NFD

# NFD FIB Management Protocol

The **FIB management protocol** allows an entity to manipulate the FIB entry.

The FIB 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/fib/<command-verb>/<command-options>/<timestamp>/<SignatureInfo>/<SignatureValue>

    \                / \                              / \                                          /

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

            \/                       \/                                      \/

    NFD Control Command       FibManager command             Signed Interest related information

    to FibManager             and command options

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

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

    FibManagementOptions ::= FIB-MANAGEMENT-OPTIONS-TYPE TLV-LENGTH

                               Name?

                               FaceId?

                               Cost?

                               Strategy?

    // Name defined in NDN-TLV spec

    FaceId               ::= FACEID-TYPE TLV-LENGTH

                               nonNegativeInteger

    Cost                 ::= COST-TYPE TLV-LENGTH

                               nonNegativeInteger

    Strategy             ::= STRATEGY-TYPE TLV-LENGTH

                               Name

### 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 ``FibManagementOptions`` 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

**FIB management protocol** protocol supports five operations:

* insert a FIB entry (command-verb: ``insert``)

* delete a FIB entry (command-verb: ``delete``)

* add a nexthop to a FIB entry (command-verb: ``add-nexthop``)

* remove a nexthop from a FIB entry (command-verb: ``remove-nexthop``)

* set the forwarding strategy for a namespace (command-verb: ``set-strategy``)

## Insert a FIB entry

**command-verb:** ``insert``

Required fields in ``FibManagementOptions`` block:

* ``Name``

If a FIB entry for Name already exists, this command does nothing, but is still considered successful.

## Delete a FIB entry

**command-verb:** ``delete``

Required fields in ``FibManagementOptions`` block:

* ``Name``

If a FIB entry for Name does not exist, this command does nothing, but is still considered successful.

## Add a nexthop

**command-verb:** ``add-nexthop``

This command adds a nexthop to an existing FIB entry.

Required fields in ``FibManagementOptions`` block:

* ``Name``

* ``FaceId``

* ``Cost``

If a nexthop of same ``FaceId`` exists on the FIB entry, its cost is updated.

**FaceId** is the FaceId returned in [[FaceMgmt|NFD Face Management protocol]].

If **FaceId** is set to zero, it is implied as the face of the entity sending this command.

If the FIB entry does not exist, the response has StatusCode 404.

## Remove a nexthop

**command-verb**: ``remove-nexthop``

This command removes a nexthop from a FIB entry.

Removing the last nexthop in a FIB entry will not automatically delete the FIB entry.

Required fields in ``FibManagementOptions`` block:

* ``Name``

* ``FaceId``

**FaceId** is the FaceId returned in *NFD Face Management protocol*.

If **FaceId** is set to zero, it is implied as the face of the entity sending this command.

If the FIB entry does not exist, the response has StatusCode 404.

If the specified nexthop does not exist on the FIB entry, this command does nothing,

but is still considered successful.

## Set strategy

This command sets a forwarding strategy for a namespace.

The format of this command will be defined in a later version of this spec.

Required fields in ``FibManagementOptions`` block:

* ``Name``

* ``Strategy``

## TLV-TYPE assignments

Type                                        | Assigned value    | Assigned value (hex)

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

FibManagementOptions                        | 129               | 0x81

FaceId                                      | 130               | 0x82

Cost                                        | 131               | 0x83

Strategy                                    | 132               | 0x84