HTTP/3 鏉ヤ簡 !

Posted 2021-04-26 寮€鍙戣€呮妧鏈墠绾?/a>

鐐瑰嚮鈥?/span>寮€鍙戣€呮妧鏈墠绾?/span>鈥濓紝閫夋嫨鈥滄槦鏍囸煍濃€?/span>

鍦ㄧ湅|鏄熸爣|鐣欒█,  鐪熺埍

浣滆€咃細billpchen锛岃吘璁湅鐐瑰墠绔紑鍙戝伐绋嬪笀

2015 骞?HTTP/2 鏍囧噯鍙戣〃鍚庯紝澶у鏁颁富娴佹祻瑙堝櫒涔熶簬褰撳勾骞村簳鏀寔璇ユ爣鍑嗐€傛鍚庯紝鍑€熺潃澶氳矾澶嶇敤銆佸ご閮ㄥ帇缂┿€佹湇鍔″櫒鎺ㄩ€佺瓑浼樺娍锛孒TTP/2 寰楀埌浜嗚秺鏉ヨ秺澶氬紑鍙戣€呯殑闈掔潗锛屼笉鐭ヤ笉瑙夌殑 HTTP 宸茬粡鍙戝睍鍒颁簡绗笁浠ｃ€傛湰鏂囧熀浜庡叴瓒ｉ儴钀芥帴鍏?HTTP/3 鐨勫疄璺碉紝鑱婁竴鑱?HTTP/3 鐨勫師鐞嗕互鍙婁笟鍔℃帴鍏ョ殑鏂瑰紡銆?/strong>

1. HTTP/3 鍘熺悊

1.1 HTTP 鍘嗗彶

鍦ㄤ粙缁?HTTP/3 涔嬪墠锛屾垜浠厛绠€鍗曠湅涓?HTTP 鐨勫巻鍙诧紝浜嗚В涓?HTTP/3 鍑虹幇鐨勮儗鏅€?/span>

闅忕潃缃戠粶鎶€鏈殑鍙戝睍锛?999 骞磋璁＄殑 HTTP/1.1 宸茬粡涓嶈兘婊¤冻闇€姹傦紝鎵€浠?Google 鍦?2009 骞磋璁′簡鍩轰簬 TCP 鐨?SPDY锛屽悗鏉?SPDY 鐨勫紑鍙戠粍鎺ㄥ姩 SPDY 鎴愪负姝ｅ紡鏍囧噯锛屼笉杩囨渶缁堟病鑳介€氳繃銆備笉杩?SPDY 鐨勫紑鍙戠粍鍏ㄧ▼鍙備笌浜?HTTP/2 鐨勫埗瀹氳繃绋嬶紝鍙傝€冧簡 SPDY 鐨勫緢澶氳璁★紝鎵€浠ユ垜浠竴鑸涓?SPDY 灏辨槸 HTTP/2 鐨勫墠韬€傛棤璁?SPDY 杩樻槸 HTTP/2锛岄兘鏄熀浜?TCP 鐨勶紝TCP 涓?UDP 鐩告瘮鏁堢巼涓婂瓨鍦ㄥぉ鐒剁殑鍔ｅ娍锛屾墍浠?2013 骞?Google 寮€鍙戜簡鍩轰簬 UDP 鐨勫悕涓?QUIC 鐨勪紶杈撳眰鍗忚锛孮UIC 鍏ㄧО Quick UDP Internet Connections锛屽笇鏈涘畠鑳芥浛浠?TCP锛屼娇寰楃綉椤典紶杈撴洿鍔犻珮鏁堛€傚悗缁忔彁璁紝浜掕仈缃戝伐绋嬩换鍔＄粍姝ｅ紡灏嗗熀浜?QUIC 鍗忚鐨?HTTP 锛圚TTP over QUIC锛夐噸鍛藉悕涓?HTTP/3銆?/span>

1.2 QUIC 鍗忚姒傝

TCP 涓€鐩存槸浼犺緭灞備腑涓捐冻杞婚噸鐨勫崗璁紝鑰?UDP 鍒欓粯榛樻棤闂伙紝鍦ㄩ潰璇曚腑闂埌 TCP 鍜?UDP 鐨勫尯鍒椂锛屾湁鍏?UDP 鐨勫洖绛斿父甯稿瀵ュ嚑璇紝闀挎湡浠ユ潵 UDP 缁欎汉鐨勫嵃璞″氨鏄竴涓緢蹇絾涓嶅彲闈犵殑浼犺緭灞傚崗璁€備絾鏈夋椂鍊欎粠鍙︿竴涓搴︾湅锛岀己鐐瑰彲鑳戒篃鏄紭鐐广€俀UIC锛圦uick UDP Internet Connections锛屽揩閫?UDP 缃戠粶杩炴帴锛?鍩轰簬 UDP锛屾鏄湅涓簡 UDP 鐨勯€熷害涓庢晥鐜囥€傚悓鏃?QUIC 涔熸暣鍚堜簡 TCP銆乀LS 鍜?HTTP/2 鐨勪紭鐐癸紝骞跺姞浠ヤ紭鍖栥€傜敤涓€寮犲浘鍙互娓呮櫚鍦拌〃绀轰粬浠箣闂寸殑鍏崇郴銆?/span>

