public String getProtocol() {
        return this.protocol;
    }
<p>
The IP protocol name (<code>tcp</code>, <code>udp</code>, <code>icmp</code>, <code>icmpv6</code>) or number.
</p>

@return The IP protocol name (<code>tcp</code>, <code>udp</code>, <code>icmp</code>, <code>icmpv6</code>) or
        number.
aws-java-sdk-fms/src/main/java/com/amazonaws/services/fms/model/SecurityGroupRuleDescription.java