package SSH;
has username => (is => 'rw', isa => 'Str');
sub connect {
[...]
$self->send($self->username);
}

package Client;
extends qw(SSH);
has username => (... default => 'admin');

package Server;
extends qw(SSH);
has username => (... default => 'root');

package main;
my $client = Client->new();
my $server = Server->new();

$client->connect();
$server->connect();