閭?QUIC 鍜?HTTP/3 浠€涔堝叧绯诲憿锛烸UIC 鏄敤鏉ユ浛浠?TCP銆丼SL/TLS 鐨勪紶杈撳眰鍗忚锛屽湪浼犺緭灞備箣涓婅繕鏈夊簲鐢ㄥ眰锛屾垜浠啛鐭ョ殑搴旂敤灞傚崗璁湁 HTTP銆丗TP銆両MAP 绛夛紝杩欎簺鍗忚鐞嗚涓婇兘鍙互杩愯鍦?QUIC 涔嬩笂锛屽叾涓繍琛屽湪 QUIC 涔嬩笂鐨?HTTP 鍗忚琚О涓?HTTP/3锛岃繖灏辨槸鈥滺TTP over QUIC 鍗?HTTP/3鈥滅殑鍚箟銆?/span>

鍥犳鎯宠浜嗚В HTTP/3锛孮UIC 鏄粫涓嶈繃鍘荤殑锛屼笅闈富瑕侀€氳繃鍑犱釜閲嶈鐨勭壒鎬ц澶у瀵?QUIC 鏈夋洿娣辩殑鐞嗚В銆?/span>

1.3 闆?RTT 寤虹珛杩炴帴

鐢ㄤ竴寮犲浘鍙互褰㈣薄鍦扮湅鍑?HTTP/2 鍜?HTTP/3 寤虹珛杩炴帴鐨勫樊鍒€?/span>

HTTP/2 鐨勮繛鎺ラ渶瑕?3 RTT锛屽鏋滆€冭檻浼氳瘽澶嶇敤锛屽嵆鎶婄涓€娆℃彙鎵嬬畻鍑烘潵鐨勫绉板瘑閽ョ紦瀛樿捣鏉ワ紝閭ｄ箞涔熼渶瑕?2 RTT锛屾洿杩涗竴姝ョ殑锛屽鏋?TLS 鍗囩骇鍒?1.3锛岄偅涔?HTTP/2 杩炴帴闇€瑕?2 RTT锛岃€冭檻浼氳瘽澶嶇敤鍒欓渶瑕?1 RTT銆傛湁浜轰細璇?HTTP/2 涓嶄竴瀹氶渶瑕?HTTPS锛屾彙鎵嬭繃绋嬭繕鍙互绠€鍖栥€傝繖娌℃瘺鐥咃紝HTTP/2 鐨勬爣鍑嗙殑纭笉闇€瑕佸熀浜?HTTPS锛屼絾瀹為檯涓婃墍鏈夋祻瑙堝櫒鐨勫疄鐜伴兘瑕佹眰 HTTP/2 蹇呴』鍩轰簬 HTTPS锛屾墍浠?HTTP/2 鐨勫姞瀵嗚繛鎺ュ繀涓嶅彲灏戙€傝€?HTTP/3 棣栨杩炴帴鍙渶瑕?1 RTT锛屽悗闈㈢殑杩炴帴鏇存槸鍙渶 0 RTT锛屾剰鍛崇潃瀹㈡埛绔彂缁欐湇鍔＄鐨勭涓€涓寘灏卞甫鏈夎姹傛暟鎹紝杩欎竴鐐?HTTP/2 闅句互鏈涘叾椤硅儗銆傞偅杩欒儗鍚庢槸浠€涔堝師鐞嗗憿锛熸垜浠叿浣撶湅涓?QUIC 鐨勮繛鎺ヨ繃绋嬨€?/span>

Step1锛氶娆¤繛鎺ユ椂锛屽鎴风鍙戦€?Inchoate Client Hello 缁欐湇鍔＄锛岀敤浜庤姹傝繛鎺ワ紱

Step2锛氭湇鍔＄鐢熸垚 g銆乸銆乤锛屾牴鎹?g銆乸 鍜?a 绠楀嚭 A锛岀劧鍚庡皢 g銆乸銆丄 鏀惧埌 Server Config 涓啀鍙戦€?Rejection 娑堟伅缁欏鎴风锛?/span>

Step3锛氬鎴风鎺ユ敹鍒?g銆乸銆丄 鍚庯紝鑷繁鍐嶇敓鎴?b锛屾牴鎹?g銆乸銆乥 绠楀嚭 B锛屾牴鎹?A銆乸銆乥 绠楀嚭鍒濆瀵嗛挜 K銆侭 鍜?K 绠楀ソ鍚庯紝瀹㈡埛绔細鐢?K 鍔犲瘑 HTTP 鏁版嵁锛岃繛鍚?B 涓€璧峰彂閫佺粰鏈嶅姟绔紱

