-61+6-1:5<F+5/-<,5.>0+.1
`popular web sites with topical news(e.g. the Schumacher-Levy comet impact on Jupiter), but should at least
`858;,.<+:-9+071-0+:712+15874.,+6-:0+J-*C*+12-+\42;B.42-<PT-/E+45B-1+7B8.41+56+];871-<L@+9;1+025;,>+.1+,-.01
`help these problems.
`2-,8+12-0-+8<59,-B0*
`This paper presents measuredresults of the consequences of HTTP/1.1 transport protocol additions. Many of
`&270+8.8-<+8<-0-610+B-.0;<->+<-0;,10+5A+12-+4560-=;-64-0+5A+%&&'()*)+1<.6085<1+8<51545,+.>>717560*+S.6E+5A
`these additions have been available as extensions to HTTP/1.0, but this paper showsthe possible synergy when
`12-0-+.>>717560+2./-+9--6+./.7,.9,-+.0+-H1-607560+15+%&&'()*M@+9;1+1270+8.8-<+025:0+12-+850079,-+0E6-<CE+:2-6
`the extensions to the HTTP protocol are used in concert, and in with changesin content.
`12-+-H1-607560+15+12-+%&&'+8<51545,+.<-+;0->+76+4564-<1@+.6>+76+:712+42.6C-0+76+4561-61*
`Range Requests and Validation
`^_`abc^bdebfgfc_`hci_jkh_gkl`
`To improve the perceived response time, a browserneedsto learn basic size information of each object in a page
`&5+7B8<5/-+12-+8-<4-7/->+<-08560-+17B-@+.+9<5:0-<+6-->0+15+,-.<6+9.074+07m-+76A5<B.1756+5A+-.42+59Z-41+76+.+8.C-
`(required for page layout) as soon as possible. The first bytes typically contain the image size. To achieve better
`J<-=;7<->+A5<+8.C-+,.E5;1L+.0+0556+.0+850079,-*+&2-+A7<01+9E1-0+1E874.,,E+4561.76+12-+7B.C-+07m-*+&5+.427-/-+9-11-<
`concurrencyandretrieve the first few bytes of embeddedlinks whilestill receiving the bytes for the master
`4564;<<-64E+.6>+<-1<7-/-+12-+A7<01+A-:+9E1-0+5A+-B9->>->+,76F0+:27,-+017,,+<-4-7/76C+12-+9E1-0+A5<+12-+B.01-<
`document, HTTP/1.0 browsers usually use multiple TCP connections. We believe by using range requests
`>54;B-61@+%&&'()*M+9<5:0-<0+;0;.,,E+;0-+B;,178,-+&3'+4566-417560*+n-+9-,7-/-+9E+;076C+<.6C-+<-=;-010
`HTTP/1.1 clients can achieve similar or better results over a single connection.
`%&&'()*)+4,7-610+4.6+.427-/-+07B7,.<+5<+9-11-<+<-0;,10+5/-<+.+076C,-+4566-41756*
`
`https://www.w3.org/Protocols/HTTP/Performance/Pipeline
`
`  
`! 
`
`
`"  
` #"#
`
`Petitioners Ex-] O ] 6, Page 3 of 19
`
`3/19
` $
`
`

`

`   
`
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`
`&''()*+,+)-./01.2)32)4356)7/)68.)2631-35-)931-):726);<55.16)&''(*+,=)2.5>.52)3?5.3-@)0:4?.:.16A)B@6.)531C.
`/3;0?060.2)6836)3??7D)3);?0.16)67)4.5/75:)435603?)5.650.>3?)7/)7BE.;62,)'8.)010603?)016.16)7/)531C.)5.F<.262)D32)67
`3??7D);3;801C)457G@)67)/01028)016.55<46.-)65312/.52)B@)5.F<.2601C)71?@)68.)B@6.2)7/)68.)-7;<:.16)68.@);<55.16?@
`-7)176)87?-)01)68.05);3;8.,
`
`'7)27?>.)68.)457B?.:)6836)B57D2.52)1..-)68.)20H.)7/).:B.--.-)7BE.;62I)D.)B.?0.>.)6836)68.)136<53?)5.>3?0-36071
`5.F<.26)/75)&''(*+,+)D0??);7:B01.)B768);3;8.)>3?0-36071)8.3-.52)31-)31)JKLMNOPQR5.F<.26)8.3-.5I)67)45.>.16
`?35C.)7BE.;62)/57:):71747?0H01C)68.);711.;6071)67)68.)2.5>.5)7>.5)062);711.;6071,)'8.)531C.)5.F<.26.-)287<?-)B.
