Sareko ingeniariek sarritan aurkitzen dituzte TCPren leiho edo aplikazioen errendimendua sareko azpiegiturei egozten zaien egoerak. Paketeen kaptura, tcpdumps eta sareko analisia egin ondoren, benetako botila-lepoa aurkitu ohi da: NIC agortua (Network Interface Card) edo OS mailako bufferrak bezeroaren edo zerbitzari-sistemetan.
Artikulu honek ondare (2009 inguruan) eta uneko (2025-2026) buffer-konfigurazioak eskaintzen ditu Linux, Windows eta macOSentzat, baita diagnostiko-teknikak ere, bufferraren nekea identifikatzeko arazo larria izan aurretik.
TCPk fluxu-kontrolaren mekanismo bat erabiltzen du, non hartzaileak "leiho-tamaina" iragartzen duen, zenbat datu onartzen dituen adieraziz. Sistemaren bufferrak betetzen direnean, leiho hau zerorantz jaisten da, bidaltzaileak itxaron dezan. Sareko arazoa dirudi, baina ostalari-baliabideen arazoa da.
# Check current TCP buffer settings sysctl net.ipv4.tcp_rmem sysctl net.ipv4.tcp_wmem sysctl net.core.rmem_max sysctl net.core.wmem_max # Check NIC ring buffer sizes ethtool -g eth0 # Monitor socket buffer usage ss -tm # Check for TCP zero window events tcpdump -i any 'tcp[tcpflags] & tcp-push != 0' -vv # Check network statistics for buffer issues netstat -s | grep -i "buffer\|queue\|drop"
# Check TCP parameters
netsh interface tcp show global
# View network adapter buffer settings
Get-NetAdapterAdvancedProperty -Name "Ethernet" | Where-Object {$_.DisplayName -like "*buffer*"}
# Monitor TCP statistics
netstat -s -p tcp
# Check receive window auto-tuning
netsh interface tcp show global | findstr "Receive Window"
# Check current buffer settings sysctl kern.ipc.maxsockbuf sysctl net.inet.tcp.sendspace sysctl net.inet.tcp.recvspace # View network statistics netstat -s -p tcp # Monitor socket buffers netstat -an -p tcp
| Parametroa | Ondarearen balioa (2009) | Azalpena |
|---|---|---|
| net.core.rmem default | 124928 (122KB) | Onartutakoen bufferraren tamaina lehenetsia |
| net.core.rmem max | 131071 (128KB) | Jaso gehienezko bufferraren tamaina |
| net.core.wmem default | 124928 (122KB) | Bidali socket bufferraren tamaina lehenetsia |
| net.core.wmem max | 131071 (128KB) | Bidali socket bufferraren gehienezko tamaina |
| net.ipv4.tcp rmem | 4096 87380 174760 | TCPk bufferra jasotzen du: min, default, max (bytetan) |
| net.ipv4.tcp wmem | 4096 16384 131072 | TCPk bufferra bidaltzen du: min, default, max (bytetan) |
| net.ipv4.tcp mem | 196608 262144 393216 | TCP memoria orriak: baxua, presioa, altua |
| net.core.netdev max backlog | 1000 | Gehienezko paketeak sarrerako ilaran |
| net.core.optmem max | 10240 (10KB) | Bufferraren gehienezko tamaina socket bakoitzeko |
| Parameter | Uneko gomendatutako balioa | Description |
|---|---|---|
| net.core.rmem_default | 16777216 (16MB) | Default receive socket buffer size |
| net.core.rmem_max | 134217728 (128MB) | Maximum receive socket buffer size |