Step4锛氭湇鍔＄鎺ユ敹鍒?B 鍚庯紝鏍规嵁 a銆乸銆丅 鐢熸垚涓庡鎴风鍚屾牱鐨勫瘑閽ワ紝鍐嶇敤杩欏瘑閽ヨВ瀵嗘敹鍒扮殑 HTTP 鏁版嵁銆備负浜嗚繘涓€姝ョ殑瀹夊叏锛堝墠鍚戝畨鍏ㄦ€э級锛屾湇鍔＄浼氭洿鏂拌嚜宸辩殑闅忔満鏁?a 鍜屽叕閽ワ紝鍐嶇敓鎴愭柊鐨勫瘑閽?S锛岀劧鍚庢妸鍏挜閫氳繃 Server Hello 鍙戦€佺粰瀹㈡埛绔€傝繛鍚?Server Hello 娑堟伅锛岃繕鏈?HTTP 杩斿洖鏁版嵁锛?/span>

Step5锛氬鎴风鏀跺埌 Server Hello 鍚庯紝鐢熸垚涓庢湇鍔＄涓€鑷寸殑鏂板瘑閽?S锛屽悗闈㈢殑浼犺緭閮戒娇鐢?S 鍔犲瘑銆?/span>

杩欐牱锛孮UIC 浠庤姹傝繛鎺ュ埌姝ｅ紡鎺ュ彂 HTTP 鏁版嵁涓€鍏辫姳浜?1 RTT锛岃繖 1 涓?RTT 涓昏鏄负浜嗚幏鍙?Server Config锛屽悗闈㈢殑杩炴帴濡傛灉瀹㈡埛绔紦瀛樹簡 Server Config锛岄偅涔堝氨鍙互鐩存帴鍙戦€?HTTP 鏁版嵁锛屽疄鐜?0 RTT 寤虹珛杩炴帴銆?/span>

杩欓噷浣跨敤鐨勬槸 DH 瀵嗛挜浜ゆ崲绠楁硶锛孌H 绠楁硶鐨勬牳蹇冨氨鏄湇鍔＄鐢熸垚 a銆乬銆乸 3 涓殢鏈烘暟锛宎 鑷繁鎸佹湁锛実 鍜?p 瑕佷紶杈撶粰瀹㈡埛绔紝鑰屽鎴风浼氱敓鎴?b 杩?1 涓殢鏈烘暟锛岄€氳繃 DH 绠楁硶瀹㈡埛绔拰鏈嶅姟绔彲浠ョ畻鍑哄悓鏍风殑瀵嗛挜銆傚湪杩欒繃绋嬩腑 a 鍜?b 骞朵笉鍙備笌缃戠粶浼犺緭锛屽畨鍏ㄦ€уぇ澶ф彁楂樸€傚洜涓?p 鍜?g 鏄ぇ鏁帮紝鎵€浠ュ嵆浣垮湪缃戠粶涓紶杈撶殑 p銆乬銆丄銆丅 閮借鍔寔锛岄偅涔堥潬鐜板湪鐨勮绠楁満绠楀姏涔熸病娉曠牬瑙ｅ瘑閽ャ€?/span>

1.4 杩炴帴杩佺Щ

TCP 杩炴帴鍩轰簬鍥涘厓缁勶紙婧?IP銆佹簮绔彛銆佺洰鐨?IP銆佺洰鐨勭鍙ｏ級锛屽垏鎹㈢綉缁滄椂鑷冲皯浼氭湁涓€涓洜绱犲彂鐢熷彉鍖栵紝瀵艰嚧杩炴帴鍙戠敓鍙樺寲銆傚綋杩炴帴鍙戠敓鍙樺寲鏃讹紝濡傛灉杩樹娇鐢ㄥ師鏉ョ殑 TCP 杩炴帴锛屽垯浼氬鑷磋繛鎺ュけ璐ワ紝灏卞緱绛夊師鏉ョ殑杩炴帴瓒呮椂鍚庨噸鏂板缓绔嬭繛鎺ワ紝鎵€浠ユ垜浠湁鏃跺€欏彂鐜板垏鎹㈠埌涓€涓柊缃戠粶鏃讹紝鍗充娇鏂扮綉缁滅姸鍐佃壇濂斤紝浣嗗唴瀹硅繕鏄渶瑕佸姞杞藉緢涔呫€傚鏋滃疄鐜板緱濂斤紝褰撴娴嬪埌缃戠粶鍙樺寲鏃剁珛鍒诲缓绔嬫柊鐨?TCP 杩炴帴锛屽嵆浣胯繖鏍凤紝寤虹珛鏂扮殑杩炴帴杩樻槸闇€瑕佸嚑鐧炬绉掔殑鏃堕棿銆?/span>

QUIC 鐨勮繛鎺ヤ笉鍙楀洓鍏冪粍鐨勫奖鍝嶏紝褰撹繖鍥涗釜鍏冪礌鍙戠敓鍙樺寲鏃讹紝鍘熻繛鎺ヤ緷鐒剁淮鎸併€傞偅杩欐槸鎬庝箞鍋氬埌鐨勫憿锛熼亾鐞嗗緢绠€鍗曪紝QUIC 杩炴帴涓嶄互鍥涘厓缁勪綔涓烘爣璇嗭紝鑰屾槸浣跨敤涓€涓?64 浣嶇殑闅忔満鏁帮紝杩欎釜闅忔満鏁拌绉颁负 Connection ID锛屽嵆浣?IP 鎴栬€呯鍙ｅ彂鐢熷彉鍖栵紝鍙 Connection ID 娌℃湁鍙樺寲锛岄偅涔堣繛鎺ヤ緷鐒跺彲浠ョ淮鎸併€?/span>