`?35C.).17<C8)67)<2<3??@)5.6<51)31@).:B.--.-):.63-363)/75)68.)7BE.;6)/75)68.);7::71)-363)6@4.2,)'802);343B0?06@
`7/)&''(*+,+)02)0:4?0;06)01)062);3;801C)31-)531C.)5.F<.26)-.20C1,
`
`S8.1)3)B57D2.5)5.>02062)3)43C.I)06)832)3)>.5@)C77-)0-.3)D836)68.)6@4.)7/)31@).:B.--.-)7BE.;6)02)?0T.?@)67)B.I)31-
`;31)68.5./75.)B768):3T.)3)>3?0-36071)5.F<.26)31-)3?27)20:<?631.7<2?@)5.F<.26)68.):.63-363)7/)68.).:B.--.-
`7BE.;6)0/)68.5.)832)B..1)31@);831C.,)'8.):.63-363)02):<;8):75.)>3?<3B?.)6831)68.).:B.--.-)0:3C.)-363,
`U<B2.F<.16?@I)68.)B57D2.5):0C86)C.1.536.)5.F<.262)/75)68.)5.26)7/)68.)7BE.;6I)75)/75).17<C8)7/).3;8)7BE.;6)67
`3??7D)/75)457C5.220>.)-024?3@)7/)0:3C.)-363)6@4.2)9.,C,)457C5.220>.)(VWI)WXY)75)Z([W)0:3C.2AI)75)67):<?604?.G
`B.6D..1):<?604?.)?35C.)0:3C.2)71)68.)43C.,)S.);3??)6802)26@?.)7/)<2.)7/)&''(*+,+)\4775):31]2):<?604?.G01C,\
`
`S.)B.?0.>.);3;8.)>3?0-36071);7:B01.-)D068)531C.)5.F<.262)D0??)?0T.?@)B.;7:.)3)>.5@);7::71)0-07:)7/
`&''(*+,+,
`
`^_`abcdRefRgchR^faecae
`
`i7<C8?@)20:<?631.7<2?@)67)68.)-.4?7@:.16)7/)68.)&''(*+,+)45767;7?I)9B<6)176)-.4.1-.16)<471)06AI)68.)S.B)D0??
`2..)68.)-.4?7@:.16)7/)j32;3-01C)U6@?.)U8..62)9jUUA)kl=m)31-)1.D)0:3C.)31-)310:36071)/75:362)2<;8)32
`(7563B?.)V.6D75T)W53480;2)9(VWA)kn=m)31-)o<?604?.p0:3C.)V.6D75T)W53480;2)9oVWA)kl+m,
`
`X1)68.)2;0.160/0;).1>0571:.16)D8.5.)68.)S.B)D32)B751I)4.74?.)D.5.)C.1.53??@):75.);71;.51.-)D068)68.);716.16
`7/)68.05)-7;<:.162)6831)68.)45.2.1636071,)X1)3)5.2.35;8)5.4756I)68.);870;.)7/)/7162):366.52)?.22)6831)68.)5.2<?62
`B.01C)5.4756.-I)27).35?@)>.520712)7/)&@4.5'.G6)o35T<4)q31C<3C.)9&'oqA)2<//0;.-)/75):726)2;0.160262,
`&7D.>.5I)D8.1)171p2;0.160/0;);7::<1060.2)-02;7>.5.-)68.)S.BI)68.)4.5;.0>.-)?0:06360712)7/)&'oq)B.;3:.)3
`27<5;.)7/)/5<26536071,)S.B)43C.)-.20C1.52)D068)3)B3;TC57<1-)01)434.5pB32.-)-.2T674)4<B?02801C)D316.-):75.
`;71657?)7>.5)68.)45.2.1636071)7/)68.05)-7;<:.162)6831)&'oq)D32):.316)67)457>0-.,)j32;3-01C)U6@?.)U8..62
`9jUUA)7//.5):31@)7/)68.);343B0?060.2)5.F<.26.-)B@)43C.)-.20C1.52)B<6)02)71?@)17D)2..01C)D0-.245.3-
`0:4?.:.1636071,
`
`X1)68.)3B2.1;.)7/)26@?.)28..62I)3<68752)83>.)83-)67):..6)-.20C1);83??.1C.2)B@)6D02601C)&'oq)7<6)7/)2834.I)/75
`012631;.I)B@)26<--01C)68.05)43C.2)D068)2:3??)0:3C.2)6836)-7)?066?.):75.)6831)-024?3@)6.G6,)X1)6802)2.;6071)7/)68.
`26<-@I)D.).260:36.)87D)S.B)4.5/75:31;.)D0??)B.)3//.;6.-)B@)68.)01657-<;6071)7/)jUU,)S.)D0??)176)-02;<22)768.5
`B.1./062)67)B.)5.34.-)D068)26@?.)28..62I)2<;8)32)C5.36.5)3;;.220B0?06@I)0:457>.-)4501601CI)31-).320.5)206.
