TXC-06880BIOG Transwitch Corporation, TXC-06880BIOG Datasheet - Page 69

• Manufacturer Part Number: TXC-06880BIOG
• Manufacturer: Transwitch Corporation

Specifications of TXC-06880BIOG

• Operating Supply Voltage (typ): 1.8/3.3V
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

PRELIMINARY TXC-06880-MB, Ed. 4
February 2005
OPERATIONAL
6.3 PORT AGGREGATION
6.4 ETHERNET HALF DUPLEX
AGGREGATE
6.3.1 Normal vs. Aggregate Mode
NORMAL
6.4.1 Overview
MODE
In Port Aggregation mode, the Envoy-CE2 aggregates all the Ethernet ports’ receive data
onto a single SPI-3 port. Port Aggregation mode may be programmed in SPI-3 Multi-PHY
mode or SPI-3 Single-PHY mode. In Multi-PHY mode, all the Ethernet ports aggregate traffic
onto SPI-3 port 0. A round robin mechanism schedules traffic from multiple Ingress FIFOs
(per Port Ingress FIFOs) onto a single SPI-3 Port. Port Aggregation in Single-PHY mode is
similar to the above except that there is no concept of a SPI-3 port and hence no SPI-3 port
address. The Envoy-CE2 emulates a single PHY/Link layer device in Single-PHY operation.
A programmable port number is appended to the packet or chunk (depending on whether the
device is in burst mode or not). The programmable port number may be used by the
downstream device to identify the source of the packet from the Envoy-CE2 Ethernet
interface.
In the SPI-3 receive to Ethernet Transmit direction, a prepended port number is required to
de-multiplex the incoming packet stream on SPI-3 port 0 onto multiple Ethernet ports. The
port number is assigned from 0 to 15 and a byte of packet data is used to convey this
information. The appended port number will be removed before transmission onto the
appropriate Ethernet interface.
* Note: The single port is either in Multi-PHY or Single-PHY mode.
In Half-Duplex mode, two or more Ethernet devices are connected to a common transmission
medium and when one Ethernet device transmits, the others listen. In the case where two
Ethernet devices transmit at once, a “Collision” is said to have occurred. A “Jam Sequence” is
transmitted by the transmitting Ethernet device indicating the occurrence of a collision. The
contention is resolved by each of the Ethernet devices responsible for the collision, backing
off, and attempting to re-transmit after a time period. This method is called Carrier Sense
Multiple Access/Collision Detection (CSMA/CD). The Envoy-CE2 Configurable Media Access
Controller implements the IEEE 802.3 compliant CSMA/CD algorithm. For a complete
definition of this algorithm, please refer to the IEEE 802.3 specification.
Note: Carrier Sense and Collision detection status is indicated by the Ethernet PHY device to
Following is an outline based on the Envoy-CE2 Configurable MAC.
the Envoy-CE2 via the SMII and MII interface only. Please refer to the Serial Media
Independent Interface (SMII) specification for further details.
Default
Yes
No
Backpressure
Port SPI-3 Tx
Per Ethernet
Yes
No
- Operation -
Tagging
Packet/
Chunk
Yes
No
PAUSE Frame
Ethernet Port
support per
Yes
Yes
Chunking
SPI-3
Envoy-CE2 Device
Yes
Yes
DATA SHEET
SPI-3 Ports
Number of
supported
Multiple
Single*
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