1.5 闃熷ご闃诲/澶氳矾澶嶇敤

HTTP/1.1 鍜?HTTP/2 閮藉瓨鍦ㄩ槦澶撮樆濉為棶棰橈紙Head of line blocking锛夛紝閭ｄ粈涔堟槸闃熷ご闃诲鍛紵

TCP 鏄釜闈㈠悜杩炴帴鐨勫崗璁紝鍗冲彂閫佽姹傚悗闇€瑕佹敹鍒?ACK 娑堟伅锛屼互纭瀵规柟宸叉帴鏀跺埌鏁版嵁銆傚鏋滄瘡娆¤姹傞兘瑕佸湪鏀跺埌涓婃璇锋眰鐨?ACK 娑堟伅鍚庡啀璇锋眰锛岄偅涔堟晥鐜囨棤鐤戝緢浣庛€傚悗鏉?HTTP/1.1 鎻愬嚭浜?Pipelining 鎶€鏈紝鍏佽涓€涓?TCP 杩炴帴鍚屾椂鍙戦€佸涓姹傦紝杩欐牱灏卞ぇ澶ф彁鍗囦簡浼犺緭鏁堢巼銆?/span>

鍦ㄨ繖涓儗鏅笅锛屼笅闈㈠氨鏉ヨ皥 HTTP/1.1 鐨勯槦澶撮樆濉炪€備笅鍥句腑锛屼竴涓?TCP 杩炴帴鍚屾椂浼犺緭 10 涓姹傦紝鍏朵腑绗?1銆?銆? 涓姹傚凡琚鎴风鎺ユ敹锛屼絾绗?4 涓姹備涪澶憋紝閭ｄ箞鍚庨潰绗?5 - 10 涓姹傞兘琚樆濉烇紝闇€瑕佺瓑绗?4 涓姹傚鐞嗗畬姣曟墠鑳借澶勭悊锛岃繖鏍峰氨娴垂浜嗗甫瀹借祫婧愩€?/span>

鍥犳锛孒TTP 涓€鑸張鍏佽姣忎釜涓绘満寤虹珛 6 涓?TCP 杩炴帴锛岃繖鏍峰彲浠ユ洿鍔犲厖鍒嗗湴鍒╃敤甯﹀璧勬簮锛屼絾姣忎釜杩炴帴涓槦澶撮樆濉炵殑闂杩樻槸瀛樺湪銆?/span>

HTTP/2 鐨勫璺鐢ㄨВ鍐充簡涓婅堪鐨勯槦澶撮樆濉為棶棰樸€備笉鍍?HTTP/1.1 涓彧鏈変笂涓€涓姹傜殑鎵€鏈夋暟鎹寘琚紶杈撳畬姣曚笅涓€涓姹傜殑鏁版嵁鍖呮墠鍙互琚紶杈擄紝HTTP/2 涓瘡涓姹傞兘琚媶鍒嗘垚澶氫釜 Frame 閫氳繃涓€鏉?TCP 杩炴帴鍚屾椂琚紶杈擄紝杩欐牱鍗充娇涓€涓姹傝闃诲锛屼篃涓嶄細褰卞搷鍏朵粬鐨勮姹傘€傚涓嬪浘鎵€绀猴紝涓嶅悓棰滆壊浠ｈ〃涓嶅悓鐨勮姹傦紝鐩稿悓棰滆壊鐨勮壊鍧椾唬琛ㄨ姹傝鍒囧垎鐨?Frame銆?/span>

浜嬫儏杩樻病瀹岋紝HTTP/2 铏界劧鍙互瑙ｅ喅鈥滆姹傗€濊繖涓矑搴︾殑闃诲锛屼絾 HTTP/2 鐨勫熀纭€ TCP 鍗忚鏈韩鍗翠篃瀛樺湪鐫€闃熷ご闃诲鐨勯棶棰樸€侶TTP/2 鐨勬瘡涓姹傞兘浼氳鎷嗗垎鎴愬涓?Frame锛屼笉鍚岃姹傜殑 Frame 缁勫悎鎴?Stream锛孲tream 鏄?TCP 涓婄殑閫昏緫浼犺緭鍗曞厓锛岃繖鏍?HTTP/2 灏辫揪鍒颁簡涓€鏉¤繛鎺ュ悓鏃跺彂閫佸鏉¤姹傜殑鐩爣锛岃繖灏辨槸澶氳矾澶嶇敤鐨勫師鐞嗐€傛垜浠湅涓€涓緥瀛愶紝鍦ㄤ竴鏉?TCP 杩炴帴涓婂悓鏃跺彂閫?4 涓?Stream锛屽叾涓?Stream1 宸叉纭€佽揪锛孲tream2 涓殑绗?3 涓?Frame 涓㈠け锛孴CP 澶勭悊鏁版嵁鏃舵湁涓ユ牸鐨勫墠鍚庨『搴忥紝鍏堝彂閫佺殑 Frame 瑕佸厛琚鐞嗭紝杩欐牱灏变細瑕佹眰鍙戦€佹柟閲嶆柊鍙戦€佺 3 涓?Frame锛孲tream3 鍜?Stream4 铏界劧宸插埌杈句絾鍗翠笉鑳借澶勭悊锛岄偅涔堣繖鏃舵暣鏉¤繛鎺ラ兘琚樆濉炪€?/span>

