General Metrics

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This article discusses general (i.e. flow) metrics used in Kentik queries.

Notes:

About General Metrics

In Kentik, general metrics are transmitted via flow protocols like NetFlow or sFlow and aren’t tied to specific devices. Their availability in settings like the Metrics Pane of the Query sidebar in Data Explorer depends on the device category (Router or Host) and the specific device type (see Supported Device Types).

Metrics from All Devices

When a query includes traffic solely from data sources (see About Data Sources) in the "Routers" category, only the following metrics are available:

Metric in portal

Variations

Calculated as...

Derived from KDE column(s)

Bits per second

Sampled at:

  • Ingress and Egress

  • Ingress

  • Egress

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

in_bytes,
out_bytes

Packets per second

Sampled at:

  • Ingress and Egress

  • Ingress

  • Egress

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

in_pkts,
out_pkts

Flows per second

N.A.

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

Based on rows per KDE main table

Source IPs

  • Unique Count

  • Bitrate per IP

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

inet_src_addr

Destination IPs

  • Unique Count

  • Bitrate per IP

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

inet_dst_addr

Unique Route Prefixes

  • Source

  • Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

inet_src_route_prefix,
inet_dst_route_prefix

Unique Ports

  • Source

  • Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

inet_src_route_prefix,
inet_dst_route_prefix

Unique ASNs

  • Source

  • Destination

  • Next Hop Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

src_as,
dst_as,
i_dst_nexthop_as_name

Unique Countries

  • Source

  • Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

src_geo,
dst_geo

Unique Regions

  • Source

  • Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

src_geo_region,
dst_geo_region

Unique Cities

  • Source

  • Destination

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

src_geo_city,
dst_geo_city

Sample rate

  • Max

  • Average

  • Average

  • 95th Percentile

  • 99th Percentile

  • Max

  • Total

sample_rate

Notes:

  • The “Total” metric is available only when the chart type is set to Table or Matrix (see Chart View Types).

  • Metrics labeled as "unique" are evaluated across all instances on queried devices within each individual time slice of the query's time range, but not between different time slices (see Table Time-slicing).

Host Traffic Metrics

When querying traffic that includes devices in the "Host" category (using Kentik’s host agent, see About the Universal Agent), the data from these hosts is stored in KDE.

Host Metrics by Protocol

The availability of a given metric varies by protocol:

Metric in portal

TCP

HTTP

DNS

Calculated as...

Derived from KDE column(s)

Retransmits

  • Per second

  • Repeated per second

  • Percent

  • Percent Repeated

  • Repeated Retransmits

  • Retransmitted Packets Out

N.A.

  • Average

  • Percentile (95th or 98th)

  • Max

  • Total

retransmitted_out_pkts, repeated_retransmits,
both_pkts (for %)

Out-of-order packets

  • Per second

  • Percent

  • Per second (In)

N.A.

  • Average

  • Percentile (95th or 98th)

  • Max

  • Total

ooorder_in_pkts,
ooorder_out_pkts,
both_pkts (for %)

Fragments

  • Per second

  • Percent

  • Per second

  • Per second

  • Average

  • Percentile (95th or 98th)

  • Max

  • Total

fragments,
both_pkts (for %)

Zero Windows

  • Count

  • Percent

  • Per second

N.A.

  • Average

  • Percentile (95th or 98th)

  • Max

zero_windows

Receive Window

N.A.

N.A.

N.A.

  • Average

  • Percentile (95th or 98th)

  • Max

receive_window

Latency

  • Client

  • Server

  • Application

  • First Payload Exchange

  • Client

  • Server

  • Application

  • FPEX

  • Application

  • Average

  • Percentile (95th or 98th)

  • Max

client_nw_latency_ms,
server_nw_latency_ms,
appl_latency_ms,
fpex_latency_ms

Note: The “Total” metric is available only when the chart type is set to Table or Matrix (see Chart View Types).

Host Metrics Descriptions

The following descriptions apply to the host-only metrics listed in the table above:

  • Retransmits: Packets re-sent from source to destination, applicable to reliable protocols like TCP.

    • Indicates network delivery issues affecting performance.

    • Measured per second and  as a percentage of all packets sent.

      Note: "Repeated" refers to packets retransmitted 3 or more times.

  • Out of order: Packets arriving out of sequence.

    • High values suggest variability in delivery paths, impacting latency-sensitive traffic like real-time audio/video.

    • Measured per second and  as a percentage of all packets sent.

  • Fragments/second: Packets split into smaller packets for network delivery.

    • Fragmentation can increase CPU load and cause retransmits if fragments arrive out-of-order.

    • Measured per second and as a percentage of all packets sent.

  • Zero Windows: Count of TCP receive windows with a value of zero, indicating a full buffer.

  • Receive Window: Size of the TCP receive window.

  • Latency: Various measures include:

    • RTT/2 client latency (derived): One-way latency from the client perspective. High values indicate network or server-side issues

    • RTT/2 server latency (derived): One-way latency from the server perspective. High values indicate network or client-side issues.

    • RTT/2 application latency (derived): Derived from request/response pairs at the application layer, indicating end-user experience latency. Effective for protocols with clear request/response pairings.

    • First Payload Exchange Latency: Measures application response time when the protocol isn't understood or can’t be decoded (e.g., HTTPS, SQL). Excludes TCP setup, starting with the first packet sent and ending with the first packet returned.

Host Metrics KDE Columns

The following table shows the correspondence between the metrics described above and the columns of the Kentik Data Engine (KDE):

Metric in portal

Type:
value
column

Derived from KDE column(s)

Retransmits

bigint
Native

retransmitted_out_pkts, repeated_retransmits,
both_pkts (for %)

Out-of-order packets

bigint
Native

ooorder_in_pkts,
ooorder_out_pkts,
both_pkts (for %)

Fragments

bigint
Native

fragments,
both_pkts (for %)

Zero Windows

bigint
Native

zero_windows

Receive Window

bigint
Native

receive_window

Latency

bigint
Native

client_nw_latency_ms,
server_nw_latency_ms,
appl_latency_ms,
fpex_latency_ms

Application Decodes Metrics

When using Kentik's software host agent for application decodes (see About Application Decodes), both dimensions and metrics are generated and stored in or derived from KDE columns. The metrics available for queries via the metric selector (see Metrics Dialog UI) include:

Metric in portal

Description

Type:
value
column

Connection Name

TCP connection ID.

bigint
UDR

Application Latency

One-way network latency derived by examining request/response pairs at the application layer.

bigint
UDR

FPEX Latency

Elapsed time from first packet sent to first packet returned.

bigint
UDR

Note: For dimensions related to application decodes, see Application Decodes Dimensions.

Legacy Application Decodes Metrics

The "legacy" metrics in the table below are from older versions (<v1.3.0) of Kentik’s legacy host software agent, kprobe:

Metric in portal

Description

Type:
value
column

KDE name(s)

Connection ID

TCP connection ID.

Note: Superseded by Connection Name.

bigint
Native

connection_id

Application Latency (ms)

One-way network latency derived by examining request/response pairs at the application layer.

bigint
Native

appl_latency_ms

First Payload Exchange Latency (ms)

Elapsed time from first packet sent to first packet returned.

Note: Superseded by FPEX Latency.

bigint
Native

fpex_latency_ms


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