| net.core.wmem_default | 16777216 (16MB) | Default send socket buffer size |
| net.core.wmem_max | 134217728 (128MB) | Maximum send socket buffer size |
| net.ipv4.tcp_rmem | 4096 87380 134217728 | TCPk bufferra jasotzen du: min, default, max (128MB gehienez) |
| net.ipv4.tcp_wmem | 4096 65536 134217728 | TCPk bufferra bidaltzen du: min, default, max (128MB gehienez) |
| net.ipv4.tcp_mem | 8388608 12582912 16777216 | TCP memoria orriak: baxua, presioa, altua (64GB sistema) |
| net.core.netdev_max_backlog | 250000 | Gehienezko paketeak sarrerako ilaran (10GbE+) |
| net.core.optmem_max | 65536 (64KB) | Maximum ancillary buffer size per socket |
| net.ipv4.tcp congestion control | bbr | Erabili BBR kongestioaren kontrola (Googleren algoritmoa) |
| net.ipv4.tcp window scaling | 1 | Gaitu TCP leihoen eskalatzea (RFC 1323) |
| net.ipv4.tcp timestamps | 1 | Gaitu TCP ordu-zigiluak RTT estimatzeko |
| net.ipv4.tcp sack | 1 | Gaitu aitortza selektiboa |
| net.ipv4.tcp no metrics save | 1 | Desgaitu TCP metriken cachea |
Gehitu ezarpen hauek /etc/sysctl.conf edo fitxategi berria sortu /etc/sysctl.d/99-network-tuning.conf:
# Network Buffer Tuning for High-Performance Applications # Optimized for 10GbE+ networks with RTT up to 300ms # Core socket buffer settings net.core.rmem_default = 16777216 net.core.rmem_max = 134217728 net.core.wmem_default = 16777216 net.core.wmem_max = 134217728 # TCP buffer settings net.ipv4.tcp_rmem = 4096 87380 134217728 net.ipv4.tcp_wmem = 4096 65536 134217728 net.ipv4.tcp_mem = 8388608 12582912 16777216 # Device buffer settings net.core.netdev_max_backlog = 250000 net.core.netdev_budget = 50000 net.core.netdev_budget_usecs = 5000 net.core.optmem_max = 65536 # TCP optimizations net.ipv4.tcp_congestion_control = bbr net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_timestamps = 1 net.ipv4.tcp_sack = 1 net.ipv4.tcp_no_metrics_save = 1 net.ipv4.tcp_moderate_rcvbuf = 1 # Apply with: sysctl -p /etc/sysctl.d/99-network-tuning.conf
# Check current ring buffer sizes ethtool -g eth0 # Set maximum ring buffer sizes (adjust based on NIC capabilities) ethtool -G eth0 rx 4096 tx 4096 # Make persistent by adding to /etc/network/interfaces or systemd service
| Parameter | Legacy Value (2009) | Kokalekua |
|---|---|---|
| TcpWindowSize | 65535 (64KB) | Erregistroa: HKLM\System\CurrentControlSet\Services\Tcpip\Parametroak |
| Tcp1323Opts | 0 (desgaituta) | Leihoaren eskala desgaituta lehenespenez |
| Leiho lehenetsia | 8192 (8KB) | Jasotzeko leiho lehenetsia |
| Lehenetsitako leihoa | 8192 (8KB) | Bidaltzeko leiho lehenetsia |
| GlobalMaxTcpWindowSize | 65535 (64KB) | TCP leihoaren gehienezko tamaina |
| TcpNumConnections | 16777214 | TCP konexio maximoak |
Leiho modernoek erabiltzen dute Jaso leihoa automatikoki elkartzea Ezaugarri horrek, dinamikoki doitzen denak, bufferrak jasotzen ditu sare-baldintzen arabera.
