Application-Layer Traffic Optimization (ALTO) Protocol
- Created
- 2014-03-18
- Last Updated
- 2023-08-14
- Available Formats
-

XML
HTML
Plain text
Registries Included Below
- ALTO Cost Modes
- ALTO Cost Metrics
- ALTO Cost Source Types
- ALTO Endpoint Property Types
- ALTO Address Types
- ALTO Error Codes
- ALTO Entity Domain Types
- ALTO Entity Property Types
ALTO Cost Modes
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC9274]
- Note
-
Identifiers prefixed with "priv:" are reserved for Private Use (see [RFC9274], Section 5). - Available Formats
-

CSV
| Identifier | Description | Intended Semantics | Reference |
|---|---|---|---|
| numerical | Indicates that numerical operations can be performed on the returned costs | Section 6.1.2.1 of [RFC7285] | [RFC9274] |
| ordinal | Indicates that the cost values in a cost map represent ranking | Section 6.1.2.2 of [RFC7285] | [RFC9274] |
| array | Indicates that the cost value is a JSON array | Section 6.5.2 of [RFC9275] | [RFC9275] |
ALTO Cost Metrics
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC7285][RFC Errata 6874]
- Note
-
Identifiers prefixed with "priv:" are reserved for Private Use (see [RFC7285], Section 10.6). - Available Formats
-

CSV
| Identifier | Intended Semantics | Reference |
|---|---|---|
| routingcost | See Section 6.1.1.1 of [RFC7285] | [RFC7285] |
| delay-ow | See Section 4.1 of [RFC9439] | [RFC9439] |
| delay-rt | See Section 4.2 of [RFC9439] | [RFC9439] |
| delay-variation | See Section 4.3 of [RFC9439] | [RFC9439] |
| lossrate | See Section 4.4 of [RFC9439] | [RFC9439] |
| hopcount | See Section 4.5 of [RFC9439] | [RFC9439] |
| tput | See Section 5.1 of [RFC9439] | [RFC9439] |
| bw-residual | See Section 5.2 of [RFC9439] | [RFC9439] |
| bw-available | See Section 5.3 of [RFC9439] | [RFC9439] |
| ane-path | See Section 6.5.1 of [RFC9275] | [RFC9275] |
ALTO Cost Source Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC9439]
- Available Formats
-

CSV
| Identifier | Intended Semantics | Reference |
|---|---|---|
| nominal | Values in nominal cases (Section 3.1 of [RFC9439]) | [RFC9439] |
| sla | Values reflecting service level agreement (Section 3.1 of [RFC9439]) | [RFC9439] |
| estimation | Values by estimation (Section 3.1 of [RFC9439]) | [RFC9439] |
ALTO Endpoint Property Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC7285][RFC Errata 6876]
- Note
-
Identifiers prefixed with "priv:" are reserved for Private Use (see [RFC7285], Section 10.8.2). - Available Formats
-

CSV
| Identifier | Intended Semantics | Reference |
|---|---|---|
| pid | See Section 7.1.1 of [RFC7285] | [RFC7285] |
ALTO Address Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC7285]
- Available Formats
-

CSV
| Identifier | Address Encoding | Prefix Encoding | Mapping to/from IPv4/v6 | Reference |
|---|---|---|---|---|
| ipv4 | See Section 10.4.3 of [RFC7285] | See Section 10.4.3 of [RFC7285] | Direct mapping to IPv4 | [RFC7285] |
| ipv6 | See Section 10.4.3 of [RFC7285] | See Section 10.4.3 of [RFC7285] | Direct mapping to IPv6 | [RFC7285] |
ALTO Error Codes
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC7285]
- Available Formats
-

CSV
| Error Code | Intended Usage | Reference |
|---|---|---|
| E_SYNTAX | Parsing error in request (including identifiers). See Section 8.5.2 of [RFC7285] | [RFC7285] |
| E_MISSING_FIELD | A required JSON field is missing. See Section 8.5.2 of [RFC7285] | [RFC7285] |
| E_INVALID_FIELD_TYPE | The type of the value of a JSON field is invalid. See Section 8.5.2 of [RFC7285] | [RFC7285] |
| E_INVALID_FIELD_VALUE | The value of a JSON field is invalid. See Section 8.5.2 of [RFC7285] | [RFC7285] |
ALTO Entity Domain Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC9240]
- Available Formats
-

CSV
| Identifier | Entity Identifier Encoding | Hierarchy and Inheritance | Media Type of Defining Resource | Mapping to ALTO Address Type | Reference |
|---|---|---|---|---|---|
| ipv4 | See [RFC9240], Section 6.1.1 | See [RFC9240], Section 6.1.3 | application/alto-networkmap+json | true | [RFC9240] |
| ipv6 | See [RFC9240], Section 6.1.2 | See [RFC9240], Section 6.1.3 | application/alto-networkmap+json | true | [RFC9240] |
| pid | See [RFC9240], Section 6.2 | None | application/alto-networkmap+json | false | [RFC9240] |
| asn | See [RFC9241], Section 6.1.1.2 | None | None | false | [RFC9241] |
| countrycode | See [RFC9241], Section 6.1.2.2 | None | None | false | [RFC9241] |
| ane | See [RFC9275], Section 6.2.2 | None | application/alto-propmap+json | false | [RFC9275] |
| subdivisioncode | See [RFC9388], Section 3.1.2 | None | None | false | [RFC9388] |
ALTO Entity Property Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC9240]
- Available Formats
-

CSV
| Identifier | Intended Semantics | Media Type of Defining Resource | Reference |
|---|---|---|---|
| pid | See [RFC7285], Section 7.1.1 | application/alto-networkmap+json | [RFC9240] |
| cdni-capabilities | See [RFC9241], Section 6.2 | application/alto-cdni+json | [RFC9241] |
| max-reservable-bandwidth | See [RFC9275], Section 6.4.1 | application/alto-propmap+json | [RFC9275] |
| persistent-entity-id | See [RFC9275], Section 6.4.2 | application/alto-propmap+json | [RFC9275] |