涓嶄粎濡傛锛岀敱浜?HTTP/2 蹇呴』浣跨敤 HTTPS锛岃€?HTTPS 浣跨敤鐨?TLS 鍗忚涔熷瓨鍦ㄩ槦澶撮樆濉為棶棰樸€俆LS 鍩轰簬 Record 缁勭粐鏁版嵁锛屽皢涓€鍫嗘暟鎹斁鍦ㄤ竴璧凤紙鍗充竴涓?Record锛夊姞瀵嗭紝鍔犲瘑瀹屽悗鍙堟媶鍒嗘垚澶氫釜 TCP 鍖呬紶杈撱€備竴鑸瘡涓?Record 16K锛屽寘鍚?12 涓?TCP 鍖咃紝杩欐牱濡傛灉 12 涓?TCP 鍖呬腑鏈変换浣曚竴涓寘涓㈠け锛岄偅涔堟暣涓?Record 閮芥棤娉曡В瀵嗐€?/span>

闃熷ご闃诲浼氬鑷?HTTP/2 鍦ㄦ洿瀹规槗涓㈠寘鐨勫急缃戠粶鐜涓嬫瘮 HTTP/1.1 鏇存參锛?/span>

閭?QUIC 鏄浣曡В鍐抽槦澶撮樆濉為棶棰樼殑鍛紵涓昏鏈変袱鐐广€?/span>

• QUIC 鐨勪紶杈撳崟鍏冩槸 Packet锛屽姞瀵嗗崟鍏冧篃鏄?Packet锛屾暣涓姞瀵嗐€佷紶杈撱€佽В瀵嗛兘鍩轰簬 Packet锛岃繖鏍峰氨鑳介伩鍏?TLS 鐨勯槦澶撮樆濉為棶棰橈紱
• QUIC 鍩轰簬 UDP锛孶DP 鐨勬暟鎹寘鍦ㄦ帴鏀剁娌℃湁澶勭悊椤哄簭锛屽嵆浣夸腑闂翠涪澶变竴涓寘锛屼篃涓嶄細闃诲鏁存潯杩炴帴锛屽叾浠栫殑璧勬簮浼氳姝ｅ父澶勭悊銆?/span>

1.6 鎷ュ鎺у埗

鎷ュ鎺у埗鐨勭洰鐨勬槸閬垮厤杩囧鐨勬暟鎹竴涓嬪瓙娑屽叆缃戠粶锛屽鑷寸綉缁滆秴鍑烘渶澶ц礋鑽枫€俀UIC 鐨勬嫢濉炴帶鍒朵笌 TCP 绫讳技锛屽苟鍦ㄦ鍩虹涓婂仛浜嗘敼杩涖€傛墍浠ユ垜浠厛绠€鍗曚粙缁嶄笅 TCP 鐨勬嫢濉炴帶鍒躲€?/span>

TCP 鎷ュ鎺у埗鐢?4 涓牳蹇冪畻娉曠粍鎴愶細鎱㈠惎鍔ㄣ€佹嫢濉為伩鍏嶃€佸揩閫熼噸浼犲拰蹇€熸仮澶嶏紝鐞嗚В浜嗚繖 4 涓畻娉曪紝瀵?TCP 鐨勬嫢濉炴帶鍒朵篃灏辨湁浜嗗ぇ姒備簡瑙ｃ€?/span>

• 鎱㈠惎鍔細鍙戦€佹柟鍚戞帴鏀舵柟鍙戦€?1 涓崟浣嶇殑鏁版嵁锛屾敹鍒板鏂圭‘璁ゅ悗浼氬彂閫?2 涓崟浣嶇殑鏁版嵁锛岀劧鍚庝緷娆℃槸 4 涓€? 涓€︹€﹀憟鎸囨暟绾у闀匡紝杩欎釜杩囩▼灏辨槸鍦ㄤ笉鏂瘯鎺㈢綉缁滅殑鎷ュ绋嬪害锛岃秴鍑洪槇鍊煎垯浼氬鑷寸綉缁滄嫢濉烇紱
• 鎷ュ閬垮厤锛氭寚鏁板闀夸笉鍙兘鏄棤闄愮殑锛屽埌杈炬煇涓檺鍒讹紙鎱㈠惎鍔ㄩ槇鍊硷級涔嬪悗锛屾寚鏁板闀垮彉涓虹嚎鎬у闀匡紱
• 蹇€熼噸浼狅細鍙戦€佹柟姣忎竴娆″彂閫佹椂閮戒細璁剧疆涓€涓秴鏃惰鏃跺櫒锛岃秴鏃跺悗鍗宠涓轰涪澶憋紝闇€瑕侀噸鍙戯紱
• 蹇€熸仮澶嶏細鍦ㄤ笂闈㈠揩閫熼噸浼犵殑鍩虹涓婏紝鍙戦€佹柟閲嶆柊鍙戦€佹暟鎹椂锛屼篃浼氬惎鍔ㄤ竴涓秴鏃跺畾鏃跺櫒锛屽鏋滄敹鍒扮‘璁ゆ秷鎭垯杩涘叆鎷ュ閬垮厤闃舵锛屽鏋滀粛鐒惰秴鏃讹紝鍒欏洖鍒版參鍚姩闃舵銆?/span>

