User Commands NAM(1)
NAME
nam - VINT/LBL Network Animator
SYNOPSIS
nam [ -g geometry ] [ -t graphInput ][ -i interval ] [ -P
peerName ] [ -N appName ] [ -c cacheSize ] [ -f configfile ]
[ -S ] tracefile
DESCRIPTION
Nam is a Tcl/TK based animation tool for viewing network
simulation traces and real world packet trace data.
The first step to use nam is to produce the trace file. The
trace file should contain topology information, e.g., nodes,
links, as well as packet traces. The detailed format is
described in the TRACE FILE section. Usually, the trace file
is generated by ns(1). During an ns simulation, user can
produce topology configurations, layout information, and
packet traces using tracing events in ns. Refer to ns(1) for
detailed information.
When the trace file is generated, it is ready to be animated
by nam. Upon startup, nam will read the trace file, create
topology, pop up a window, do layout if necessary, then
pause at the time of the first packet in the trace file.
Through its user interface, nam provides control over many
aspects of animation. These functionalities will be
described in detail in the USER INTERFACE section.
This version of nam is highly experimental - there will be
bugs!. Please mail ns-developers@mash.cs.berkeley.edu if you
encounter any bugs, or with suggestions for desired func-
tionality.
OPTIONS
-g Specify geometry of the window upon startup. The format
is described in X(1)
-t [Information incomplete] Instruct nam to use tkgraph,
and specify input file nam for tkgraph.
-i [Information for this option may not be accurate]
Specify rate (real) milliseconds as the screen update
rate. The default rate is 50ms (i.e., 20 frames per
second). Note that the X server may not be able to
keep up with this rate, in which case the animation
will run as fast as the X server allows it to (at 100%
cpu utilization).
-N Specify the application name of this nam instance. This
application name may later be used in peer synchroniza-
tion.
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User Commands NAM(1)
-P Specify the application name of the peer nam instance
whose execution will be synchronized with the execution
of this nam instance. Refer to the above option (-N) as
how to specify application names.
General usage is: (1) starting the first nam instance
(slave) by:
nam -N <name #1> <trace file name #1>
Then start the second nam instance (which will be the
master):
nam -N <name #2> <trace file name #2>
Then every animation control (play, stop, backward, but
exclude other inspection and interactive operations
such as monitoring) will be synchronized between the
two instances.
Please note that because this mechanism uses Tcl's send
command, it requires that your X server used xauth as
authentication. Specifically, you should add option `-
auth <authorization file name rel='nofollow' onclick='return false;'>' when you starts your X
server. Without this option, X will use xhost as
authentication, which is too weak and considered
insecure. Refer to man page of Xsecurity, xauth and
Xserver for details, and the available authentication
protocols.
-c [Information incomplete] The maximum size of the cache
used to store 'active' objects when doing backward ani-
mation.
-f Name of the initialization files to be loaded during
startup. In this file, user can define functions which
will be called in the trace file. An example for this
is the 'link-up' and 'link-down' events of dynamic
links in ns. (Refer to $ns rtmodel for detail, and
tcl/ex/simple-dyn.tcl in your ns directory for exam-
ple). Example initialization files can be found at
ex/sample.nam.tcl and ex/dynamic-nam.conf.
-S Enable synchronous X behavior so it is easier for
graphics debugging. For UNIX system running X only.
tracefile is the name of the file containing the trace data
to be animated (format described in TRACE FILE section
below). If tracefile cannot be read, nam will try to open
tracefile.nam.
OBJECTS IN NAM
nam does animation using the following building blocks:
node, link, queue, packet, agent, monitor. They are defined
below:
node Nodes are created from 'n' trace event in trace file.
It represents a source/host/router, etc. nam will
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User Commands NAM(1)
terminate if there are duplicate definition for the
same node. Node may have many shapes, (circle, square,
and hexagon), but once created it cannot change its
shape. Node may also have many colors, it can change
its color during animation. Refer to ns(1) for related
tracing events.
link Links are created between nodes to form a network
topology. nam links are internally simplex, but it is
invisible to the users. The trace event 'l' creates two
simplex links and other necessary setups, hence it
looks to users identical to a duplex link. Link may
have many colors, it can change its color during anima-
tion. Refer to ns(1) for related tracing events.
queue
Queue needs to be constructed in nam between two nodes.
Unlike link, nam queue is associated to a simplex link.
The trace event 'q' only creates a queue for a simplex
link. In nam, queues are visualized as stacked packets.
Packets are stacked along a line, the angle between the
line and the horizontal line can be specified in the
trace event 'q'.
packet
Packet is visualized as a block with an arrow. The
direction of the arrow shows the flow direction of the
packet. Queued packets are shown as little squares. A
packet may be dropped from a queue or a link. Dropped
packets are shown as rotating squares, and disappear at
the end of the screen. Dropped packets are not visible
during backward animation.
agent
Agents are used to separate protocol states from nodes.
They are always associated with nodes. An agent has a
name, which is a unique identifier of th agent. It is
shown as a square with its name inside, and a line link
the square to its associated node.
AUTOMATIC LAYOUT
In nam, a topology is specified by alternating node objects
with edge objects. But to display the topology in a
comprehensible way, a layout mechanism is needed. Currently
nam provides two layout methods.
First, user may specify edges' orientations. An edge orien-
tation is the angle between the edge and the horizontal
line, in the interval [0, 2*pi). During layout, nam will
honor the given edge orientations. Generally, it will first
choose a reference node, then place other nodes using edge
orientation and edge length, which is determined by link
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User Commands