| Eginbidea | Gomendatutako ezarpenak | Description |
|---|---|---|
| Elkartze maila automatikoa | normala (edo oso esperimentala 10GbE+erako) | Jaso leihoa doitzea |
| Jaso-Side Scaling (RSS) | gaituta | Banatu sareko prozesamendua PUZetan zehar |
| Chimney Offload | automatikoa (edo desgaitu NIC modernoetan) | TCP deskargatu hardware NIC-ra |
| NetDMA | desgaituta | Zuzeneko Memoria Sarbidea (zaharkitua) |
| TCP parametro orokorrak | Komandoak behean | Sistema osoko TCP ezarpenak |
| Congestion hornitzailea | CUBIC (edo NewRenoko jaitsiera) | TCP kongestio-kontrolaren algoritmoa |
# Check current auto-tuning level netsh interface tcp show global # Enable auto-tuning (normal mode - default for most scenarios) netsh interface tcp set global autotuninglevel=normal # For high-bandwidth, high-latency networks (10GbE+, data center environments) netsh interface tcp set global autotuninglevel=experimental # For conservative tuning (if experimental causes issues) netsh interface tcp set global autotuninglevel=restricted # For very conservative tuning (not recommended for high-performance networks) netsh interface tcp set global autotuninglevel=highlyrestricted # Enable CUBIC congestion provider (Windows Server 2022/Windows 11+ only) netsh interface tcp set supplemental template=Internet congestionprovider=cubic # Note: Windows 10 and Server 2019 use Compound TCP or NewReno by default # CUBIC is not available on these older versions # Enable Receive-Side Scaling (RSS) netsh interface tcp set global rss=enabled # Set chimney offload (automatic is recommended) netsh interface tcp set global chimney=automatic # Disable NetDMA (recommended for modern systems) netsh interface tcp set global netdma=disabled # Enable Direct Cache Access (if supported) netsh interface tcp set global dca=enabled # Enable ECN (Explicit Congestion Notification) netsh interface tcp set global ecncapability=enabled # Set initial congestion window to 10 (RFC 6928) netsh interface tcp set global initialRto=3000
# View current adapter settings Get-NetAdapterAdvancedProperty -Name "Ethernet" # Increase receive buffers (adjust based on NIC) Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Receive Buffers" -DisplayValue 2048 # Increase transmit buffers Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Transmit Buffers" -DisplayValue 2048 # Enable Jumbo Frames (if network supports it) Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Jumbo Packet" -DisplayValue 9014 # Enable Large Send Offload (LSO) Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Large Send Offload V2 (IPv4)" -DisplayValue Enabled Set-NetAdapterAdvancedProperty -Name "Ethernet" -DisplayName "Large Send Offload V2 (IPv6)" -DisplayValue Enabled
# These settings are typically NOT needed on Windows 10/11 due to auto-tuning # Only modify if auto-tuning is disabled or problematic # Registry path: HKLM\System\CurrentControlSet\Services\Tcpip\Parameters # Maximum TCP window size (if auto-tuning disabled) # TcpWindowSize = 16777216 (16MB) - REG_DWORD # Enable window scaling (enabled by default on modern Windows) # Tcp1323Opts = 3 - REG_DWORD # Number of TCP Timed Wait Delay # TcpTimedWaitDelay = 30 - REG_DWORD (default 240)
| Parameter | Legacy Value (2009) | Description |
|---|---|---|
| kern.ipc.maxsockbuf | 262144 (256KB) | Socket-aren bufferraren gehienezko tamaina |
| net.inet.tcp.sendspace | 32768 (32KB) | TCPren buffer lehenetsia |
| net.inet.tcp.recvspace | 32768 (32KB) | TCP lehenetsiaren bufferra |
| net.inet.tcp.autorcvbufmax | 131072 (128KB) | Automatikoki doitutako gehienezko bufferra |
| net.inet.tcp.autosndbufmax | 131072 (128KB) | Bidalitako gehienezko bufferra |
| net.inet.tcp.rfc1323 | 0 (disabled) | TCP leihoa eskalatzea |
| Parameter | Current Recommended Value | Description |
|---|---|---|
| kern.ipc.maxsockbuf | 8388608 (8MB) | Maximum socket buffer size |
| net.inet.tcp.sendspace | 131072 (128KB) | Default TCP send buffer |