QUIC 閲嶆柊瀹炵幇浜?TCP 鍗忚鐨?Cubic 绠楁硶杩涜鎷ュ鎺у埗锛屽苟鍦ㄦ鍩虹涓婂仛浜嗕笉灏戞敼杩涖€備笅闈粙缁嶄竴浜?QUIC 鏀硅繘鐨勬嫢濉炴帶鍒剁殑鐗规€с€?/span>

1.6.1 鐑彃鎷?/span>

TCP 涓鏋滆淇敼鎷ュ鎺у埗绛栫暐锛岄渶瑕佸湪绯荤粺灞傞潰杩涜鎿嶄綔銆俀UIC 淇敼鎷ュ鎺у埗绛栫暐鍙渶瑕佸湪搴旂敤灞傛搷浣滐紝骞朵笖 QUIC 浼氭牴鎹笉鍚岀殑缃戠粶鐜銆佺敤鎴锋潵鍔ㄦ€侀€夋嫨鎷ュ鎺у埗绠楁硶銆?/span>

1.6.2 鍓嶅悜绾犻敊 FEC

QUIC 浣跨敤鍓嶅悜绾犻敊(FEC锛孎orward Error Correction)鎶€鏈鍔犲崗璁殑瀹归敊鎬с€備竴娈垫暟鎹鍒囧垎涓?10 涓寘鍚庯紝渚濇瀵规瘡涓寘杩涜寮傛垨杩愮畻锛岃繍绠楃粨鏋滀細浣滀负 FEC 鍖呬笌鏁版嵁鍖呬竴璧疯浼犺緭锛屽鏋滀笉骞稿湪浼犺緭杩囩▼涓湁涓€涓暟鎹寘涓㈠け锛岄偅涔堝氨鍙互鏍规嵁鍓╀綑 9 涓寘浠ュ強 FEC 鍖呮帹绠楀嚭涓㈠け鐨勯偅涓寘鐨勬暟鎹紝杩欐牱灏卞ぇ澶у鍔犱簡鍗忚鐨勫閿欐€с€?/span>

杩欐槸绗﹀悎鐜伴樁娈电綉缁滄妧鏈殑涓€绉嶆柟妗堬紝鐜伴樁娈靛甫瀹藉凡缁忎笉鏄綉缁滀紶杈撶殑鐡堕锛屽線杩旀椂闂存墠鏄紝鎵€浠ユ柊鐨勭綉缁滀紶杈撳崗璁彲浠ラ€傚綋澧炲姞鏁版嵁鍐椾綑锛屽噺灏戦噸浼犳搷浣溿€?/span>

1.6.3 鍗曡皟閫掑鐨?Packet Number

TCP 涓轰簡淇濊瘉鍙潬鎬э紝浣跨敤 Sequence Number 鍜?ACK 鏉ョ‘璁ゆ秷鎭槸鍚︽湁搴忓埌杈撅紝浣嗚繖鏍风殑璁捐瀛樺湪缂洪櫡銆?/span>

瓒呮椂鍙戠敓鍚庡鎴风鍙戣捣閲嶄紶锛屽悗鏉ユ帴鏀跺埌浜?ACK 纭娑堟伅锛屼絾鍥犱负鍘熷璇锋眰鍜岄噸浼犺姹傛帴鏀跺埌鐨?ACK 娑堟伅涓€鏍凤紝鎵€浠ュ鎴风灏遍儊闂蜂簡锛屼笉鐭ラ亾杩欎釜 ACK 瀵瑰簲鐨勬槸鍘熷璇锋眰杩樻槸閲嶄紶璇锋眰銆傚鏋滃鎴风璁や负鏄師濮嬭姹傜殑 ACK锛屼絾瀹為檯涓婃槸宸﹀浘鐨勬儏褰紝鍒欒绠楃殑閲囨牱 RTT 鍋忓ぇ锛涘鏋滃鎴风璁や负鏄噸浼犺姹傜殑 ACK锛屼絾瀹為檯涓婃槸鍙冲浘鐨勬儏褰紝鍙堜細瀵艰嚧閲囨牱 RTT 鍋忓皬銆傚浘涓湁鍑犱釜鏈锛孯TO 鏄寚瓒呮椂閲嶄紶鏃堕棿锛圧etransmission TimeOut锛夛紝璺熸垜浠啛鎮夌殑 RTT锛圧ound Trip Time锛屽線杩旀椂闂达級寰堥暱寰楀緢鍍忋€傞噰鏍?RTT 浼氬奖鍝?RTO 璁＄畻锛岃秴鏃舵椂闂寸殑鍑嗙‘鎶婃彙寰堥噸瑕侊紝闀夸簡鐭簡閮戒笉鍚堥€傘€?/span>

