Sets the length of a port bundle — how many ports are grouped together to identify one subscriber under the PortBundle-Host Key feature. This directly trades off address-sharing density against per-subscriber port availability: a shorter bundle length lets more subscribers share one public IP, at the risk of starving subscribers who open many simultaneous connections, while a longer one supports fewer subscribers per IP but each gets more headroom. A carrier-grade NAT deployment sharing one public IPv4 address across 640 subscribers via 65,536 usable ports might set cssgPortMapLength to 100, giving each subscriber a 100-port bundle with some ports held in reserve.