3.6.1. Control Order Set

The control ordered set (CtlOS) is a message mechanism utilized by the UE link layer features credit-based flow control (CBFC) and link layer retry (LLR).

Control ordered sets use a control character of 0x5C on the xMII bus between the MAC/RS and PCS. This distinguishes them from the standard sequence ordered sets, which use a control character of 0x9C.

Order Set

Lane 0 (D0, control character)

Lane 1 (D1)

Lane 2 (D2)

Lane 3 (D3)

Lane 4 (D4)

Lane 5 (D5)

Lane 6 (D6)

Lane 7 (D7)

CtlOS

0x5C

Type

D2

D3

{D4[7:4], 0x6}

D5

D6

D7

The CtlOS type field is used to encode the CtlOS message type. The table below shows all UE CtlOS message type values.

UE Feature

CtlOS

Msg type value (D1)

LLR

ACK

0x01

NACK

0x02

INIT

0x03

INIT_ECHO

0x04

CBFC

CF Update

0x10

The commands in this section are defined for the general CtlOS message types, not specific to a particular UE feature. For example, the command documented in this section for configuring the spacing of CtlOS applies to all CtlOS message types, not just those for LLR or CBFC.