`:313C.:.16,
`
`r1)68.)D.BI):726)0:3C.2)35.)01)WXY)/75:36,)s)1.D)0:3C.)/75:36I)(VWI)832)2.>.53?)3->3163C.2)7>.5)WXY,)(VW
`0:3C.2)5.1-.5):75.)F<0;T?@)71)68.)2;5..1)31-)p)B.20-.2)457-<;01C)80C8.5)F<3?06@I);5722p4?36/75:)0:3C.2)p)(VW
`0:3C.2)35.)<2<3??@)2:3??.5)6831)WXY)0:3C.2,
`
`oVW)02)31)310:36071)/75:36)01)68.)(VW)/3:0?@I)D80;8)p)3?71C)D068)768.5)3->3163C.2)p)02):75.);7:43;6)6831
`310:36.-)WXY,
`
`tuvfuRgfuw
`
`-
`(3-:313B831)31-)o7C<?)k+m)287D)5.2<?62)/57:)3)457676@4.)0:4?.:.1636071)D80;8).G6.1-.-)&''()67)2<44756
`B768)4.52026.16);711.;60712)31-)404.?0101CI)31-)26<-@)?36.1;0.2I)6857<C84<6I)31-)2@26.:)7>.58.3-)022<.2)01>7?>.-
`01)4.52026.16);711.;60712,)'802)313?@202)/75:.-)68.)B320;)-363)31-)E<260/0;36071)B.801-)&''(*+,+]2)4.52026.16
`
`  
`! 
`
`
`"  
` #"#
`
`$ %
`
`

`

`5/3/2021
`Network Performance Effects of HTTP/1.1, CSS1, and PNG
`   
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`connection andpipelining design. HTTP/1.1 primarily relies on pipelining rather than introducing new HTTP
`%&''(%)*&'+,'-+.*.(/*'*'0+-(1*0'2+34456727+.8*9,8*/:+8(/*(1+&'+.*.(/*'*'0+8,);(8+);,'+*')8&-<%*'0+'(=+3445
`methodsto achieve the performance benefits documented below. Asthis paper makesclear, both pipelining and
`9();&-1+)&+,%;*(>(+);(+.(8?&89,'%(+@('(?*)1+-&%<9(')(-+@(/&=2+A1+);*1+.,.(8+9,B(1+%/(,8C+@&);+.*.(/*'*'0+,'-
`persistent connections are needed to achieve high performanceover a single HTTP connection.
`.(81*1)(')+%&''(%)*&'1+,8(+'((-(-+)&+,%;*(>(+;*0;+.(8?&89,'%(+&>(8+,+1*'0/(+3445+%&''(%)*&'2
`Pipelining, or batching, have been successfully used in a numberof other systems, notably graphics protocols
`5*.(/*'*'0C+&8+@,)%;*'0C+;,>(+@(('+1<%%(11?<//:+<1(-+*'+,+'<9@(8+&?+&);(8+1:1)(91C+'&),@/:+08,.;*%1+.8&)&%&/1
`such as the X Window System [15] or Trestle [16], in its original RPC based implementation.
`1<%;+,1+);(+D+E*'-&=+F:1)(9+G7HI+&8+48(1)/(+G7JIC+*'+*)1+&8*0*',/+K5L+@,1(-+*9./(9('),)*&'2
`Touch, Heidemann, and Obraczka[5] explore a numberofpossible changes that might help HTTP behavior,
`4&<%;C+3(*-(9,''C+,'-+M@8,%NB,+GHI+(O./&8(+,+'<9@(8+&?+.&11*@/(+%;,'0(1+);,)+9*0;)+;(/.+3445+@(;,>*&8C
`including the sharing of TCP control blocks [19] and Transaction TCP (T/TCP) [17], [18]. The extended length
`*'%/<-*'0+);(+1;,8*'0+&?+4L5+%&')8&/+@/&%B1+G7PI+,'-+48,'1,%)*&'+4L5+Q464L5R+G7SIC+G7TI2+4;(+(O)('-(-+/('0);
`of deployment of changes to TCP argued against any dependency of HTTP/1.1 on either of these; however, we
`&?+-(./&:9(')+&?+%;,'0(1+)&+4L5+,80<(-+,0,*'1)+,':+-(.('-('%:+&?+34456727+&'+(*);(8+&?+);(1(U+;&=(>(8C+=(
`believe that both mechanisms may improve performance, independently to the improvements made by
`@(/*(>(+);,)+@&);+9(%;,'*191+9,:+*9.8&>(+.(8?&89,'%(C+*'-(.('-(')/:+)&+);(+*9.8&>(9(')1+9,-(+@:
`HTTP/1.1. T/TCP might help reduce latency whenrevisiting a Webserverafter the server has closedits
`344567272+464L5+9*0;)+;(/.+8(-<%(+/,)('%:+=;('+8(>*1*)*'0+,+E(@+1(8>(8+,?)(8+);(+1(8>(8+;,1+%/&1(-+*)1
`connection. Sharing of TCP control blocks would primarily help HTTP/1.0, however, since the HTTP/1.1 limits
`%&''(%)*&'2+F;,8*'0+&?+4L5+%&')8&/+@/&%B1+=&</-+.8*9,8*/:+;(/.+3445672VC+;&=(>(8C+1*'%(+);(+34456727+/*9*)1
`the numberof connections betweena client/serverpair.
