Value,Meaning,Reference
0,There is only one Signature Group.,[RFC5848]
1,"Each PRI value is associated with its own      
Signature Group.",[RFC5848]
2,"Each Signature Group contains a range of PRI   
Values.",[RFC5848]
3,"Signature Groups are not assigned with any of  
the above relationships to PRI values of the
syslog messages they sign.",[RFC5848]
4-7,Unassigned,
8-9,Reserved for Private Use,[RFC5848]