260-668066-001 Rev 024 February 2009 Vol. II-2-19
Eclipse User Manual
Port Up
Indicates that a valid Ethernet connection with valid Ethernet framing has been
detected.
Resolved
Indicates a port connection has been resolved for an auto speed-duplex setting.
Priority Mapping
A priority mapping screen supports selection of queue-controller operation for mode
and mapping. A mode selection applies to all ports.
To prioritize ingressing traffic over a DAC ES link a 4-level prioritization of high,
medium high, medium low, and low is used with a weighting of 8:4:2:1. For example, 8
high priority packets are sent for every 1 low priority packet. Mapping is used to convert
the 4 DAC ES levels to the 8 priority levels of 802.1p, and 64 levels of DiffServ. Mapping
is user configurable.
• Port Default enables the Port Priority option. It ignores any 802.1p VLAN CoS
priority tags or IP DiffServ priority values. It only has relevance where two or more
ports share a common channel.
• 802.1p provides prioritization based on the three-bit CoS field within a VLAN tag.
Each of the possible eight tag priority values are mapped into a four-level (2-bit) IDU
ES priority level.
• DiffServ provides prioritization based on the six bits of the IP packet DiffServ or Type
of Service byte. Each of the possible 64 levels are mapped into a four-level (2-bit)
priority level.
• 802.1p-then-DiffServ provides prioritization based first on the 802.1p VLAN tag,
and then on the DiffServ or Type of Service byte.
• DiffServ-then-802.1p provides prioritization based first on the IP packet DiffServ or
Type of Service byte, then on the 802.1p VLAN tag.
Flow Control
Flow Control is an option for full-duplex links only. It is implemented through use of
IEEE 802.3x PAUSE frames, which tell the remote node to stop or restart transmission
to ensure that the amount of data in the receive buffer does not exceed a ‘high water
mark’. The receiver will signal to the transmitter to stop transmitting until sufficient
data has been read from the buffer, triggered by a ‘low water mark’, at which point the
receiver signals to the transmitter to resume transmission. To be effective, flow control
must be established from the originating source through to the end point, and vice
versa, which means the equipment connected to the IDU ES ports and beyond should
also be enabled for flow control.
Disable Address Learning
MAC Address Learning is default implemented to support efficient management of
Ethernet traffic in multi-host situations. The option to disable Address Learning is
primarily for use in an Ethernet ring network where protection is provided by an
external RSTP switch. To avoid conflict between the self-learning function within IDU
ES and the external RSTP switch during path failure situations, the IDU ES capability
must be switched off.
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