Overview

The Topology View provides a visual (cluster-wide) overview of the network topology controlled by ONOS. When the topology view is instantiated it requests topology information from the server; on receipt of that information, the view renders a visualization of devices, hosts, and the links between them. The view uses the web-socket connection established by the UI framework to allow the server to drive updates to the view via topology events (such as addHost, updateDevice, etc.)

Quick Help

One of the first things to note is that by pressing the slash '/' or backslash '\' key, you can bring up the Quick Help panel. This gives an outline of the keystroke commands and mouse gestures available to you in the Topology View.  Pressing either of these keys again (or pressing the Esc key) will dismiss the panel.

• The top section lists global key-bindings (available on every view in the UI)
• The middle section lists view-specific key-bindings
  • The first and second columns show general commands for the Topology view
  • The third column shows commands for the currently active "Topology Overlay" (if any)
• The bottom section lists view-specific mouse gestures and other notes

The available commands listed in this panel are described in more detail in the sections below.

Toolbar

The Topology View's key-bindings (listed in Quick Help) are also associated with buttons on the toolbar. 

The toolbar can be shown or hidden by pressing the dot (.) key.

Note: Toolbar button states (toggled on or off) are persisted in user preferences, so may appear differently to those shown.

The toolbar has three rows of buttons:

• The first row and half the second row provide basic functions.
• The second half of the second row provides a radio-button-set of installed "overlays".
• The third row contains buttons contributed by the currently-active "overlay".

Hovering the mouse over a button will display a tooltip describing the button, and showing the bound key-stroke:

General Topology Functions

Toolbar First Row

Icon	Key	Function	Default State	Comments
	I	Show / hide ONOS cluster instance panel	show	The instance panel is shown by default.
	O	Show / hide ONOS summary panel	show	The summary panel is shown by default.
	D	Disable / enable details panel	enable	The details panel is enabled by default, and is displayed when one or more topology elements are selected. Disabling this panel keeps it hidden even when something is selected.
	H	Toggle host visibility	hide	Shows or hides the hosts (and their links). Hosts are hidden by default.
	M	Toggle offline visibility	show	Devices that are offline (but that ONOS still knows about) are shown by default. This toggle will hide offline devices (and any hosts/links connected to them).
	P	Toggle port highlighting	on	Port highlighting is when hovering the mouse over a link will highlight the link and label the ends with the appropriate port numbers. This feature can be switched off with this toggle.
	B	Toggle background map	hide	The background map (hidden by default) can be shown or hidden with this toggle.
	S	Toggle sprite layer	hide	The sprite layer (static shapes/text injected into the view) can be shown or hidden with this toggle.

Toolbar Second Row

Icon	Key	Description	Default State	Comments
	Z	Toggle oblique view (experimental)	regular view	Creates a split-level visualization of the packet and optical layers of the network. Note that this feature is experimental and may be slightly buggy.
	N	Cycle node layers	show all layers	Cycles between three view modes: show all layers, show packet layer, show optical layer.
	L	Cycle device labels	hide labels	Cycles between three modes of showing labels on devices: hide labels, show friendly labels, show device ID.
	R	Reset pan / zoom	-	This function restores the pan and zoom levels to default settings.
	E	Equalize mastership roles	-	Sends a command to ONOS to invoke a mastership equalization request.
		No overlay		De-activates the current overlay.
		Traffic overlay		Provides traffic monitoring functions.
...		...		<Topology Overlays installed by ONOS Apps will appear here>

Toolbar Third Row

The third row of the toolbar is space reserved for the currently active topology overlay.

Cluster Instance Panel

The cluster instance panel shows summary information about the ONOS instances in the cluster. There will be one box per instance, showing the instance ID, IP address, and number of switches for which the instance is master.

The panel can be hidden (and subsequently re-shown) by pressing the 'I' (for "instances") key.

The color coding indicates controller mastership; each device in the topology will be colored corresponding to which instance has mastership over it. For example:

For a clearer indication of mastership, clicking on an instance box in the instance panel will highlight the appropriate devices, subduing all else:

Click again on the same instance box (or press Esc) to cancel the affinity highlighting.

Icon	Key	Description		Icon	Key	Description
	V	Show all related intents			E	Equalize mastership roles
	Right Arrow	Show next related intent
	Left Arrow	Show previous related intent
	W	Monitor traffic of selected intent
	A	Monitor all traffic
	F	Show device link flows

Summary Panel

The summary panel shows a brief summary of properties of the network.

The panel can be hidden (and subsequently re-shown) by pressing the 'O' key.

Nodes and Links

The network topology is represented by an undirected graph of nodes and links. The nodes represent devices (switches) and hosts; the links represent, uh, links.

The D3 Force Layout algorithm is used to provide a reasonable initial layout of the nodes and links in the absence of any other spatial information. As an example, the following image shows a (free-floating) network of 25 nodes:

The onos-topo-cfg command (script) can be used to upload topology meta-data to the server. This may include longitude/latitude information for each of the nodes. 

cd ~/onos-next/tools/test/topos

onos-topo-cfg localhost attmpls.json

On receipt of the data, the server sends node updates to the GUI. On the GUI side, the longitude/latitude data is used to calibrate node positions with the background map:

Note that, by default, hosts are hidden. Pressing the 'H' key will toggle the host visibility:

Additionally, pressing the 'L' key will cycle through the devices labels ("friendly", "ID" "no-label"):

Mouse Gestures

A node (device/host) may be manually repositioned (and pinned into place) by clicking and dragging it to a new location.

NOTE: To unpin a pinned node, hover the mouse over the node and press the 'U' (Unpin) key.

Clicking on a node will select it (and deselect any other selections). Details of the selected node will appear in the details panel. Note that action buttons relating to the selection are provided at the bottom of the panel.

