Broadcast Information within a network

Hello community, I have a complex network (graph), I want to randomly pick one node and let the node broadcast information through the network based on the average distance of the network. Can some please help....I've no idea how to implement this. Graph data set (Power Grid) can be downloaded from http://www-personal.umich.edu/~mejn/netdata/. Below is my code for reading and ploting the graph.

%Extracting edges from gml file graph
fileName = 'power.gml';
inputfile = fopen(fileName);
Edges=[];
l=0;
k=1;
while 1
      % Get a line from the input file
      tline = fgetl(inputfile);
      % Quit if end of file
      if ~ischar(tline)
          break
      end
      nums = regexp(tline,'\d+','match');
      if length(nums)
          if l==1
              l=3;
              Edges(k,2)=str2num(nums{1});  
              k=k+1;
              continue;
          end
          Edges(k,1)=str2num(nums{1});
          l=1;
      else
          l=0;
          continue;
      end 
end
Edges = Edges+1;
NewEdge = Edges;
%Edges(:,1:2) = sort(Edges(:,1:2)); 
Edges = unique(Edges(:,1:2),'rows','stable');
G = graph(Edges(:,1), Edges(:,2));      % create a graph from A
deg = degree(G);
figure                                  % visualize the graph
plot(G);
title('Power Grid, Before Movement')
NewEdge = NewEdge(randperm(size(NewEdge,1)),:);  % <-- Optional --
nodesize = numnodes(G);
size = nodesize;
not = [];
x = [];
for c = 1:size
[P,d] = shortestpath(G,c,nodesize);
if d == Inf
    not = [not, d];
else
x = [x, d];
end
end
LongestShortestPath = max(x)
disp('Before Change');
AverageDistance = mean(x)
AverageDegree = mean(deg)

[Walter Roberson]

What does it mean to "broadcast information" in your network?

[Isaac Osei Agyemang]

lets say sending a random letter generated between a to z. So assuming that node 1 has a degree of 3; thus it has 3 nodes connected to it, it should send the random letter generated to these 3 nodes.