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hierarchical, multicast routing etc



Padma's hierarchical routing fix works well for me; I'm able to create
large topologies and run multicast simulations over them without
the problems of Node expandaddr/multicast interaction.

I have a question about using CtrMcast on a topology that includes 
simplex links, though.

CtrMcast assumes fully duplex links throughout, and doesn't appear
able either to cope with either asymmetric simplex routing or fail
elegantly. (Mind you, that's probably covered by the 'Currently, only
DV routing can generate multipath routes' in section 15.2.) 

I've experimented with encouraging various asymmetric routings via
link weighting, but that appears to have no effect on the CtrMcast
routing. And since 

$mrthandle set-c-rp { <rendezvous point nodes> } 

errors for me:

hierarchical routing:
_o6414: unable to dispatch method set-c-rp

etc, meaning I can't set explicit rendezvous points, I appear to have
no control over how CtrMcast spans the group - although it does span
the group.

Cheers,

L.

As for simplex errors with CtrMcast:

ns: _o3116 join-group _o5342 0x8000: can't read "link_(6:5)": no such
element in array
    while executing
"return $link_($from:$to)"
    (procedure "_o4" line 6)
    (Simulator RPF-link line 6)
    invoked from within
"$ns RPF-link $target [$upstreamtmp id] $tmp"
    (procedure "_o4827" line 33)
    (CtrMcastComp compute-branch line 33)
    invoked from within
"$Agent compute-branch $s $group [$Node id]"
    (procedure "_o4970" line 27)
    (CtrMcast join-group line 27)
    invoked from within
"$proto join-group $group"
    (procedure "_o3120" line 4)
    (McastProtoArbiter join-group line 4)
    invoked from within
"$mcastproto_ join-group $group"
    (procedure "_o3116" line 5)
    (Node join-group line 5)
    invoked from within
"_o3116 join-group _o5342 0x8000"


<http://www.ee.surrey.ac.uk/Personal/L.Wood/>PGP<[email protected]>