ltiprobe 0.3.0

HTTP/DNS/ICMP/TCP/TLS latency measurement tool with SLO validation and CDN detection

ltiprobe

HTTP/DNS/ICMP/TCP/TLS latency measurement tool with SLO validation and CDN detection. Displays a complete latency distribution (P50 to P99.9) from the terminal.

Installation

pip install ltiprobe

Usage

# Sites defined in ltiprobe.yaml (default)
ltiprobe

# Custom sites as arguments
ltiprobe https://apple.com https://amazon.com

# Number of measurements per site
ltiprobe -n 20

# Save results to CSV
ltiprobe --csv

# Show network hop count (traceroute)
ltiprobe --traceroute

# Use an alternate config file
ltiprobe --config-file staging.yaml

# Help
ltiprobe --help

Sample output

Measuring response times (10 attempts)...

https://google.com
  HTTP  distribution (10 measurements)
    average :  45.3 ms   min: 28.1   max: 145.2
    p50     :  38.0 ms
    p75     :  45.0 ms
    p90     :  62.0 ms
    p95     :  89.0 ms
    p99     : 145.0 ms
    p99.9   : 145.0 ms
  Stability : stable       (p99/p50 = 3.8x)
  DNS   -> average: 8.2 ms  min: 6.1  max: 11.4

  Network -> 14 hops  good       (≤ 25)  (3 hidden (* * *))

  --- Protocol comparison (cold connection) ---
  ICMP  (network)         :  12.3 ms  min: 11.1  max: 13.5  (10 packets)
  TCP   (port 443)        :  18.7 ms  min: 17.2  max: 21.0  (+6.4 ms)
  TLS   (handshake, ×1)   :  31.2 ms  min: 28.4  max: 35.1  (+12.5 ms)
  HTTP  (p50, cold)       :  38.0 ms  (+6.8 ms)
  HTTP  (p50, keep-alive) :  19.3 ms  ← no TCP/TLS

  ── Cache / CDN ──────────────────────────────────────
  Cache  →  HIT  Cloudflare  PoP: YYZ  Age: 42s

  ── HTTP Validation ──────────────────────────────────
  status_code     200                           →  200               ✓ OK
  body_contains   "google"                      →  found             ✓ OK

  ── SLO Analysis ─────────────────────────────────────
  http_p50_ms        38.0 ms  <=  300 ms        ✓ OK
  http_p95_ms        89.0 ms  <=  400 ms        ✓ OK
  dns_ms              8.2 ms  <=   50 ms        ✓ OK
  ────────────────────────────────────────────────────
  Summary: 3/3 objectives met

Configuration

Create a ltiprobe.yaml file at the root of your project:

nb_mesures: 10
timeout: 10
langue: EN        # EN or FR

sites:
  - url: https://api.example.com/health
    slo:
      http_p50_ms: 200      # max median HTTP latency
      http_p95_ms: 400      # max HTTP P95 latency
      dns_ms: 50            # max average DNS latency
      tls_ms: 80            # max TLS handshake
      icmp_ms: 30           # max network (ICMP) latency
      tcp_ms: 40            # max TCP handshake
      http_chaud_ms: 150    # max keep-alive HTTP (no TCP/TLS)
      stabilite_ratio: 5    # max P99/P50 ratio
      nb_hops_max: 25       # max network hops (--traceroute)
    assert:
      status_code: 200
      body_contains: "ok"
      header: "Content-Type: application/json"

If the file is absent, ltiprobe starts with default sites and values.

