架構視角解讀網絡加速 ：基於公有云的方案已經過時了？

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":3}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"link","attrs":{"href":"https:\/\/help.aliyun.com\/document_detail\/153189.html","title":"xxx","type":null},"content":[{"type":"text","text":"GA（Global Accelerator）全球加速"}]},{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"，是個讓人覺得“既熟悉又陌生”的行業。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“熟悉”是指，GA 不是個新詞彙，你幾乎能在所有公有云廠商的產品介紹下，看見 GA 這項服務。做出海、遊戲類業務的人都太熟悉 GA 了，沒有它 ，基本的網絡連通都將成爲問題。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“陌生”則是說，即便在疫情的催化下，GA 行業依然很少出現在開發者社區的主流視野中。在疫情爆發的這兩年間，我們頻繁談起數字化轉型、智能數據平臺、RTC，可就是很少談起 GA。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"爲何會出現這樣古怪的情況呢？有一種可能是：雖然 GA 服務非常關鍵，但它屬於基礎設施，在技術層面暫時沒有太多的想象空間，缺少跨越式發展，因而討論熱度較低。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"前不久，聲網發佈了 "},{"type":"link","attrs":{"href":"https:\/\/www.agora.io\/cn\/fpa\/","title":"xxx","type":null},"content":[{"type":"text","text":"FPA"}]},{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" 全鏈路加速產品，乍一看與 GA 相仿，又存在截然不同的技術特徵，格外讓人好奇。因此，InfoQ 特別採訪了 FPA 的產品負責人施政與聲網基礎平臺技術負責人王浩宇，希望能在架構和產品的視角對 FPA 進行解讀，從中尋找關於全球加速服務的新的啓發。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"爲何“最後一公里”問題無人問津？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"要更好地理解聲網 FPA ，首先要了解 GA 的工作原理。簡單來說，GA 服務一般由公有云廠商提供，會爲用戶分配少數接入 IP，保證用戶就近接入公有云加速網絡，再通過各個節點間的加速鏈路，配合動態的調度策略，實現傳輸層的網絡加速。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"GA 加速方案是開創性的，它將單一用戶納入公有云龐大的基礎設施資源裏，進行跨地域跨運營商加速，並以雲的方式，自底向上融合了多種加速技術，包括 CDN、專線網絡。而在此前，無論是 CDN 加速方案還是專線加速方案，彼此都是孤立存在的，而且都是主要在物理層面使勁，忽略了軟件層面，顯得有點粗獷。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"但 GA 加速方案也不是完美的，它存在許多天然劣勢，其中之一便是“最後一公里”問題：以 IP 協議接入加速網絡，意味着在接入前，沒有端側 QoS 保障。具體來說，如果用戶如果通過 Wi-Fi 接入，將面臨 Wi-Fi 設備性能差異、信道競爭等多種問題；如果通過 4G、5G 信號接入，則會因環境不同，造成信號強度不同，出現網絡性能波動。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"聲網 FPA 的一個重要技術特點便是解決終端接入問題，而這種解決方案主要是通過在終端、服務端集成 FPA SDK 來實現的。通過 SDK， FPA 構建了一種覆蓋任意端到任意端的全鏈路加速通道，這也是 FPA（Full-Path Accelerator）名字的來源。SDK 集成後，從端側到骨幹網，弱網對抗、智能接入、自主決策、冗餘接入等多種技術方案都可以發揮作用，這是該種方案爲用戶體驗帶來的最直觀的改善。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"弱網對抗不必多說，這是所有視頻會議、RTC行業從業者都必須解決且保持長期關注的問題。智能接入、自主決策是指 SDK 會向調度中心請求一份路由列表，已獲知最近入口，並根據路由列表自主決策在何處接入，避免與調度中心反覆通信增加延遲。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"冗餘接入是指 SDK 會和多個入口建立連接，傳輸相同的數據包，保證高可用，減少重傳延遲。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"聽起來，集成 SDK 對整體加速性能的提升，還是非常有益處的。但此前，無論是 CDN 服務提供商，還是 GA 服務提供商，都無法提供成熟的 SDK 集成服務。"},{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}},{"type":"strong"}],"text":"不是大家不想，而是因爲不能。