QUIC 瑙ｅ喅浜嗕笂闈㈢殑姝т箟闂銆備笌 Sequence Number 涓嶅悓鐨勬槸锛孭acket Number 涓ユ牸鍗曡皟閫掑锛屽鏋?Packet N 涓㈠け浜嗭紝閭ｄ箞閲嶄紶鏃?Packet 鐨勬爣璇嗕笉浼氭槸 N锛岃€屾槸姣?N 澶х殑鏁板瓧锛屾瘮濡?N + M锛岃繖鏍峰彂閫佹柟鎺ユ敹鍒扮‘璁ゆ秷鎭椂灏辫兘鏂逛究鍦扮煡閬?ACK 瀵瑰簲鐨勬槸鍘熷璇锋眰杩樻槸閲嶄紶璇锋眰銆?/span>

1.6.4 ACK Delay

TCP 璁＄畻 RTT 鏃舵病鏈夎€冭檻鎺ユ敹鏂规帴鏀跺埌鏁版嵁鍒板彂閫佺‘璁ゆ秷鎭箣闂寸殑寤惰繜锛屽涓嬪浘鎵€绀猴紝杩欐寤惰繜鍗?ACK Delay銆俀UIC 鑰冭檻浜嗚繖娈靛欢杩燂紝浣垮緱 RTT 鐨勮绠楁洿鍔犲噯纭€?/span>

1.6.5 鏇村鐨?ACK 鍧?/span>

涓€鑸潵璇达紝鎺ユ敹鏂规敹鍒板彂閫佹柟鐨勬秷鎭悗閮藉簲璇ュ彂閫佷竴涓?ACK 鍥炲锛岃〃绀烘敹鍒颁簡鏁版嵁銆備絾姣忔敹鍒颁竴涓暟鎹氨杩斿洖涓€涓?ACK 鍥炲澶夯鐑︼紝鎵€浠ヤ竴鑸笉浼氱珛鍗冲洖澶嶏紝鑰屾槸鎺ユ敹鍒板涓暟鎹悗鍐嶅洖澶嶏紝TCP SACK 鏈€澶氭彁渚?3 涓?ACK block銆備絾鏈変簺鍦烘櫙涓嬶紝姣斿涓嬭浇锛屽彧闇€瑕佹湇鍔″櫒杩斿洖鏁版嵁灏卞ソ锛屼絾鎸夌収 TCP 鐨勮璁★紝姣忔敹鍒?3 涓暟鎹寘灏辫鈥滅ぜ璨屾€р€濆湴杩斿洖涓€涓?ACK銆傝€?QUIC 鏈€澶氬彲浠ユ崕甯?256 涓?ACK block銆傚湪涓㈠寘鐜囨瘮杈冧弗閲嶇殑缃戠粶涓嬶紝鏇村鐨?ACK block 鍙互鍑忓皯閲嶄紶閲忥紝鎻愬崌缃戠粶鏁堢巼銆?/span>

1.7 娴侀噺鎺у埗

TCP 浼氬姣忎釜 TCP 杩炴帴杩涜娴侀噺鎺у埗锛屾祦閲忔帶鍒剁殑鎰忔€濇槸璁╁彂閫佹柟涓嶈鍙戦€佸お蹇紝瑕佽鎺ユ敹鏂规潵寰楀強鎺ユ敹锛屼笉鐒朵細瀵艰嚧鏁版嵁婧㈠嚭鑰屼涪澶憋紝TCP 鐨勬祦閲忔帶鍒朵富瑕侀€氳繃婊戝姩绐楀彛鏉ュ疄鐜扮殑銆傚彲浠ョ湅鍑猴紝鎷ュ鎺у埗涓昏鏄帶鍒跺彂閫佹柟鐨勫彂閫佺瓥鐣ワ紝浣嗘病鏈夎€冭檻鍒版帴鏀舵柟鐨勬帴鏀惰兘鍔涳紝娴侀噺鎺у埗鏄杩欓儴鍒嗚兘鍔涚殑琛ラ綈銆?/span>