| net.inet.tcp.recvspace | 131072 (128KB) | Default TCP receive buffer |
| net.inet.tcp.autorcvbufmax | 16777216 (16MB) | Maximum auto-tuned receive buffer |
| net.inet.tcp.autosndbufmax | 16777216 (16MB) | Maximum auto-tuned send buffer |
| net.inet.tcp.rfc1323 | 1 (gaituta) | Gaitu TCP leihoa eskalatzea |
| net.inet.tcp.sack | 1 (enabled) | Enable Selective Acknowledgment |
| net.inet.tcp.msdflt | 1440 | TCPren gehienezko segmentuaren tamaina lehenetsia |
| net.inet.tcp.delayed ack | 3 | Atzeratutako ACK portaera |
# Check current settings sysctl kern.ipc.maxsockbuf sysctl net.inet.tcp.sendspace sysctl net.inet.tcp.recvspace sysctl net.inet.tcp.autorcvbufmax sysctl net.inet.tcp.autosndbufmax # Apply settings temporarily (until reboot) sudo sysctl -w kern.ipc.maxsockbuf=8388608 sudo sysctl -w net.inet.tcp.sendspace=131072 sudo sysctl -w net.inet.tcp.recvspace=131072 sudo sysctl -w net.inet.tcp.autorcvbufmax=16777216 sudo sysctl -w net.inet.tcp.autosndbufmax=16777216 sudo sysctl -w net.inet.tcp.rfc1323=1 sudo sysctl -w net.inet.tcp.sack=1 # Make settings persistent (create /etc/sysctl.conf) sudo tee /etc/sysctl.conf <Ezarpen iraunkorretarako daemon-a sortzea
# Create /Library/LaunchDaemons/com.local.sysctl.plist sudo tee /Library/LaunchDaemons/com.local.sysctl.plist <EOF sudo chmod 644 /Library/LaunchDaemons/com.local.sysctl.plist sudo launchctl load /Library/LaunchDaemons/com.local.sysctl.plist Label com.local.sysctl ProgramArguments /usr/sbin/sysctl -w kern.ipc.maxsockbuf=8388608 RunAtLoad Abisua: macOS Ventura (13) eta gero Sistema Osotasunaren Babesa (SIP) murriztapenak ditu. Nukleoaren parametro batzuk ezin dira aldatu sudoarekin ere. Proba-ezarpenak ingurune jakin batean.
# Server side iperf3 -s # Client side - test TCP throughput iperf3 -c server_ip -t 60 -i 5 -w 16M # Test with multiple parallel streams iperf3 -c server_ip -P 10 -t 60 # Test UDP performance iperf3 -c server_ip -u -b 1000M -t 60
# Capture and display TCP window sizes tcpdump -i any -n 'tcp' -vv | grep -i window # Save capture for Wireshark analysis tcpdump -i any -w /tmp/capture.pcap 'tcp port 443'
Bilatu bufferreko arazoen adierazle hauek:
# Linux - Monitor network buffer statistics watch -n 1 'cat /proc/net/sockstat' watch -n 1 'ss -tm | grep -i mem' # Check for drops netstat -s | grep -i drop # Windows - Monitor TCP statistics netstat -e 1 # macOS - Monitor network statistics netstat -s -p tcp
Sarearen bufferraren tamaina optimoa zehazteko, kalkulatu Bandwidth-Delay Produktua:
BDP = Bandwidth (bits/sec) × RTT (seconds) Example for 10 Gigabit Ethernet with 50ms RTT: BDP = 10,000,000,000 × 0.050 = 500,000,000 bits = 62.5 MB Buffer Size = BDP × 2 (for bidirectional traffic and headroom) Buffer Size = 62.5 MB × 2 = 125 MB This is why modern settings recommend 128MB maximum buffers.
| Lan-karga mota | Gomendatutako bufferraren tamaina | Gakoaren parametroak |
|---|---|---|
| Web zerbitzaria (latentzia baxua) | 4-16 MB | Jaitsi bufferrak, konexio gehiago, erantzun azkarra |
| Datu-basearen zerbitzaria | 16-32 MB | Buffer moderatuak, irteera koherentea |
| Fitxategi-transferentzia / babeskopia | 64-128 MB | Gehienezko bufferrak, irteera handiko lehentasuna |
| Bideo-korrontea | 32-64 MB | buffer handiak, entrega-tasa konstantea |
| HPC / Datuen Zentroa | 128-256 MB | Gehienezko bufferrak, kongestioaren kontrol espezializatua |
| Haririk gabekoa / mugikorra | 2-8 MB | Buffer kontserbadoreak, latentzien kudeaketa aldakorra |
Bufferraren nekea sareko arazoen erro-kausa da. 2009ko 128KB-tik 128MB-ra bitarteko bufferraren bilakaera ulertuz, sareko ingeniariek berehala identifikatu eta ebatzi ditzakete arazo horiek.
Gako-iruzkinak:
Gogoratu: paketeen analisiak TCP zero leihoak erakusteko "sare-arazoa" ostalari-sistemaren baliabideen arazoa da. Bufferraren doikuntza egokiarekin, diagnostiko faltsu horiek ezabatu eta errendimendu optimoa lor dezakezu.
Azken eguneraketa: otsailak 2, 2026
Egilea: Baud9600 Talde teknikoa