`);(+'<9@(8+&?+%&''(%)*&'1+@()=(('+,+%/*(')61(8>(8+.,*82
`In independent work, Heidemann [7] describes the interactions of persistent connections with Nagle's algorithm.
`W'+*'-(.('-(')+=&8BC+3(*-(9,''+GSI+-(1%8*@(1+);(+*')(8,%)*&'1+&?+.(81*1)(')+%&''(%)*&'1+=*);+X,0/(Y1+,/0&8*);92
`His experience is confirmed by our experience describedin this paper, and by the experience of one of the
`3*1+(O.(8*('%(+*1+%&'?*89(-+@:+&<8+(O.(8*('%(+-(1%8*@(-+*'+);*1+.,.(8C+,'-+@:+);(+(O.(8*('%(+&?+&'(+&?+);(
`authors with the X Window System, which caused the original introduction ofthe ability to disable Nagle's
`,<);&81+=*);+);(+D+E*'-&=+F:1)(9C+=;*%;+%,<1(-+);(+&8*0*',/+*')8&-<%)*&'+&?+);(+,@*/*):+)&+-*1,@/(+X,0/(Y1
`algorithm into BSD derived TCP implementations.
`,/0&8*);9+*')&+ZF[+-(8*>(-+4L5+*9./(9('),)*&'12
`Simon Spero analyzed HTTP/1.0 performance[6] and prepared a proposal for a replacement for HTTP.
`F*9&'+F.(8&+,',/:N(-+3445672V+.(8?&89,'%(+GJI+,'-+.8(.,8(-+,+.8&.&1,/+?&8+,+8(./,%(9(')+?&8+34452
`HTTP/1.1, however, was constrained to maintain upward compatibility with HTTP/1.0. Manyofhis suggestions
`34456727C+;&=(>(8C+=,1+%&'1)8,*'(-+)&+9,*'),*'+<.=,8-+%&9.,)*@*/*):+=*);+3445672V2+\,':+&?+;*1+1<00(1)*&'1
`are worthwhile and should be explored further.
`,8(+=&8);=;*/(+,'-+1;&</-+@(+(O./&8(-+?<8);(82
`Style sheets have a long history in the Web [30]. We believe that the character of our results will likely be
`F):/(+1;(()1+;,>(+,+/&'0+;*1)&8:+*'+);(+E(@+G]VI2+E(+@(/*(>(+);,)+);(+%;,8,%)(8+&?+&<8+8(1</)1+=*//+/*B(/:+@(
`similar for other style sheet systems. However, we are not awareof any prior work investigating the network
`1*9*/,8+?&8+&);(8+1):/(+1;(()+1:1)(912+3&=(>(8C+=(+,8(+'&)+,=,8(+&?+,':+.8*&8+=&8B+*'>(1)*0,)*'0+);(+'()=&8B
`performance consequencesofstyle sheets.
`.(8?&89,'%(+%&'1(^<('%(1+&?+1):/(+1;(()12
`Test Setup
`_`abcd`bef
`Test Web Site
`_`abcg`hcdib`
`Wesynthesized a test web site serving data by combining data (HTMLand GIF imagedata) from two very
`E(+1:');(1*N(-+,+)(1)+=(@+1*)(+1(8>*'0+-,),+@:+%&9@*'*'0+-,),+Q34\j+,'-+kWl+*9,0(+-,),R+?8&9+)=&+>(8:
`heavily used homepages (Netscape and Microsoft) into one; hereafter called "Microscape". The initial layout of
`;(,>*/:+<1(-+;&9(+.,0(1+QX()1%,.(+,'-+\*%8&1&?)R+*')&+&'(U+;(8(,?)(8+%,//(-+mnopqrsptuvm2+4;(+*'*)*,/+/,:&<)+&?
