A 2021 IIE/CAS master's thesis (author and advisor names redacted) solves carrier-scale asymmetric routing for stateful DPI/firewall deployment using programmable (P4) switches: an MV-Sketch-based traffic-distribution measurement ported to switch hardware, plus a decision-tree-derived, TCAM-compressed forwarding table ("SortMerging," 42% compression) that cuts traffic-alignment bandwidth overhead by 74.6% versus hash-based forwarding — directly addressing the single-vantage-point blind spot that asymmetric ISP routing creates for inline DPI/stateful-firewall systems like SAPP.
互联网中广泛存在的非对称路由现象，导致网络中的单个节点无法观测到完整流量。这一现象给流量处理带来了显著的挑战，使得如深度报文检测、有状态防火墙、精确流量计费等技术难以实施...在测试数据集上，基于构造的转发表实施流量对准比基于哈希的转发方法减少了74.6%的带宽开销。
Related findings
An internal TSG operations/troubleshooting manual lays out TSG's full traffic pipeline (NIC -> mrzcpd/marsio capture driver -> sapp DPI engine -> firewall/proxy(KNI->TFE)/active-defense/WAN-NAT policy branches) and shows engineers using maat_redis_tool to pull the live Redis-synced blocking policy tables (TSG_SECURITY_COMPILE, TSG_OBJ_IP_ADDR, TSG_OBJ_APP_ID) and filter them by numeric policy/object ID to debug why a block rule isn't firing.
The internal 'MAAT网络流处理配置统一描述框架' engineering manual (v3.1.20, author name redacted, 2021) documents MAAT's Redis-synced rule-compilation framework and its RuleScan/Hyperscan-based pattern-matching engine (libmaatframe.so / librulescan), and records that RuleScan's fast-scan feature caused a production outage on 2019-03-19 and has been disabled ever since.
An internal design note for a 'Shadowsocks traffic parsing/restoration module' describes decrypting captured Shadowsocks payloads back to the original HTTP request/response, given a known pre-shared key (AES-256-CFB, MD5-derived key, IV embedded in the stream).
A dedicated internal "运营商前端分析团队" (Carrier Front-end Analysis Team) produces weekly, carrier-specific traffic-analysis reports explicitly titled "新疆移动流量分析报告" (Xinjiang Mobile Traffic Analysis Report) and "新疆联通流量分析报告" (Xinjiang Unicom Traffic Analysis Report), with instances dated from at least July 2022 through March 2024. One instance (Xinjiang Mobile, 2023-05-15) reports total carrier bandwidth of 4.4Tbps (1Tbps access bandwidth), 27.34PB of weekly throughput, 123 distinct identified application-layer protocols, and a section (4.1, pages 17+) explicitly tracking server IP/location for 28 named overseas apps (BBC, Discord, ESPN, Facebook, Gmail, Google, Hulu, Instagram, Netflix, Reddit, Skype, Telegram, Twitter, Uber, WhatsApp, Wikipedia, YouTube, Zoom, etc.).
The same 2024 IIE CAS thesis proposes 'PED' (Packet-context based Evasion Detection): an XGBoost flow-feature pre-filter followed by a GRU-based autoencoder trained on packet-context features (inter-packet plus protocol-layer, including HTTP-layer fields) that flags DPI-evasion traffic via reconstruction error, reporting accuracy/ROC-AUC above 0.88/0.97 and generalizing to the public CICIDS and MAWI datasets; the thesis also proposes a deployable LAN-gateway evasion-detection prototype and four DPI-middlebox hardening recommendations (mimic Suricata's strict field validation, enforce RFC-compliant parsing, add ML-based anomaly detection, run regular red-team evaluations).
A 2018 MESA Lab monthly report describes work on the "GPS"/"先导" (Pioneer) active-probing projects: adding IPv6 scanning support and simultaneous 3-domain scanning to MAAT, alongside active-probing experiments (nslookup/dig/nmap) and root-DNS-server BGP-anycast measurement -- indicating MAAT's rule engine is paired with an active network-scanning subsystem, not purely passive/inline matching.