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IXF1104 4-Port Gigabit Ethernet Media Access Controller
Datasheet 173
Document Number: 278757
Revision Number: 007
Revision Date: March 25, 2004
8.4.2 MAC RX Statistics Register Overview
The MAC RX Statistics registers contain the MAC receiver statistic counters and are cleared when
read. The software polls these registers and accumulates values to ensure that the counters do not
wrap. The 32-bit counters wrap after approximately 30 seconds.
Table 93 covers the RX statistics for the four MAC ports. Port_Index is the port number (0, 1, 2, or
3).
Table 93. MAC RX Statistics ($ Port_Index + 0x20 – + 0x39) (Sheet 1 of 4)
Name Description Address Type
1
Default
RxOctetsTotalOK
Counts the bytes received in all legal frames,
including all bytes from the destination MAC
address to and including the cyclic redundancy
check (CRC). The initial preamble and Start of
Frame Delimiter (SFD) bytes are not counted.
Port_Index
+ 0x20
R 0x00000000
RxOctetsBAD
2
Counts the bytes received in all bad frames with
legal size (frames with CRC error, alignment
errors, or code violations), including all bytes
from the destination MAC address to (and
including) the CRC. The initial preamble and
SFD bytes are not counted. Frames with illegal
size do not add to this counter (shorts, runts,
longs, jabbers, and very longs).
Note: This register does not count octets on
undersized received packets.
Port_Index
+ 0x21
R 0x00000000
RxUCPkts
The total number of unicast packets received
(excluding bad packets).
Note: This count includes non-pause control and
VLAN packets, which are also counted in other
counters. These packet types are counted twice.
Take care when summing register counts for
reporting Management Information Base (MIB)
information.
Port_Index
+ 0x22
R 0x00000000
RxMCPkts
The total number of multicast packets received
(excluding bad packets)
Note: This count includes pause control packets,
which are also counted in the PauseMacControl-
ReceivedCounter. These packet types are
counted twice. Take care when summing register
counts for reporting MIB information.
Port_Index
+ 0x23
R 0x00000000
RxBCPkts
The total number of Broadcast packets received
(excluding bad packets).
Port_Index
+ 0x24
R 0x00000000
RxPkts64Octets
The total number of packets received (including
bad packets) that were 64 octets in length.
Incremented for tagged packets with a length of
64 bytes, including tag field.
Port_Index
+ 0x25
R 0x00000000
1. RO = Read Only, No clear on Read; R = Read, Clear on Read; W = Write only; R/W = Read/Write, No clear;
R/W/C = Read/Write, Clear on Write
2. When sending in large frames, the counters can only handle certain limits. The behavior of the LongErrors
and VeryLongErrors counters is as follows: VeryLongErrors counts frames that are 2*maxframesize,
dependent upon where maxframesize is set. If maxframesize sets greater than half of the available count in
RxOctetsBad (2^14-1), VeryLongErrors is never incremented, but LongErrors is incremented. This is due to
a limitation in the counter size, which means that an accurate count will not occur in the RxOctetsBAD
counter if the frame is larger than 2^14-1.
3. This register is relevant only when configured for copper operation.
4. This register is relevant only when configured for fiber operation (line side interface is SerDes).