This table contains the mapping of IP Precedence to DSCP.
This mapping table consist of eight IpPrecedence values
(0 through 7) and their corresponding DSCP values. The
mapping given by this table is used for all packets received
on an interface if and only if that interface has a trust state,
as given by the value of csqIfTrustState for the interface,
of 'trustIpPrec'.