`the Microscape website was a single page containing typical HTMLtotaling 42KB with 42 inlined GIF images
`);(+\*%8&1%,.(+=(@+1*)(+=,1+,+1*'0/(+.,0(+%&'),*'*'0+):.*%,/+34\j+)&),/*'0+wxyZ+=*);+wx+*'/*'(-+kWl+*9,0(1
`totaling 125KB. The embedded imagesrange in size from 70B to 40KB; most are small, with 19 imagesless
`)&),/*'0+7xHyZ2+4;(+(9@(--(-+*9,0(1+8,'0(+*'+1*N(+?8&9+SVZ+)&+wVyZU+9&1)+,8(+19,//C+=*);+7P+*9,0(1+/(11
`than 1KB, 7 images between 1KB and 2KB,and 6 images between 2KB and 3KB. While the resulting HTML
`);,'+7yZC+S+*9,0(1+@()=(('+7yZ+,'-+xyZC+,'-+J+*9,0(1+@()=(('+xyZ+,'-+]yZ2+E;*/(+);(+8(1</)*'0+34\j
`page is larger, and contains more images than mightbe typical, such pages can be found on the Web.
`.,0(+*1+/,80(8C+,'-+%&'),*'1+9&8(+*9,0(1+);,'+9*0;)+@(+):.*%,/C+1<%;+.,0(1+%,'+@(+?&<'-+&'+);(+E(@2
`
`First Time Retrieval Test
`zi{abc_i|`c}`b{i`~€c_`ab
`The first time retrieval test is equivalent to a browservisiting a site for the first time, e.g. its cache is empty and
`4;(+?*81)+)*9(+8()8*(>,/+)(1)+*1+(^<*>,/(')+)&+,+@8&=1(8+>*1*)*'0+,+1*)(+?&8+);(+?*81)+)*9(C+(202+*)1+%,%;(+*1+(9.):+,'-
`it has to retrieve the top page andall the embedded objects. In HTTP,this is equivalent to 43 GET requests.
`*)+;,1+)&+8()8*(>(+);(+)&.+.,0(+,'-+,//+);(+(9@(--(-+&@(%)12+W'+3445C+);*1+*1+(^<*>,/(')+)&+w]+‚ƒ„+8(^<(1)12
`
`Revalidate Test
`}`~€i…b`c_`ab
`This test is equivalent to revisiting a home page where the contents are already available in a local cache. The
`4;*1+)(1)+*1+(^<*>,/(')+)&+8(>*1*)*'0+,+;&9(+.,0(+=;(8(+);(+%&')(')1+,8(+,/8(,-:+,>,*/,@/(+*'+,+/&%,/+%,%;(2+4;(
`initial page and all embedded objects are validated, resulting in no actual transfer of the HTML or the embedded
`*'*)*,/+.,0(+,'-+,//+(9@(--(-+&@(%)1+,8(+>,/*-,)(-C+8(1</)*'0+*'+'&+,%)<,/+)8,'1?(8+&?+);(+34\j+&8+);(+(9@(--(-
`objects. In HTTP, this is equivalent to 43 Conditional GET requests. HTTP/1.1 supports two mechanismsfor
`&@(%)12+W'+3445C+);*1+*1+(^<*>,/(')+)&+w]+†r‡ˆo‰or‡tŠ(cid:139)‚ƒ„+8(^<(1)12+34456727+1<..&8)1+)=&+9(%;,'*191+?&8
`cache validation: entity tags, which are a guaranteed uniquetag for a particular version of an object, and date
`%,%;(+>,/*-,)*&'Œ+v‡‰o‰(cid:139)‰tŽsC+=;*%;+,8(+,+0<,8,')((-+<'*^<(+),0+?&8+,+.,8)*%</,8+>(81*&'+&?+,'+&@(%)C+,'-+-,)(
`stamps. HTTP/1.0 only supports thelatter.
`1),9.12+3445672V+&'/:+1<..&8)1+);(+/,))(82
`
`https://www.w3.org/Protocols/HTTP/Performance/Pipeline
`
`  
`! 
