The Security Group service provides a common interface to interact with an account’s security groups, their rules, and virtual guest instances associated with the groups. A security group contains a set of IP filter rules that define how to handle incoming (ingress) and outgoing (egress) traffic to both the public and private interfaces of a virtual server instance. The rules that you add to a security group are known as [[SoftLayer_Network_SecurityGroup_Rule (type)|security group rules]]. Security groups can be assigned to one or more virtual servers by attaching virtual guest network components through [[SoftLayer_Virtual_Network_SecurityGroup_NetworkComponentBinding (type)|bindings]].
Additional information can be found in IBM Cloud Docs and SoftLayer API Examples https://console.bluemix.net/docs/infrastructure/security-groups/sg_index.html https://softlayer.github.io/classes/softlayer_network_securitygroup/