xs Subnet Matrix SD Source Mask

The subnetwork source mask for this xsSubnetMatrixSDEntry. This is represented as an octet string with specific semantics and length as identified by the protocolDirLocalIndex component of the index. For example, if the protocolDirLocalIndex indicates an encapsulation of ip, this object is encoded as a length octet of 4, followed by the 4 octets of the ip address, in network byte order.