`
`
`"  
` #"#
`
`Petitioners Ex-] O ] 6, Page 5 of 19
`
`5/19
` $
`
`

`

`   
`
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`
`&''()*+,-./00123-45.-02167898-:;-5<-1=8-692.71<-1>-=7:444-?692.71<-@+*AB-4C7DC-./0012398-0=57<-&''()*+,
`473C-E/=370=9-.7E/=35<91/.-D1<<9D371<.-:93499<-341-0992.-5<8-<1-092.7.39<3-D5DC9+-F<-3C7.-D5.9-49-.7E/=5398-3C9
`D5DC9-65=785371<-:9C56712-:;-7../7<G-&HIA-29J/9.3.-1<-3C9-7E5G9.-7<.3958-1>-KLMNOPOLMQRSTUV-29J/9.3.+-'C9
`021>7=9-1>-3C9-&''()*+,-2965=785371<-29J/9.3.-3C929>129-45.-5-3135=-1>-@W-5..1D75398-473C-3C9-310-05G9-473C-1<9
`TUV-?&'XYB-5<8-@Z-[U\]-29J/9.3.-?7E5G9.B^-7<-3C9-7<7375=-39.3.+-'C9-&''()*+*-7E0=9E9<35371<-1>-=7:444
`?692.71<-_+*B-87>>92.->21E-3C9-&''()*+,-7E0=9E9<35371<+-F3-/.9.-5->/==-&''()*+*-D1E0=75<3-092.7.39<3-D5DC9
`G9<92537<G-@W-KLMNOPOLMQRSTUV-29J/9.3.-473C-50021027539-D5DC9-65=785371<-C95892.-31-E5`9-3C9-39.3-E129-.7E7=52
`31-=7`9=;-:214.92-:9C56712+-'C929>129-3C9-</E:92-1>-05D`93.-7<-3C9-29./=3.-29012398-:9=14->12-&''()*+,-529
`C7GC92-3C5<-1>-3C9-D1229D3-D5DC9-65=785371<-8535-29012398->12-&''()*+*+
`
`abcdefghijklfejmbjcnhobncbp
`
`F<-12892-31-E95./29-3C9-092>12E5<D9-7<-D1EE1<=;-/.98-87>>929<3-<93412`-9<6721<E9<3.^-49-/.98-3C9->1==147<G
`?'5:=9-*B-3C299-D1E:7<5371<.-1>-:5<84783C-5<8-=539<D;q
`
`xoo yzz
`sejjbwclej
`stujjbv
`|-*E. *@},
`&7GC-:5<84783C^-=14-=539<D;YIr-{-*,X:73-H3C92<93
`‚-ƒ,-E.*@},
`&7GC-:5<84783C^-C7GC-=539<D;~Ir-{-XI-?XF')Y€B-31-I-?YYB
`Y14-:5<84783C^-C7GC-=539<D;(((-{-Z„+„`-E189E-=7<9-/.7<G-Y€-875=/0-.9267D9‚-*_,-E.*@},
`'5:=9-*-'9.398-r93412`-H<6721<E9<3.
`
`…††vlwuclejn‡hyuwtljbnhujphˆzn
`
`€96925=-0=53>12E.-4929-/.98-7<-3C9-7<7375=-.35G9-1>-3C9-9‰0927E9<3.->12-2/<<7<G-3C9-&''(-.92692.+-&149692^-49
`9<898-/0-/.7<G-29=53769=;->5.3-E5DC7<9.-31-32;-31-02969<3-/<>129.99<-:133=9<9D`.-7<-3C9-.92692.-5<8-D=79<3.-/.98+
`Š7G.54-7.-427339<-9<3729=;-7<-Š565-5<8--29=79.-1<-.09D7>7D-<93412`->953/29.->12-D1<321==7<G-'(-02167898-1<=;-:;
`-------- ------- --- ---
`Š565-A969=10E9<3-‹73-?ŠA‹B-*+*+-I05DC9-7.-427339<-7<--5<8-2/<.-1<-E/=370=9-ŒrF-65275<3.+
`
`’12DC+4W+12G-^-A7G735=-I=0C5€35371<-@,,-@)ZWW^-ŒrF-@+,5
`
`3/2<+99+=:=+G16^-A7G735=-I=0C5€35371<-W,,,^-ŒrF-@+,
`
`:7G+4W+12G-^-A/5=-(9<37/E-(21-(^-~7<814.-r'-€92692-@+,
`
`Š7G.54-*+,}-5<8-I05DC9-*+Z:*,
`
`o†bhujphbfnlej
`sem†ejbjc
`€92692-&5284529 444Z}+4W+12G^-€/<-€(I‘-Œ=325{*^-€1=527.-Z+_
`YIr-=79<3
`&5284529
`~Ir-=79<3
`&5284529
`(((-=79<3
`&5284529
`&''(-€92692
`€1>34529
`&''(-=79<3
`€1>34529
`
`=7:444-21:13^-r93.D509-1EE/<7D5312-@+,-:935-_-5<8-X7D21.1>3-F<392<93-H‰0=1292-@+,-:935
`*-1<-~7<814.-r'
`'5:=9-Z-{-I00=7D5371<.^-X5DC7<9.^-5<8-Ž€.