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"FPA 產品負責人施政說：“因爲大家一直以來提供的都是一種標準的web服務。在這個場景下，對開發者或者對於用戶來講，端側集成是不能接受的。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“但在聲網的實時互動領域，”他補充道，“開發者已經接受了聲網使用SDK的方式作爲他們的開發組件。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"情況也確實如此，SDK 一直是聲網長期以來的主要服務模式。2020年10月， 聲網 Agora 創始人兼 CEO 趙斌在"},{"type":"link","attrs":{"href":"https:\/\/www.rteconf.com\/2021","title":"xxx","type":null},"content":[{"type":"text","text":"RTE"}]},{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"大會上宣佈，客戶主動調用 API 次數突破 100 億次\/日。而聲網最新的財報也顯示，截至2021年6月30日，聲網全球註冊應用超33.7萬個。這些無疑都是非常驚人的數據。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"SDK 集成的方案對業務的侵入性很強。如果 SDK 不穩定，且業務模塊沒有做好邊界測試和限制，相關故障很容易殃及整個系統。且與雲服務不同，SDK 的代碼是暴露的，當系統故障時，可能會讓問題變得更復雜。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"但任何方案都有兩面性，SDK 方案的問題，同樣也促使聲網在軟件研發層面，構建出了自身的技術壁壘——"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“聲網 SDK 的崩潰率是 0.5 ‱（萬分之零點五），在行業內是最低的，沒有經過洗禮是達不到這種程度的。”施政說。"}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"一個“異類”：基於 SD-RTN™ 的骨幹網傳輸優化"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"除了端側的覆蓋問題，FPA 在骨幹網層面的加速策略，也與傳統 GA 服務完全不同。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"FPA 的骨幹網加速能力是基於聲網 "},{"type":"link","attrs":{"href":"https:\/\/www.agora.io\/cn\/sd-rtn","title":"xxx","type":null},"content":[{"type":"text","text":"SD-RTN™"}]},{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" 構建的。SD-RTN™ 在架構層面分爲三層："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"第一層：數據層。數據層負責數據的實時傳輸和轉發，並負責將當前的狀態數據上報給控制層。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"第二層：控制層。控制層類似一個網絡操作系統，完成的是傳統Internet的工作，包括尋址、計算並下發路由地址、控制傳輸的拓撲結構等。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"第三層：應用層。應用層面向業務邏輯，同時會針對實時音視頻場景做特別的優化。比如更改關鍵幀的處理策略、進行協議適配等。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"這樣的架構在 2019 年具備雛形，於 2020 - 2021 的兩年間逐漸成熟。與傳統的專線網絡不同，SD-RTN™構建在公共互聯網上，使數據中心、企業內部以外的任何用戶的終端都可以訪問，對硬件的依賴很小；另外，SD-RTN™的數據中心分佈在全球數百個節點，保證了通訊的舒暢。同時，聲網也在探索自建機房，以此解決複雜的運營商問題，更好的控制成本。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"SD-RTN™ 無論在 RTC 領域還是在網絡加速領域，都算的上是一個“異類”。發展至今，業內最主流的網絡加速和低延時解決方案，還是基於 CDN 構建的，與 SD-RTN™ 在架構設計上幾乎背道而馳。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"作爲歷史悠久的內容分發解決方案，CDN 採用多級緩存的機制，依靠部署在各地的邊緣服務器，通過中心平臺的負載均衡、內容分發、調度等功能模塊，使用戶就近獲取所需內容，降低網絡擁塞，提高用戶訪問響應速度和命中率。更爲重要的一點是，運行在 CDN 之上的傳輸協議，大多基於 TCP。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"而 SD-RTN™ 在建立之初就把傳輸層協議確定爲 UDP，以規避 TCP 因握手、超時重傳機制帶來的高延遲。同時 SD-RTN™ 在對緩存的控制非常謹慎。