Status: Experimental
The attributes described in this section are not specific to a particular operation but rather generic. They may be used in any Span they apply to. Particular operations may refer to or require some of these attributes.
- Server, client and shared network attributes
- General remote service attributes
- General identity attributes
- General thread attributes
- Source Code Attributes
These attributes may be used to describe the client and server in a connection-based network interaction where there is one side that initiates the connection (the client is the side that initiates the connection). This covers all TCP network interactions since TCP is connection-based and one side initiates the connection (an exception is made for peer-to-peer communication over TCP where the "user-facing" surface of the protocol / API does not expose a clear notion of client and server). This also covers UDP network interactions where one side initiates the interaction, e.g. QUIC (HTTP/3) and DNS.
In an ideal situation, not accounting for proxies, multiple IP addresses or host names,
the server.* attributes are the same on the client and server.
For all IP-based protocols, the "address" should be just the IP-level address.
Protocol-specific parts of an address are split into other attributes (when applicable) such as "port" attributes for
TCP and UDP. If such transport-specific information is collected and the attribute name does not already uniquely
identify the transport, then setting network.transport is especially encouraged.
Warning Attributes in this section are in use by the HTTP semantic conventions. Once the HTTP semantic conventions are declared stable, changes to the attributes in this section will only be allowed if they do not cause breaking changes to HTTP semantic conventions.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
server.address |
string | Server domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1] | example.com; 10.1.2.80; /tmp/my.sock |
Recommended |
server.port |
int | Server port number. [2] | 80; 8080; 443 |
Recommended |
[1]: When observed from the client side, and when communicating through an intermediary, server.address SHOULD represent the server address behind any intermediaries, for example proxies, if it's available.
[2]: When observed from the client side, and when communicating through an intermediary, server.port SHOULD represent the server port behind any intermediaries, for example proxies, if it's available.
server.address and server.port represent logical server name and port. Semantic conventions that refer to these attributes SHOULD
specify what these attributes mean in their context.
For IP-based communication, the name should be a DNS host name of the service. On client side it matches remote service name, on server side, it represents local service name as seen externally on clients.
When connecting to an URL https://example.com/foo, server.address matches "example.com" on both client and server side.
On client side, it's usually passed in form of URL, connection string, host name, etc. Sometimes host name is only available to instrumentation as a string which may contain DNS name or IP address. server.address SHOULD be set to the available known hostname (e.g., "127.0.0.1" if connecting to an URL https://127.0.0.1/foo).
If only IP address is available, it should be populated on server.address. Reverse DNS lookup SHOULD NOT be used to obtain DNS name.
If network.transport is "pipe", the absolute path to the file representing it should be used as server.address.
If there is no such file (e.g., anonymous pipe),
the name should explicitly be set to the empty string to distinguish it from the case where the name is just unknown or not covered by the instrumentation.
For Unix domain socket, server.address attribute represents remote endpoint address on the client side and local endpoint address on the server side.
Warning Attributes in this section are in use by the HTTP semantic conventions. Once the HTTP semantic conventions are declared stable, changes to the attributes in this section will only be allowed if they do not cause breaking changes to HTTP semantic conventions.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
client.address |
string | Client address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1] | client.example.com; 10.1.2.80; /tmp/my.sock |
Recommended |
client.port |
int | Client port number. [2] | 65123 |
Recommended |
[1]: When observed from the server side, and when communicating through an intermediary, client.address SHOULD represent the client address behind any intermediaries, for example proxies, if it's available.
[2]: When observed from the server side, and when communicating through an intermediary, client.port SHOULD represent the client port behind any intermediaries, for example proxies, if it's available.
These attributes may be used to describe the sender and receiver of a network exchange/packet. These should be used when there is no client/server relationship between the two sides, or when that relationship is unknown. This covers low-level network interactions (e.g. packet tracing) where you don't know if there was a connection or which side initiated it. This also covers unidirectional UDP flows and peer-to-peer communication where the "user-facing" surface of the protocol / API does not expose a clear notion of client and server.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
source.address |
string | Source address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1] | source.example.com; 10.1.2.80; /tmp/my.sock |
Recommended |
source.port |
int | Source port number | 3389; 2888 |
Recommended |
[1]: When observed from the destination side, and when communicating through an intermediary, source.address SHOULD represent the source address behind any intermediaries, for example proxies, if it's available.
Destination fields capture details about the receiver of a network exchange/packet.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
destination.address |
string | Destination address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1] | destination.example.com; 10.1.2.80; /tmp/my.sock |
Recommended |
destination.port |
int | Destination port number | 3389; 2888 |
Recommended |
[1]: When observed from the source side, and when communicating through an intermediary, destination.address SHOULD represent the destination address behind any intermediaries, for example proxies, if it's available.
