Security Groups : For "Other Protocol" rule, NeutronSecurityRule.getSecurityRuleProtocol() is set to NULL

From openstack Horizon I have created a security group rule for "Other Protocol" (ID : 0 to 255) and when I check the datastore the protocol filed was not set. I am work on net-virt:security groups implementation and on port added/update NorthBound event I am reading the MD for security groups rule associated to the neuton port. When the port is assocaited to "Other Protocol" rule the protocol field is set to NULL (protocol field is properly set for ICMP/UDP/TCP). I verified using the following neutron APIs:

http://172.16.100.47:8181/restconf/config/neutron:neutron/security-groups/

{ "uuid": "565faa54-2e2c-4481-bb77-b5dc64e56024", "security-rules": [ "159eb2e0-d16e-4162-b44b-7232d826adbf", "21a367c0-df97-4f2e-9e7e-fcc5f8ef5180", "04d74957-dd00-48fb-993b-61e86308f13d", "9d2e779a-6b0c-4921-8822-086164b1d2a8" ], "tenant-id": "5730197f-a527-4c6e-b56d-579ae544ef5a", "name": "OTHERS", "description": "OTHER-PROTO" }

,

http://172.16.100.47:8181/restconf/config/neutron:neutron/security-rules/security-rule/9d2e779a-6b0c-4921-8822-086164b1d2a8/

{
"security-rule": [

{ "id": "9d2e779a-6b0c-4921-8822-086164b1d2a8", "security-group-id": "565faa54-2e2c-4481-bb77-b5dc64e56024", "tenant-id": "5730197f-a527-4c6e-b56d-579ae544ef5a", "ethertype": "neutron-constants:ethertype-v4", "direction": "neutron-constants:direction-egress" }

]
}

ICMP:

http://172.16.100.47:8181/restconf/config/neutron:neutron/security-rules/security-rule/adc94c53-21a3-440b-a24c-20efd357520f/

{
"security-rule": [

{ "id": "adc94c53-21a3-440b-a24c-20efd357520f", "security-group-id": "42a139a8-0412-4b67-b7a4-8f1949532f43", "remote-ip-prefix": "0.0.0.0/24", "tenant-id": "5730197f-a527-4c6e-b56d-579ae544ef5a", "ethertype": "neutron-constants:ethertype-v4", "direction": "neutron-constants:direction-ingress", "protocol": "neutron-constants:protocol-icmp" }

]
}