Re: Solution to my multicast woes

[Lloyd Wood <L.Wood@surrey.ac.uk>]

On Mon, 14 Sep 1998, Christoph Haenle wrote:

> Hello Lloyd,
> 
> just a quick question since you seem to have dived into this matter: What 
> happens if the number of nodes exceeds 128 and "Note expandaddr" is
> activated?  Any ideas? 

[cc'd to the list as of general interest...]

AFAIK it depends on the version of ns you're running.

I seem to recall that ns 2.1b2 and earlier had no checking at all on
the number of nodes allocated relative to the available node field
size; see the thread starting at:

http://www-mash.cs.berkeley.edu/dist/archive/ns-users/9807/0190.html

where I finally noticed the address space problem for the first time.
With ns 2.1b3 and later, a check cuts in and I get errors of the form:

Number of nodes exceeds node-field-size of 7 bits
    while executing
"error "Number of nodes exceeds node-field-size of $nodebits_ bits""
    (procedure "_o4" line 4)
    (Simulator check-node-num line 4)
    invoked from within
"$self check-node-num"
    (procedure "_o4" line 8)
    (Simulator node line 8)
    invoked from within
"$ns node"
    (file "torus25.tcl" line 379)

I'm not sure exactly when in the snapshot history that change was
implemented. Anyone?

hth,

L.

<http://www.ee.surrey.ac.uk/Personal/L.Wood/>PGP<L.Wood@surrey.ac.uk>