Multiple selections may be achieved by holding down the Shift key while clicking on a node - this toggles the selection state of that node.

Pressing the Escape key will clear the current selection. 

Panning and zooming the topology is achieved with  Cmd-drag (or Alt-drag) and Cmd-scroll (or Alt-scroll) gestures. Pressing the 'R' key will reset pan/zoom to the default values.

Details Panel

The details panel appears when something of interest is "selected". 

When a single device is selected, properties of that device are displayed, along with action buttons:

Topology View Actions		Navigation Actions
	Show Related Traffic		Show Device View for Selected Device
	Show Device Flows		Show Flow View for Selected Device
			Show Port View for Selected Device
			Show Group View for Selected Device

When multiple devices are selected, the details panel switches format to show the IDs of the selections and provides a single action button:

 Show Related Traffic

When a single host is selected, properties of that host are displayed, along with an action button:

 Show Related Traffic

When exactly two hosts are selected, their IDs are shown, along with the following action buttons:

 Show Related Traffic

 Create Host-to-Host Flow

Visualizing Traffic

A number of commands allow different visualizations of traffic on the network.

(NOTE: the section on visualizing traffic will be moved to a new page soon, once the functionality has been migrated to a "Traffic Overlay").

All Traffic

If there is traffic flowing on the network (for example, if reactive forwarding is active, and a pingall is run on mininet), then pressing the 'A' key will display something like the following:

Note that the labels on the links show the cumulative number of bytes traversing that link since traffic monitoring was requested, (i.e. since the 'A' key was pressed).

Device Link Flows

If a specific device is selected, and the 'F' key pressed, then the number of flows egressing from the device will be shown:

Host to Host Intent

The following 4 images show the selection of two hosts and the installation of a host-to-host intent:

(1) Host (.15) at Denver (DNVR) is selected:

(2) Host (.14) at Orlando (ORLD) is selected:

(3) "Create Host-to-Host Flow" action button pressed (on Detail Panel):

(4) Monitor traffic of selected intent ('W' key pressed). Note the traffic showing as labels on the links:

Show Related Intents

If a device is selected, pressing the 'V' key will show all related intents, i.e. all intents for which the selected device is a part. Note that if multiple devices are selected, a logical AND operation is applied, meaning that only those intents for which all the selected devices are a part will be highlighted.

(1) Related intent which passes through both Denver (DNVR) and Dallas (DLLS):

(2) There are no related intents that pass through Denver (DNVR), Dallas (DLLS), and Kansas City (KSCY):

A Set of Related Intents

It is quite probable that a device will be associated with a set of intents. For our example here, let's set up two more host-to-host intents that pass through Dallas:

(1) From host (.13) at Dallas (DLLS) to host (.9) at St Louis (STLS): 

(2) From host (.12) at San Antonio (SNAN) to host (.2) at Chicago (CHCG):

Clearing the selection, then selecting the Dallas device and pressing the 'V' key, we can see the related intents:

Now, by repeatedly pressing the Right-Arrow key (for next-related-intent) or Left-Arrow key (for previous-related-intent), we can step through the intents one at a time. Notice how one intent will be highlighted in orange (the primary selection) and all the other (related) intents are highlighted in green (the secondary selection):

(1) Press '→' key

(2) Press '→' key

(3) Press '→' key

ONOS Instance Failover

The GUI is designed to detect when the Cluster Instance to which it is connected fails, and to seamlessly "failover" to an alternate cluster member.

(1) Note the three instances, each master of a number of switches (8, 8, and 9, respectively). Note also that the UI is attached to the first instance, as indicated by the icon:

(2) Here, the first instance has failed and the UI has switched over to the second instance. Note also that the remaining two instances have picked up mastership of the switches (now, 9, and 16 respectively):

(3) When the first instance recovers it comes back online, but note how the UI remains attached to the second instance, and also that there is no automatic re-balancing of switch mastership. (now, 0, 9, and 16, respectively):

(4) Pressing the 'E' key sends a command to the server to "Equalize" the mastership roles across the cluster. Note now how the switches have been rebalanced, (now 8, 9, and 8, respectively):

Miscellaneous Controls

The remaining keystrokes are: 

• M - Toggle offline device visibility
  • Normally, offline devices are shown as grayed-out icons. This can be toggled to where offline devices are hidden instead.
• B - Toggle background image
  • The map of the Continental US can be toggled off and on.
• S - Toggle sprite layer
  • The sprite layer (with injected sprites) can be toggled on and off.
• X - Lock / unlock node positions
  • The default is to allow click-and-drag to move nodes (devices & hosts) on the display. 
• Z - Toggle oblique view (Experimental)
  • This mode will show a "sideways" view of the network, separating packet-layer nodes from optical-layer nodes.
  • As noted, this mode is currently experimental.

Topology Overlay Components

An ONOS application can provide a Topology Overlay Component to inject additional detail and behavior to the topology view.

Background Map

The background map provides a geographic reference for the topology. The default map is the Continental US. The map layer's visibility can be toggled on and off with the 'B' (for background) key.

See Providing Alternate Maps for the Topology View for additional details.

Custom Sprites

The Topology Sprite Layer mechanism allows custom "background" elements to be displayed (above the background map, but below the topology elements). This could be used, for example, to inject labeled "subnet clouds", or the plan of an office building or campus into the topology view. Typically, one would want to hide the background map layer (press 'B') and show the sprite layer (press 'S') instead.

In the current release (1.3.0 "Cardinal") sprite layers are defined in an external JSON format and uploaded to the controller via a REST command. They are loaded into the Topology view by manually adjusting the browser URL to include a "sprites" query parameter. We hope to provide a more user-friendly mechanism (directly through the GUI) in some future release.