Available SLO keys

Key	Description
http_p50_ms	Median HTTP latency (P50)
http_p75_ms	HTTP P75 latency
http_p90_ms	HTTP P90 latency
http_p95_ms	HTTP P95 latency
http_p99_ms	HTTP P99 latency
http_p999_ms	HTTP P99.9 latency
dns_ms	Average DNS latency
tls_ms	TLS handshake duration
icmp_ms	Average ICMP network latency
tcp_ms	TCP handshake duration
http_chaud_ms	Estimated keep-alive HTTP (no TCP/TLS)
stabilite_ratio	P99/P50 ratio (e.g. 5 means P99 ≤ 5× P50)
nb_hops_max	Max network hops (requires --traceroute)

HTTP response validation (assert)

Key	Description
status_code	Expected HTTP status code (e.g. 200)
body_contains	String expected in the first 4 KB of the body
header	"Key: Value" (partial match) or "Key" (presence check)

Protocol layer comparison

ltiprobe measures all layers in parallel and shows deltas:

Layer	What is measured
ICMP	Pure network latency (ping)
TCP	TCP handshake overhead (connect)
TLS	SSL/TLS handshake — paid once per connection
HTTP cold	Full request (new connection: includes TCP + TLS)
HTTP keep-alive	Estimated without TCP/TLS — represents server processing + transfer

Note: Comparison is done on a cold connection. In production with HTTP keep-alive or HTTP/2, only the keep-alive HTTP cost applies per request.

Stability indicator

ltiprobe computes the P99/P50 ratio to assess latency consistency:

Ratio	Interpretation
< 2x	Very stable — all users have a similar experience
2x – 5x	Stable — some acceptable variation
5x – 10x	Variable — noticeable latency spikes
> 10x	Unstable — some users experience very high latency

Network hop indicator (--traceroute)

Hops	Indicator
≤ 15	Excellent — very direct route
≤ 25	Good — normal routing
≤ 35	High — long route (typically intercontinental)
> 35	Critical — suboptimal route or routing issue

Hidden hops (* * *) are counted but reported separately.

CDN / cache detection

ltiprobe automatically sends a HEAD request in parallel and reads response headers to detect whether the response comes from a CDN cache or the origin server.

CDN detected	Header analysed
Cloudflare	CF-Ray
CloudFront (AWS)	X-Amz-Cf-Pop
Fastly	X-Served-By
Akamai	X-Check-Cacheable
Varnish	Via

Multi-environment profiles (--config-file)

ltiprobe --config-file prod.yaml
ltiprobe --config-file staging.yaml

Multilingual support

Set langue: EN or langue: FR in ltiprobe.yaml.

CSV export

With --csv, ltiprobe generates a timestamped file containing columns average, min, max, p50 through p999, dns_moyenne, and hdr_encode (compressed histogram replayable with the HdrHistogram library).

License

MIT

---

Français

Outil de mesure de latence HTTP/DNS/ICMP/TCP/TLS avec validation de SLOs et détection CDN. Affiche une distribution complète des latences (P50 à P99.9) depuis le Terminal.

Installation

pip install ltiprobe

Utilisation

ltiprobe                              # Sites définis dans ltiprobe.yaml
ltiprobe https://apple.com            # Site personnalisé
ltiprobe -n 20                        # 20 mesures par site
ltiprobe --csv                        # Export CSV
ltiprobe --traceroute                 # Afficher les hops réseau
ltiprobe --config-file staging.yaml   # Fichier de config alternatif

Configuration (ltiprobe.yaml)

nb_mesures: 10
timeout: 10
langue: FR        # FR ou EN

sites:
  - url: https://api.exemple.com/health
    slo:
      http_p50_ms: 200
      http_p95_ms: 400
      dns_ms: 50
    assert:
      status_code: 200
      body_contains: "ok"

Clés SLO disponibles

Clé	Description
http_p50_ms	Latence HTTP médiane (P50)
http_p95_ms	Latence HTTP P95
dns_ms	Latence DNS moyenne
tls_ms	Durée du handshake TLS
icmp_ms	Latence réseau ICMP
tcp_ms	Durée du handshake TCP
http_chaud_ms	HTTP keep-alive estimé (sans TCP/TLS)
stabilite_ratio	Ratio P99/P50
nb_hops_max	Hops réseau max (requiert --traceroute)

Licence

MIT