General Metrics

The general metrics used in Kentik queries are discussed in the following topics:

Notes:
- The categorization of metrics in the topics below corresponds to the categories by which they are grouped in the Metrics dialog (see Metrics Dialog UI).
- For general information about metrics in Kentik, see About Metrics.
- For metrics that aren't transmitted via a flow protocol, see Non-flow Metrics.
- For metrics that are device-specific, see Device-specific Metrics.
- Metrics that are available as filter or group-by dimensions are covered in the KB's Dimensions Reference (see Per-flow Metrics).
- In addition to being used for query settings in the Kentik portal, metrics are also used for the Query API.

 

About General Metrics

In Kentik, general metrics are those transmitted via flow protocols like NetFlow or sFlow. They are not tied to specific devices, such as particular router models. The availability of these metrics 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. This enables host-only metrics, which are detailed in the following topics:

 
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Host Metrics by Protocol

As shown in the table below, the availability of a given metric varies depending on the 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).

 
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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.
 
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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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