During network diagnostics, you might encounter the pipe value in ping output. This metric appears in the extended statistics line when using GNU ping implementations (commonly found in Linux distributions). The format typically looks like:

rtt min/avg/max/mdev = 0.091/0.343/118.051/3.605 ms, pipe 9, ipg/ewma 0.210/0.130 ms

The pipe <number> indicates the maximum number of outstanding (unanswered) ICMP echo requests during the ping test. This value helps reveal:

• Network congestion patterns
• Packet reordering events
• Buffer bloat situations

A higher pipe number suggests more packets were "in flight" simultaneously, which typically occurs when:

1. There's significant network latency
2. The round-trip time (RTT) varies substantially
3. The network path has buffering capacity

Consider these real-world examples:

# Good connection (low pipe value)
pipe 2, rtt min/avg/max = 20/22/25 ms

# Congested connection (high pipe value)  
pipe 12, rtt min/avg/max = 50/300/1200 ms

The pipe number correlates with the ratio between your ping interval and the actual RTT. You can test this relationship by adjusting ping parameters:

ping -i 0.2 example.com  # Fast interval (likely higher pipe)
ping -i 1.0 example.com  # Slower interval (likely lower pipe)

Combine pipe analysis with other tools for deeper insights:

# Monitor pipe changes during traffic shaping
ping -i 0.01 example.com | grep --line-buffered "pipe"

# Correlate with tcptraceroute
tcptraceroute example.com

Remember that pipe values are most meaningful when:

• Testing with many packets (1000+)
• Using consistent packet sizes
• Comparing against baseline measurements

This bash script logs pipe values over time:

#!/bin/bash
TARGET="example.com"
INTERVAL=0.2
COUNT=1000

ping -i $INTERVAL -c $COUNT $TARGET | \
awk '/pipe/ {print strftime("%Y-%m-%d %H:%M:%S"), $0}' > ping_pipe.log

For developers working with raw sockets, here's how you might implement similar tracking in Python:

import subprocess

def monitor_pipe_values(target, duration=60):
    cmd = f"ping -i 0.2 -w {duration} {target}"
    process = subprocess.Popen(cmd.split(), stdout=subprocess.PIPE)
    
    while True:
        output = process.stdout.readline()
        if "pipe" in str(output):
            print(f"Pipe value detected: {output}")
        if not output and process.poll() is not None:
            break

While pipe values alone don't indicate problems, consider investigating when you see:

- Sudden pipe spikes during steady-state traffic
- Pipe values exceeding 10-15 in normal conditions
- Inconsistent pipe values between identical tests

These patterns might suggest:

• Network route changes
• Bufferbloat issues
• Intermittent congestion

---

During network diagnostics, you might encounter this unusual line in your ping statistics:

rtt min/avg/max/mdev = 0.091/0.343/118.051/3.605 ms, pipe 9, ipg/ewma 0.210/0.130 ms

The pipe <number> value represents the maximum number of outstanding (unanswered) ICMP echo requests during your ping test. This metric appears when using Linux's advanced ping implementation (typically iputils or iproute2 versions).

Here's what happens under the hood:

• When you run ping with high frequency (short interval)
• The sender may transmit multiple requests before receiving replies
• The pipe counter tracks how many requests are "in flight" simultaneously

This becomes particularly relevant in scenarios like:

ping -f -i 0.01 example.com  # Flood ping with 10ms interval

Or when testing high-latency networks where response times vary significantly.

A higher pipe number indicates:

• Network congestion or latency spikes
• Possible packet reordering
• That your ping interval might be too aggressive for the network conditions

Consider this test output comparison:

# Normal ping
$ ping -c 100 example.com
...
pipe 2

# Aggressive ping
$ ping -c 100 -i 0.001 example.com
...
pipe 14

For programmers writing network-sensitive applications:

// When implementing custom ping-like functionality
// Consider tracking outstanding requests similar to pipe counter
class NetworkProbe {
    constructor() {
        this.outstandingRequests = new Map();
        this.maxPipeSize = 0;
    }

    sendProbe() {
        const id = generateId();
        this.outstandingRequests.set(id, Date.now());
        this.maxPipeSize = Math.max(
            this.maxPipeSize,
            this.outstandingRequests.size
        );
    }
}

If you consistently see high pipe numbers (like pipe 9 in your example):

1. Try increasing your ping interval (-i flag)
2. Check for network jitter with tools like mtr
3. Consider lower-level analysis with tcpdump