cx82100 Conexant Systems, Inc., cx82100 Datasheet - Page 120

• Manufacturer Part Number: cx82100
• Description: Home Network Processor Hnp
• Manufacturer: Conexant Systems, Inc.

7-22
Conexant Proprietary and Confidential Information
Address Filtering Modes
Eight different address filtering modes are supported in the HNP. These modes are
configured through the E_NA_PM, E_NA_PR, E_NA_IF, E_NA_HO, and E_NA_HP
bits of the Network Access Register (see Section 7.11.3). Table 7-7 lists the combination
of these bits to select the desired address filtering mode. Each mode is described below.
Table 7-7. Address Filtering Mode
16 Perfect Filtering Mode. RMAC provides support for the perfect filtering of up to 16
Ethernet unicast or multicast addresses. Any mix of addresses can be used. The 16
addresses used will occupy all of the allocated space in the setup-frame.
Inverse Filtering Mode. In this mode, all frames with addresses that match any of the 16
perfect addresses in the setup frame will be rejected. Frames with addresses that do not
match any of the 16 perfect addresses in the setup frame will be accepted.
One Perfect Filtering + 512-Hash Bit Imperfect Filtering Mode. RMAC supports one,
single unicast address to be perfectly filtered with an unlimited number of multicast
addresses to be imperfectly filtered. The single address that is to be perfectly filtered will
need to reside in byte locations <156, 157>, <160, 161>, <164, 165> of the setup frame.
The lower 16 bits of the first 32 entries of the setup frame is treated as a 512-bit hash
table for imperfect filtering.
This mode supports the needs of applications that require one, single physical address to
be filtered as the node's address, while allowing reception of more than 16 multicast
addresses without suffering the overhead of passing all multicast frames to the host.
512-Hash Bit Imperfect Filtering Only Mode. RMAC supports imperfect filtering for
an unlimited number of unicast addresses as well as multicast addresses. The lower 16
bits of the first 32 entries of the setup frame represents a 512-bit hash table. All addresses
are used to generate indices into the hash table. Frames with addresses causing a hash
table hit are passed.
This mode supports the needs of applications that require more than one physical address
to be filtered as the node's address, while allowing reception of more than 16 multicast
addresses without suffering the overhead of passing all multicast frames to the host.
16 Perfect Filtering
Inverse Filtering
1 Perfect Filtering +
512-Hash Bit Imperfect
Filtering
512-Hash Bit Imperfect
Filtering Only
Promiscuous
Pass All Multicast
Pass All Multicast + 16
Perfect Filtering
Pass All Multicast + 1
Perfect Filtering
Address Filtering Mode
CX82100 Home Network Processor Data Sheet
E_NA_PM:
Multicast)
(Pass All
0
0
0
0
0
1
1
1
x
E_NA_PR:
Any Good
(Receive
Frame)
0
0
0
0
1
1
0
0
0
E_NA_IF:
Filtering)
(Inverse
0
1
0
0
0
0
0
0
0
E_NA_HO:
(Hash
Only)
0
0
0
1
0
1
1
0
0
E_NA_HP:
Filtering)
Perfect
(Hash/
101306C
0
0
1
1
1
1
0
1
x