QUIC 鍙渶瑕佸缓绔嬩竴鏉¤繛鎺ワ紝鍦ㄨ繖鏉¤繛鎺ヤ笂鍚屾椂浼犺緭澶氭潯 Stream锛屽ソ姣旀湁涓€鏉￠亾璺紝涓ゅご鍒嗗埆鏈変竴涓粨搴擄紝閬撹矾涓湁寰堝杞﹁締杩愰€佺墿璧勩€俀UIC 鐨勬祦閲忔帶鍒舵湁涓や釜绾у埆锛氳繛鎺ョ骇鍒紙Connection Level锛夊拰 Stream 绾у埆锛圫tream Level锛夛紝濂芥瘮鏃㈣鎺у埗杩欐潯璺殑鎬绘祦閲忥紝涓嶈涓€涓嬪瓙寰堝杞﹁締娑岃繘鏉ワ紝璐х墿鏉ヤ笉鍙婂鐞嗭紝涔熶笉鑳戒竴涓溅杈嗕竴涓嬪瓙杩愰€佸緢澶氳揣鐗╋紝杩欐牱璐х墿涔熸潵涓嶅強澶勭悊銆?/span>

閭?QUIC 鏄€庝箞瀹炵幇娴侀噺鎺у埗鐨勫憿锛熸垜浠厛鐪嬪崟鏉?Stream 鐨勬祦閲忔帶鍒躲€係tream 杩樻病浼犺緭鏁版嵁鏃讹紝鎺ユ敹绐楀彛锛坒low control receive window锛夊氨鏄渶澶ф帴鏀剁獥鍙ｏ紙flow control receive window锛夛紝闅忕潃鎺ユ敹鏂规帴鏀跺埌鏁版嵁鍚庯紝鎺ユ敹绐楀彛涓嶆柇缂╁皬銆傚湪鎺ユ敹鍒扮殑鏁版嵁涓紝鏈夌殑鏁版嵁宸茶澶勭悊锛岃€屾湁鐨勬暟鎹繕娌℃潵寰楀強琚鐞嗐€傚涓嬪浘鎵€绀猴紝钃濊壊鍧楄〃绀哄凡澶勭悊鏁版嵁锛岄粍鑹插潡琛ㄧず鏈鐞嗘暟鎹紝杩欓儴鍒嗘暟鎹殑鍒版潵锛屼娇寰?Stream 鐨勬帴鏀剁獥鍙ｇ缉灏忋€?/span>

闅忕潃鏁版嵁涓嶆柇琚鐞嗭紝鎺ユ敹鏂瑰氨鏈夎兘鍔涘鐞嗘洿澶氭暟鎹€傚綋婊¤冻 (flow control receive offset - consumed bytes) < (max receive window / 2) 鏃讹紝鎺ユ敹鏂逛細鍙戦€?WINDOW_UPDATE frame 鍛婅瘔鍙戦€佹柟浣犲彲浠ュ啀澶氬彂閫佷簺鏁版嵁杩囨潵銆傝繖鏃?flow control receive offset 灏变細鍋忕Щ锛屾帴鏀剁獥鍙ｅ澶э紝鍙戦€佹柟鍙互鍙戦€佹洿澶氭暟鎹埌鎺ユ敹鏂广€?/span>

Stream 绾у埆瀵归槻姝㈡帴鏀剁鎺ユ敹杩囧鏁版嵁浣滅敤鏈夐檺锛屾洿闇€瑕佸€熷姪 Connection 绾у埆鐨勬祦閲忔帶鍒躲€傜悊瑙ｄ簡 Stream 娴侀噺閭ｄ箞涔熷緢濂界悊瑙?Connection 娴佹帶銆係tream 涓紝鎺ユ敹绐楀彛(flow control receive window) = 鏈€澶ф帴鏀剁獥鍙?max receive window) - 宸叉帴鏀舵暟鎹?highest received byte offset) 锛岃€屽 Connection 鏉ヨ锛氭帴鏀剁獥鍙?= Stream1 鎺ユ敹绐楀彛 + Stream2 鎺ユ敹绐楀彛 + ... + StreamN 鎺ユ敹绐楀彛 銆?/span>

2. 鎬荤粨

QUIC 涓㈡帀浜?TCP銆乀LS 鐨勫寘琚憋紝鍩轰簬 UDP锛屽苟瀵?TCP銆乀LS銆丠TTP/2 鐨勭粡楠屽姞浠ュ€熼壌銆佹敼杩涳紝瀹炵幇浜嗕竴涓畨鍏ㄩ珮鏁堝彲闈犵殑 HTTP 閫氫俊鍗忚銆傚嚟鍊熺潃 0 RTT 寤虹珛杩炴帴銆佸钩婊戠殑杩炴帴杩佺Щ銆佸熀鏈秷闄や簡闃熷ご闃诲銆佹敼杩涚殑鎷ュ鎺у埗鍜屾祦閲忔帶鍒剁瓑浼樼鐨勭壒鎬э紝QUIC 鍦ㄧ粷澶у鏁板満鏅笅鑾峰緱浜嗘瘮 HTTP/2 鏇村ソ鐨勬晥鏋溿€?/span>

涓€鍛ㄥ墠锛屽井杞甯冨紑婧愯嚜宸辩殑鍐呴儴 QUIC 搴?-- MsQuic锛屽皢鍏ㄩ潰鎺ㄨ崘 QUIC 鍗忚鏇挎崲 TCP/IP 鍗忚銆?/span>

HTTP/3 鏈潵鍙湡銆?/span>

END

鍘嗗彶鎺ㄨ崘

鐐逛釜鍦ㄧ湅鍚?/span>