Warning Attributes in this section are in use by the HTTP semantic conventions. Once the HTTP semantic conventions are declared stable, changes to the attributes in this section will only be allowed if they do not cause breaking changes to HTTP semantic conventions.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
network.local.address |
string | Local address of the network connection - IP address or Unix domain socket name. | 10.1.2.80; /tmp/my.sock |
Recommended |
network.local.port |
int | Local port number of the network connection. | 65123 |
Recommended |
network.peer.address |
string | Peer address of the network connection - IP address or Unix domain socket name. | 10.1.2.80; /tmp/my.sock |
Recommended |
network.peer.port |
int | Peer port number of the network connection. | 65123 |
Recommended |
network.protocol.name |
string | OSI application layer or non-OSI equivalent. [1] | amqp; http; mqtt |
Recommended |
network.protocol.version |
string | Version of the protocol specified in network.protocol.name. [2] |
3.1.1 |
Recommended |
network.transport |
string | OSI transport layer or inter-process communication method. [3] | tcp; udp |
Recommended |
network.type |
string | OSI network layer or non-OSI equivalent. [4] | ipv4; ipv6 |
Recommended |
[1]: The value SHOULD be normalized to lowercase.
[2]: network.protocol.version refers to the version of the protocol used and might be different from the protocol client's version. If the HTTP client has a version of 0.27.2, but sends HTTP version 1.1, this attribute should be set to 1.1.
[3]: The value SHOULD be normalized to lowercase.
Consider always setting the transport when setting a port number, since a port number is ambiguous without knowing the transport. For example different processes could be listening on TCP port 12345 and UDP port 12345.
[4]: The value SHOULD be normalized to lowercase.
network.transport has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.
| Value | Description |
|---|---|
tcp |
TCP |
udp |
UDP |
pipe |
Named or anonymous pipe. |
unix |
Unix domain socket |
network.type has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.
| Value | Description |
|---|---|
ipv4 |
IPv4 |
ipv6 |
IPv6 |
These attributes identify network peers that are directly connected to each other.
network.peer.address and network.local.address should be IP addresses, Unix domain socket names, or other addresses specific to network type.
Note: Specific structures and methods to obtain socket-level attributes are mentioned here only as examples. Instrumentations would usually use Socket API provided by their environment or sockets implementations.
When connecting using connect(2) (Linux or other POSIX systems /
Windows)
or bind(2)(Linux or other POSIX systems /
Windows)
with AF_INET address family, network.peer.address and network.peer.port represent sin_addr and sin_port fields
of sockaddr_in structure.
network.peer.address and network.peer.port can be obtained by calling getpeername method
(Linux or other POSIX systems /
Windows).
network.local.address and network.local.port can be obtained by calling getsockname method
(Linux or other POSIX systems /
Windows).
Note that network.local.* attributes are not included in these examples since they are typically Opt-In.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
network.carrier.icc |
string | The ISO 3166-1 alpha-2 2-character country code associated with the mobile carrier network. | DE |
Recommended |
network.carrier.mcc |
string | The mobile carrier country code. | 310 |
Recommended |
network.carrier.mnc |
string | The mobile carrier network code. | 001 |
Recommended |
network.carrier.name |
string | The name of the mobile carrier. | sprint |
Recommended |
network.connection.subtype |
string | This describes more details regarding the connection.type. It may be the type of cell technology connection, but it could be used for describing details about a wifi connection. | LTE |
Recommended |
network.connection.type |
string | The internet connection type. | wifi |
Recommended |
network.connection.subtype has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.
| Value | Description |
|---|---|
gprs |
GPRS |
edge |
EDGE |
umts |
UMTS |
cdma |
CDMA |
evdo_0 |
EVDO Rel. 0 |
evdo_a |
EVDO Rev. A |
cdma2000_1xrtt |
CDMA2000 1XRTT |
hsdpa |
HSDPA |
hsupa |
HSUPA |
hspa |
HSPA |
iden |
IDEN |
evdo_b |
EVDO Rev. B |
lte |
LTE |
ehrpd |
EHRPD |
hspap |
HSPAP |
gsm |
GSM |
td_scdma |
TD-SCDMA |
iwlan |
IWLAN |
nr |
5G NR (New Radio) |
nrnsa |
5G NRNSA (New Radio Non-Standalone) |
lte_ca |
LTE CA |
network.connection.type has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.
| Value | Description |
|---|---|
wifi |
wifi |
wired |
wired |
cell |
cell |
unavailable |
unavailable |
unknown |
unknown |
For Unix and pipe, since the connection goes over the file system instead of being directly to a known peer, server.address is the only attribute that usually makes sense (see description of server.address below).
