import re


def node_id_from_name(node_name):
    """Extracts integer node ID from a string formatted as V(RX{0}+, RX{0}-)."""
    regex = re.compile('(\d+)')
    match = regex.search(node_name)
    if match:
        return int(match.group(1))
    else:
        raise ValueError('Node name %s does not match regex' % node_name)