TD021000-0IF
6
Operation
Switching
The EISC uses an 8K-address look-up table augmented with 64 entries of
Content Addressable Memory. A hashing algorithm is used to update the table.
Addresses are aged in about 300 seconds. Runt packets (less than 64 bytes) and
oversize packets (greater than 1536 bytes) are discarded.
Data Storage
Data storage buffer for Ethernet packets consists of 156 k bytes of SSRAM.
Data Forwarding
An entire Ethernet packet must be received before forwarding occurs.
Flow Control
Each port automatically negotiates flow control for either half- or full-duplex
operation, if auto-negotiation is enabled. In full-duplex mode, the PAUSE
function is supported. In half-duplex mode, the backpressure method is used.
When flow control is disabled, the destination port of an incoming packet is
checked and, if found to be congested, the packet is discarded to avoid blocking
the packet stream.
Broadcast Storm Control
Using a storm-control counter, each port will pass 64 continuous broadcast
packets before dropping extra ones. The counter will reset every 800 ms or after
receiving a packet whose Device ID is other than ff ff ff ff ff ff.
LED Indicators
P
(green)
Power
. Glows when power is supplied to the EISC.
(Numbered LEDs)
(green/yellow)
Link/Activity
. Each port has an LED that glows if a link
exists:
green
for 100 Mbps operation or
yellow
for 10
Mbps operation. It flashes as data transfer occurs.
S
(green)
Fault Relay Status
. This LED functions in accordance with
its configuration setting. See the User Manual for details.
Ports
All ports are wired MDIX — allowing DTE equipment to connect via straight-
through cables — except that Port 16X is wired MDI to permit the cascading of
switches without the need of a crossover cable. Note that Port 16 and Port 16X
cannot be used simultaneously
.
Advanced Operation
Advanced operation (requiring a null-modem cable) is explained in the User
Manual located on the provided CD-ROM.