This attribute may be used for any operation that accesses some remote service. Users can define what the name of a service is based on their particular semantics in their distributed system. Instrumentations SHOULD provide a way for users to configure this name.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
peer.service |
string | The service.name of the remote service. SHOULD be equal to the actual service.name resource attribute of the remote service if any. |
AuthTokenCache |
Recommended |
Examples of peer.service that users may specify:
- A Redis cache of auth tokens as
peer.service="AuthTokenCache". - A gRPC service
rpc.service="io.opentelemetry.AuthService"may be hosted in both a gateway,peer.service="ExternalApiService"and a backend,peer.service="AuthService".
These attributes may be used for any operation with an authenticated and/or authorized enduser.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
enduser.id |
string | Username or client_id extracted from the access token or Authorization header in the inbound request from outside the system. | username |
Recommended |
enduser.role |
string | Actual/assumed role the client is making the request under extracted from token or application security context. | admin |
Recommended |
enduser.scope |
string | Scopes or granted authorities the client currently possesses extracted from token or application security context. The value would come from the scope associated with an OAuth 2.0 Access Token or an attribute value in a SAML 2.0 Assertion. | read:message, write:files |
Recommended |
These attributes describe the authenticated user driving the user agent making requests to the instrumented system. It is expected this information would be propagated unchanged from node-to-node within the system using the Baggage mechanism. These attributes should not be used to record system-to-system authentication attributes.
Examples of where the enduser.id value is extracted from:
| Authentication protocol | Field or description |
|---|---|
| HTTP Basic/Digest Authentication | username |
| OAuth 2.0 Bearer Token | OAuth 2.0 Client Identifier value from client_id for the OAuth 2.0 Client Credentials Grant flow and subject or username from get token info response for other flows using opaque tokens. |
| OpenID Connect 1.0 IDToken | sub |
| SAML 2.0 Assertion | urn:oasis:names:tc:SAML:2.0:assertion:Subject |
| Kerberos | PrincipalName |
| Framework | Field or description |
|---|---|
| JavaEE/JakartaEE Servlet | javax.servlet.http.HttpServletRequest.getUserPrincipal() |
| Windows Communication Foundation | ServiceSecurityContext.Current.PrimaryIdentity |
Given the sensitive nature of this information, SDKs and exporters SHOULD drop these attributes by default and then provide a configuration parameter to turn on retention for use cases where the information is required and would not violate any policies or regulations.
These attributes may be used for any operation to store information about a thread that started a span.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
thread.id |
int | Current "managed" thread ID (as opposed to OS thread ID). | 42 |
Recommended |
thread.name |
string | Current thread name. | main |
Recommended |
Examples of where thread.id and thread.name can be extracted from:
| Language or platform | thread.id |
thread.name |
|---|---|---|
| JVM | Thread.currentThread().getId() |
Thread.currentThread().getName() |
| .NET | Thread.CurrentThread.ManagedThreadId |
Thread.CurrentThread.Name |
| Python | threading.current_thread().ident |
threading.current_thread().name |
| Ruby | Thread.current.object_id |
Thread.current.name |
| C++ | std::this_thread::get_id() |
|
| Erlang | erlang:system_info(scheduler_id) |
Often a span is closely tied to a certain unit of code that is logically responsible for handling the operation that the span describes (usually the method that starts the span). For an HTTP server span, this would be the function that handles the incoming request, for example. The attributes listed below allow to report this unit of code and therefore to provide more context about the span.
| Attribute | Type | Description | Examples | Requirement Level |
|---|---|---|---|---|
code.column |
int | The column number in code.filepath best representing the operation. It SHOULD point within the code unit named in code.function. |
16 |
Recommended |
code.filepath |
string | The source code file name that identifies the code unit as uniquely as possible (preferably an absolute file path). | /usr/local/MyApplication/content_root/app/index.php |
Recommended |
code.function |
string | The method or function name, or equivalent (usually rightmost part of the code unit's name). | serveRequest |
Recommended |
code.lineno |
int | The line number in code.filepath best representing the operation. It SHOULD point within the code unit named in code.function. |
42 |
Recommended |
code.namespace |
string | The "namespace" within which code.function is defined. Usually the qualified class or module name, such that code.namespace + some separator + code.function form a unique identifier for the code unit. |
com.example.MyHttpService |
Recommended |