`
`r1<9-1>-3C9-E5DC7<9.-4929-/<892-.7G<7>7D5<3-=158-4C7=9-3C9-39.3.-4929-2/<+-'C9-.92692-7.-789<37D5=-3C21/GC-1/2
`>7<5=-39.3.-{-1<=;-3C9-D=79<3-DC5<G9.-D1<<9D37673;-5<8-:9C56712+-13C-Š7G.54-5<8-Y7:444-529-D/229<3=;-5657=5:=9
`473C-&''()*+*-7E0=9E9<35371<.-473C1/3-./00123->12-3C9->953/29.-89.D27:98-7<-3C7.-05092-5<8-I05DC9-7.-7<-:935
`29=95.9+-A/27<G-3C9-9‰0927E9<3.-DC5<G9.-4929-E589-31-5==-3C299-500=7D5371<.+-'C9.9-DC5<G9.-47==-:9-E589
`5657=5:=9-3C21/GC-<12E5=-29=95.9-021D98/29.->12-95DC-1>-3C9-500=7D5371<.+
`
`“jlcluvh“jkbncl”uclejnhujpho•jlj”
`
`'C9-&''()*+,-21:13-45.-.93-31-/.9-0=57<-&''()*+,-29J/9.3.-/.7<G-1<9-'(-D1<<9D371<-092-29J/9.3+-~9-.93-3C9
`E5‰7E/E-</E:92-1>-.7E/=35<91/.-D1<<9D371<.-31-@^-3C9-.5E9-5.-r93.D509-r567G5312–.-89>5/=3-?5<8-C528-47298
`
`  
`! 
`
`
`"  
` #"#
`$ %
`
`

`

`   
`
`
`

(cid:13)
`(cid:13)(cid:13)
`(cid:13) (cid:13)(cid:13)(cid:13)
`
`&'()&*&+,)-,-*./0,1*-23
`
`45-6.,-60-)/7,899:;<3=+,>6,.'/,-?6,.1@1-,'0,',0)&AB6,899:;<3<,CB)6/-,*0)/7,A6.0)0-6/-,C1//6C-)1/03,9?'-,)0+,-?6
`.6D*60-,;,.60A1/06,06D*6/C6,B11E0,)F6/-)C'B,-1,899:;<3=,@*-,'BB,C1&&*/)C'-)1/,?'AA6/0,1/,-?6,0'&6,9G:
`C1//6C-)1/,)/0-6'F,15,H+,?6/C6,06.)'B)I)/7,'BB,.6D*60-03,9?6,.60*B-0,'0,066/,)/,9'@B6,J,>'0,',0)7/)5)C'/-,0'K)/7,)/
`9G:,A'CE6-0,*0)/7,899:;<3<,@*-,'B01,',@)7,)/C.6'06,)/,6B'A06F,-)&63
`
`LMNOPMQMQR
`
`40,',&6'/0,-1,B1>6.,-?6,6B'A06F,-)&6,'/F,)&A.1K6,-?6,655)C)6/CS+,>6,)/-.1F*C6F,A)A6B)/)/7,)/-1,B)@>>>3,9?'-,)0+
`)/0-6'F,15,>')-)/7,1/,',.60A1/06,-1,'..)K6,@651.6,)00*)/7,/6>,.6D*60-0+,'0,&'/S,.6D*60-0,'0,A100)@B6,'.6,)00*6F,'-
`1/C63,9?6,.60A1/060,'.6,0-)BB,06.)'B)I6F,'/F,/1,C?'/760,>6.6,&'F6,-1,-?6,899:,&600'760T,1/BS,-?6,-)&)/7,?'0
`C?'/76F,'0,-?6,.1@1-,?'0,&*B-)AB6,1*-0-'/F)/7,.6D*60-0,1/,-?6,0'&6,C1//6C-)1/3
`
`9?6,.1@1-,76/6.'-60,D*)-6,0&'BB,899:,.6D*60-0,U,1*.,B)@.'.S,)&AB6&6/-'-)1/,)0,K6.S,C'.65*B,/1-,-1,76/6.'-6
`*//6C600'.S,?6'F6.0,'/F,/1-,-1,>'0-6,@S-60,1/,>?)-6,0A'C63,9?6,.60*B-,)0,'/,'K6.'76,.6D*60-,0)I6,15,'.1*/F,<V=
`@S-60+,>?)C?,)0,0)7/)5)C'/-BS,0&'BB6.,-?'/,&'/S,6()0-)/7,A.1F*C-,899:,)&AB6&6/-'-)1/0+,'0,066/,)/,9'@B6,<=,'/F
`9'@B6,<<,@6B1>3
`
`9?6,.6D*60-0,'.6,@*556.6F,@651.6,-.'/0&)00)1/,01,-?'-,&*B-)AB6,899:,.6D*60-0,C'/,@6,06/-,>)-?,-?6,0'&6,9G:
`067&6/-3,9?)0,?'0,',0)7/)5)C'/-,)&A'C-,1/,-?6,/*&@6.,15,A'CE6-0,.6D*).6F,-1,-.'/0&)-,-?6,A'SB1'F,'/F,B1>6.0
`0S0-6&,-)&6,G:W,*0'76,@S,@1-?,CB)6/-,'/F,06.K6.3,81>6K6.+,-?)0,&6'/0,-?'-,.6D*60-0,'.6,/1-,)&&6F)'-6BS
`-.'/0&)--6F+,'/F,>6,-?6.651.6,/66F,',&6C?'/)0&,-1,5B*0?,-?6,1*-A*-,@*556.3,X).0-,>6,)&AB6&6/-6F,',K6.0)1/,>)-?