用聲網基礎平臺技術負責人王浩宇的話說，就是“如何用最小的緩存去實現最優的效果”。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"他也補充道：“FPA 很難對數據做緩存，這個跟 CDN 做靜態加速完全是不一樣的效果。你會發現有的時候緩存沒啥用，比如最近有一個從 CDN 切到聲網的用戶，應用場景是上傳課件，上課馬上就要用。他們發現，基於 CDN 的加速效果很差。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“爲什麼呢？”他說，“因爲要建立緩存，其實需要付出很大的代價，而且如果沒有一些預熱，可能這個緩存的效果根本就不盡如人意。CDN 分發非常便宜，但它有使用前提，就是你一定得高頻擊中緩存，否則效果不好。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"當然，SD-RTN™ 和 CDN 在資源側沒有隔閡，聲網的思路是基於用戶需求，定向的增加某個地區的節點覆蓋。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"究竟 CDN 和 SD-RTN™ 哪種方案效果更好？這裏不好下定論，CDN 也在不斷針對低延時場景進行優化。但從新東方、陌陌等企業的實際使用效果來看，SD-RTN™ 確實能夠解決問題，並且在架構設計和未來擴展層面，可能更適合實時互動場景。"}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"自研 AUT 協議：傳輸層的優化更有想象空間"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"聲網 FPA 的另一個技術特點在於其自研的 AUT 協議，架構示意如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/e3\/e396ecfaa24679ff8b6edfb42814849d.jpeg","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"在發佈會上，聲網也發佈了，AUT 協議和以 TCP 爲代表的公共協議，在三種情況下的抗弱網效果數據。實驗方法是發送1000個消息數據並記錄其到達時間，實驗結果如下圖。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/1b\/1bc0c0469eb6ff5ec3dcacb37167afb6.jpeg","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"可以看出，對比 TCP 類公共協議，AUT 協議在限速和丟包場景中，平均消息到達延遲分別下降 53% 和 67% ，在同時限速與丟包的極端場景下，平均消息延遲下降55%。數據表現非常不錯。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"AUT 協議的開放，同時給 FPA 帶來了另一個與傳統 GA 方案不同的特性。GA 雖然是基於公有云進行鏈路加速的，但所涉及的一般不止是“一朵雲”或一個運營商，跨雲、跨運營商是常見場景，這依賴於 BGP Anycast （邊界網關協議 + 泛播），也往往導致加速效果出現大幅波動。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"而 FPA 運行在 SD-RTN™ 之上，首先避免了多雲場景。更重要的是 AUT 是傳輸層協議，優化空間大於基於 IP 協議通信的 GA 服務。王浩宇在採訪中說："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“我們相信這樣是對開發者最友好，對於整個網絡傳輸過程來說，也是最可控的形式。我們通過端到端的傳輸能控制如何組包、協議怎麼重傳、怎麼做編碼側地優化，以及協議裏怎麼做連接的關閉和遷移，這些全都是我們可以去深入優化的細節。”"}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"無止境的質量問題"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"關於未來的產品迭代方向，王浩宇認爲還有大量的工作需要做："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“從產品視角來看，我們還是專注於開發者，思考能不能在更多的場景下，提供更易用的方法，比如代碼集成就可以獲得 FPA 的各項能力。另外從質量上來講，如何在各種網絡異常出現的情況下，還能保證用戶業務得到簡單處理？包括資源佈局、資源上的補充和替換，都是我們需要繼續加強的。”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"5G和雲遊戲也是一個場景上的挑戰。雲遊戲要求延時在 5ms 以內，在網絡條件差的情況下，如何實現這個目標？王浩宇說，這是聲網願意集中精力長期投入的事情。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"同時，聲網也並不認爲現在推出網絡加速服務“爲時已晚”。產品負責人施政說："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“以前大家總覺得，在網絡層做好管道，讓管道盡量靠近用戶就夠了，但從開發者的視角來看，真的是這樣嗎？開發者面對的端到端保障問題，有沒有人幫他解決？”"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#494949","name":"user"}}],"text":"“質量這個事情是無止境的。”"}]}]}