QT2022/32 - Data Sheet: DS3051
12 Extended Link Monitoring Feature (QT2032 and QT2022)
12.1 Overview
The QT2022/32 includes an optional Extended Link Monitoring feature. This feature allows PHY level diagnostics
of the link using the inter-packet gap space between traffic data. The PHY devices at both ends of the link must
support this feature to take advantage of it. This feature has no effect on traffic, nor does it affect devices that do
not support the feature. It includes the following capabilities:
•
•
Remote PHY Error Monitoring
Remote PHY Register Read/Write Capability.
Extended Link Monitoring is performed between two devices connected on a fiber optic link by means of a query
message in each direction.
Figure 41: Schematic Representation of Extended Link Monitoring Transaction Between Two PHYs
Query from Device A
QT2032/
QT2022
Device A
QT2032/
QT2022
Device B
Query from Device B
By default, query generation and query response is disabled. A device will generate query messages on its Tx fiber
output when its query generation algorithm is enabled by setting MDIO Register bit 3.CC00h.0 to ‘1’. The remote
device will respond to query messages if its query response algorithm is enabled by setting MDIO register bit
3.CC00h.1 to ‘1’. If set properly, the devices will communicate and establish a successful link. Once a successful
link is established, the extended link monitoring features may be used.
Extended Link Monitoring will work in PCS and PMA loopback mode for debug purposes.
•
No /A/ codes are used as part of the Extended Link Monitoring procedure as these may cause deskew pro-
tocol violations on XAUI.
•
No incomplete ||R|| or ||K|| ordered sets appear on the XAUI bus as these have a likelihood of being cor-
rectly identified as idle columns.
Revision 5.11
AppliedMicro - Confidential & Proprietary
109
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
