NFD

# NFD Face Management protocol

The **Face Management protocol** allows an entity to request NFD daemon create and destroy the faces.

The ace Management protocol uses [[Signed Interests]]-Data exchange.

The command request and response follows the [[ControlCommand|NFD Control Command specification]]

## Command format

### Request

Request is a signed Interest with the following name:

    /localhost/nfd/faces/<command-verb>/<command-options>/<timestamp>/<SignatureInfo>/<SignatureValue>

    \                  / \                              / \                                          /

     --------  --------   -------------  ---------------   --------------------  --------------------

             \/                        \/                                      \/

    NFD Control Command       FaceManager command            Signed Interest related information

    to FaceManager            and command options

Command options is defined as a TLV-encoded ``FaceManagementOptions`` block.

Each individual command defines a subset of required and optional elements in the ``FaceManagementOptions`` block.

    FaceManagementOptions ::= FACE-MANAGEMENT-OPTIONS-TYPE TLV-LENGTH

                               FaceId?

                               ... TBD

    // Name defined in NDN-TLV spec

    FaceId               ::= FACEID-TYPE TLV-LENGTH

                               nonNegativeInteger

### Response

Command response is a Data packet that contains TLV-encoded ``ControlResponse`` block, defined in [[ControlCommand|NFD Control Command specification]].

The response has StatusCode 200 if the command succeeds.

<!-- Alex: Should positive responses contain TLV-Encoded ``FaceManagementOptions`` block related to the command (after StatusText)? -->

Any other status code (4xx, 5xx, [?]) mean error.

Description of the error can be present in ``StatusText`` field of ``ControlResponse`` command.

### Operations

**Face management protocol** protocol supports five operations:

* create a face (command-verb: ``create``)

* destroy a face (command-verb: ``destroy``)

## Create a face

**command-verb:** ``create``

Required fields in ``FaceManagementOptions`` block:

## Destroy a face

**command-verb:** ``destroy``

Required fields in ``FaceManagementOptions`` block:

## TLV-TYPE assignments

Type                                        | Assigned value    | Assigned value (hex)

------------------------------------------- | ----------------- | --------------------

FaceManagementOptions                       | 108               | 0x6c

FaceId                                      | 105               | 0x69