[802.3ae] XSBI Bit ordering
hi all,
While going through the IEEE 802.3 ae Draft 3.1
Clause 51 describes XSBI mapping as following
For the XSBI instantiation of the PMA service interface, the mapping of
bits between the PMA service interface and the XSBI physical interface
is defined for transmit in Table 51 2 and for receive in Table 51 3.
Table 51 2 Transmit bit mapping
Name Bit numbers
PMA service tx_data-group 0 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15
interface
^ ^
|
|
XSBI physical xsbi_tx 15 14 13 12 11 10 9 8 7
6 5 4 3 2 1 0
interface
Table 51 3 Receive bit mapping
Name
Bit numbers
PMA service rx_data-group 0 1 2 3 4
5 6 7 8 9 10 11 12 13 14 15
interface
^
^
|
|
XSBI physical xsbi_rx 15 14 13 12 11
10 9 8 7 6 5 4 3 2 1 0
interface
Clause 51 does not say bit mapping will be done
only for LAN or WAN or for both.
But in Clause 49
The ordering of bits and octets for the case when no WIS is present
between the PCS and PMA is shown in Figure 49 2
with no bit reordering meaning that PMA LSB is mapped to LSB of PCS.
But when WIS is present bit order change is shown in Figure 49-3.
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Question
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Do we need to change the bit ordering for both LAN and WAN application?
If it is only for WAN i.e., with WIS only then Clause 51 has to be
updated with this point in the XSBI description.
Please correct if i am wrong or miss understood.
Thanks
satya
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