FaceMgmt » History » Revision 25
Revision 24 (Alex Afanasyev, 03/20/2014 05:22 PM) → Revision 25/118 (Junxiao Shi, 03/24/2014 10:03 AM)
# Face Management
**Face Management** is a module of [[Management|NFD Management protocol]].
It provides:
* commands to create and destroy faces
* commands to enable and disable [[LocalControlHeader]] features on a face
* a dataset of description of all active faces and their counters
* a notification stream for face creating and destroying events
Face Management commands, datasets, and notifications are published in namespace `ndn:/localhost/nfd/faces`.
## FaceUri
A FaceUri indicates the underlying protocol and underlying address of a Face.
### UDP unicast
`udp[4|6]://<remote-IP-or-host>[:<remote-port>]`
Examples:
* `udp4://192.0.2.1:6363` (canonical form)
* `udp6://[2001:db8::1]:6363` (canonical form)
* `udp://192.0.2.1` (remote-port defaults to 6363)
* `udp://example.net:6363`
* `udp4://example.net:6363` (resolve hostname to IPv4 address only)
* `udp6://example.net:6363` (resolve hostname to IPv6 address only)
### UDP multicast
`udp-mcast://<multicast-IP>:<multicast-port>`
Examples:
* `udp://224.0.23.170:56363`
### TCP
`tcp[4|6]://<remote-IP-or-host>[:<remote-port>]`
Examples:
* `tcp4://192.0.2.1:6363` (canonical form)
* `tcp6://[2001:db8::1]:6363` (canonical form)
* `tcp://192.0.2.1` (remote-port defaults to 6363)
* `tcp://example.net:6363`
* `tcp4://example.net:6363` (resolve hostname to IPv4 address only)
* `tcp6://example.net:6363` (resolve hostname to IPv6 address only)
### UNIX stream
`unix://<path>`
Examples:
* `unix:///var/run/nfd.sock` (note there are three forward-slashes after 'unix')
URI is available for the channel only.
Accepted UNIX stream faces do not have URI.
### Ethernet unicast
`ether://<remote-MAC>`
Examples:
* `ether://08:00:27:01:01:01`
### Ethernet multicast
`ether-mcast://<multicast-MAC>`
Examples:
* `ether-mcast://33:33:01:01:01:01`
## Control Commands
[[ControlCommand]] **management-module**: `faces`
### Create a face
**command-verb**: `create`
ControlParameters fields:
* Uri (required): a FaceUri that represents a UDP unicast tunnel or a TCP tunnel
This command allows creation of UDP unicast and TCP faces only.
If another face exists for the same underlying protocol and address, the command is considered successful, and FaceId of that face is returned.
If the command succeeds, \<Body> in ControlResponse block contains updated ControlParameters:
* FaceId
* Uri: FaceUri in canonical form - hostname is substituted with IP address, scheme name indicates either IPv4 or IPv6
### Destroy a face
**command-verb:** `destroy`
ControlParameters fields:
* FaceId (required)
If the specified face does not exist, this command does nothing, but is still considered successful.
### Enable a LocalControlHeader feature
**command-verb**: `enable-local-control`
ControlParameters fields:
* FaceId (required)
* LocalControlFeature (required): 1=IncomingFaceId, 2=NextHopFaceId
If the face doesn't exist, the command fails with code 404.
If the face is not local, the command fails with code 412.
### Disable a LocalControlHeader feature
**command-verb**: `disable-local-control`
ControlParameters fields:
* FaceId (required)
* LocalControlFeature (required): 1=IncomingFaceId, 2=NextHopFaceId
If the face doesn't exist, the command fails with code 404.
If the face is not local, the command fails with code 412.
## Face Dataset
Description and counters of all active faces are published as a [[StatusDataset|Status Dataset]] at `ndn:/localhost/nfd/faces/list`.
Each face is represented by a **FaceStatus** blocks:
FaceStatus := FACE-STATUS-TYPE TLV-LENGTH
FaceId
Uri
NInInterests
NInDatas
NOutInterests
NOutDatas
NInInterests := N-IN-INTERESTS-TYPE TLV-LENGTH
nonNegativeInteger
NInDatas := N-IN-DATAS-TYPE TLV-LENGTH
nonNegativeInteger
NOutInterests := N-OUT-INTERESTS-TYPE TLV-LENGTH
nonNegativeInteger
NOutDatas := N-OUT-DATAS-TYPE TLV-LENGTH
nonNegativeInteger
* NInInterests is the total number of incoming Interests since the face is established.
* NInDatas is the total number of incoming Datas since the face is established.
* NOutInterests is the total number of outgoing Interests since the face is established.
* NOutDatas is the total number of outgoing Datas since the face is established.
## Face Status Change Notification
Face status change events are published as a [[Notification|Notification Stream]] at `ndn:/localhost/nfd/faces/events`.
Events of all faces are sent into the same notification stream.
The Content of each notification Data packet is a `FaceEventNotification` block:
FaceEventNotification := FACE-EVENT-NOTIFICATION-TYPE TLV-LENGTH
FaceEventKind
FaceId
Uri
FaceFlags
FaceEventKind := FACE-EVENT-KIND-TYPE TLV-LENGTH
nonNegativeInteger
FaceFlags := FACE-FLAGS-TYPE TLV-LENGTH
nonNegativeInteger
**FaceEventKind** indicates the kind of event. Its possible values are:
* **1**: face is created or accepted
* **2**: face is destroyed or closed
**FaceFlags** is a bitset, providing additional information about the face. The following bits are currently defined:
* **1**: face is local
* **2**: face is created on demand - accepted (e.g., as a response to an incoming connection, instead of initiated outgoing connection connection)
## TLV-TYPE assignments
Type | Assigned value | Assigned value (hex)
------------------------------------------- | ----------------- | --------------------
FaceStatus | 128 | 0x80
NInInterests | 144 | 0x90
NInDatas | 145 | 0x91
NOutInterests | 146 | 0x92
NOutDatas | 147 | 0x93
FaceEventNotification | 192 | 0xc0
FaceEventKind | 193 | 0xc1
FaceFlags | 194 | 0xc2