`->1,&6C?'/)0&0Y
`
`<3,9?6,@*556.,>'0,5B*0?6F,)5,-?6,F'-',)/,-?6,1*-A*-,@*556.,.6'C?6F,',C6.-')/,0)I63,Z6,6(A6.)&6/-6F,>)-?,-?6
`1*-A*-,@*556.,0)I6,'/F,51*/F,-?'-,<=[H,@S-60,)0,',711F,C1&A.1&)063,\/,C'06,-?6,]9W,)0,^J_,1.,^<[,>6,>)BB
`A.1F*C6,->1,5*BB,9G:,067&6/-0+,'/F,)5,-?6,]9W,)0,<H_=,`a-?6./6-,0)I62,-?6/,>6,C'/,/)C6BS,5)-,)/-1,1/6
`067&6/-3
`[3,Z6,)/-.1F*C6F,',-)&6.,)/,-?6,1*-A*-,@*556.,0-.6'&,>?)C?,>1*BF,-)&6U1*-,'5-6.,',0A6C)5)6F,A6.)1F,15,-)&6
`'/F,51.C6,-?6,@*556.,-1,@6,5B*0?6F3,\-,)0,/1-,CB6'.,>?'-,-?6,1A-)&'B,5B*0?,-)&6U1*-,A6.)1F,)0,@*-,)-,)0,B)E6BS
`-?'-,)-,)0,',5*/C-)1/,15,-?6,/6->1.E,B1'F,'/F,C1//6C-)K)-S3,\/)-)'BBS,>6,*06F,',<,06C1/F,F6B'S,51.,-?6,)/)-)'B
`.60*B-0,)/,9'@B6,J+,@*-,*06F,',^=,&0,F6B'S,)/,51.,'BB,B'-6.,-60-03,X*.-?6.,>1.E,)0,.6D*).6F,-1,*/F6.0-'/F
`>?6.6,>6,0?1*BF,06-,0*C?,',-)&6.+,>?)C?,&)7?-,'B01,-'E6,)/-1,'CC1*/-,-?6,b99,51.,-?)0,A'.-)C*B'.
`C1//6C-)1/,1.,1-?6.,5'C-1.0+,-1,0*AA1.-,1BF,CB)6/-0,>?)C?,F1,/1-,6(AB)C)-BS,5B*0?,-?6,@*556.3
`
`899:;<3=899:;<3<,:6.0)0-6/-899:;<3<,:)A6B)/6
`,
`_
`<
`<
`]'(,0)&*B-'/61*0,01CE6-0
`91-'B,/*&@6.,15,01CE6-0,*06F H=
`<
`<
`:'CE6-0,5.1&,CB)6/-,-1,06.K6. [[_
`f=
`[^
`:'CE6-0,5.1&,06.K6.,-1,CB)6/- [f<
`<^J
`^g
`91-'B,/*&@6.,15,A'CE6-0
`HVf
`[[J
`gJ
`91-'B,6B'A06F,-)&6,h06C0i
`<3g^
`H3<J
`J3=[
`9'@B6,J,U,c)70'>,U,\/)-)'B,8)7?,d'/F>)F-?+,e1>,e'-6/CS,G'C?6,b6K'B)F'-)1/
`960-
`
`Z6,>6.6,0)&*B-'/61*0BS,K6.S,?'AAS,'/F,D*)-6,F)0'AA1)/-6F,>)-?,-?6,)/)-)'B,.60*B-0,'@1K6+,-'E6/,B'-6,'-,/)7?-,1/,'
`D*)6-,a-?6./6-3,aB'A06F,-)&6,A6.51.&'/C6,15,899:;<3<,>)-?,A)A6B)/)/7,>'0,>1.06,-?'/,899:;<3=,)/,-?)0,)/)-)'B
`)&AB6&6/-'-)1/+,-?1*7?,-?6,/*&@6.,15,A'CE6-0,*06F,>6.6,F.'&'-)C'BBS,@6--6.3,Z6,0C.'-C?6F,1*.,?6'F0,51.,',F'S+
`-?6/,C1/K)/C6F,1*.06BK60,-?'-,1/,',B1C'B,a-?6./6-+,-?6.6,>'0,/1,.6'01/,-?'-,899:;<3<,0?1*BF,6K6.,A6.51.&,&1.6
`0B1>BS,-?'/,899:;<3=3,9?6,B1C'B,a-?6./6-,C'//1-,0*556.,5.1&,5')./600,A.1@B6&0,-?'-,&)7?-,7)K6,&*B-)AB6
`C1//6C-)1/0,',A6.51.&'/C6,6F76,)/,',B1/7,?'*B,/6->1.E3,Z6,F*