If the service is using unicast only an I-VPLS still uses MFIB space and SPBM advertises the ISID. By using the default multicast tree locally, a node saves MFIB space. By using the no advertise-local SPBM does not advertise the ISIDs covered by the policy. Note the actual PBB multicast frames are the same regardless of policy. Unicast traffic is the not changed for the ISID policies.
The Static B-MAC configuration is allowed under Multi-Chassis LAG (MC-LAG) based SAPs and active/standby PW SDPs.
Unicast traffic follows the unicast path shortest path or single tree. By using the ISID policy Multicast/and unknown Unicast traffic (BUM) follows the default B-VPLS tree in the SPBM domain. This should be used sparingly for any high volume of multicast services.