B&B Electronics 856-14205--29 - Manual - Manual (Page 32)

Configuration
27
Explanations:
Preamble
DA
CRC
IFG
= 8 bytes
= EtherNet Destination Address
= EtherNet Checksum
= 12 bytes
Unit Rate Control
Enable/Disable Allows the end user to globally configure all
Bandwidth settings when enabling Unit Rate Control
(Flow Control). If the END device connected to the
port also has Flow Control enabled, this will ensure
packets will not be dropped.
OSI Notes: The Bandwidth Limit functions can be
adjusted to only count the Layer 1, 2, or 3 portions of the
physical line rate. Layer 1 is used to relate Bandwidth to
the physical line rate where a 100BaseT Ethernet line can
carry a MAX bandwidth of 100Mbps. Layer 2 may be more
useful when the Ethernet Frame may be carried over
several different physical protocols such as SONET or SDH.
Only the bandwidth required by the Ethernet frame is
counted, making this a more consistent number over
different protocols. Layer 3 counting could be used when
a relationship to the actual customer data or line payload
is required. If a 10 Mbps customer file needs to be sent in
one second, then a minimum bandwidth limit of 10Mbps
would need to use Layer 3 counting to allow this.
It must be noted that only Layer 1 counting is not affected
by the size of the Ethernet frame. At 64 byte Ethernet
frames, the MAX bandwidth the line can support at Layer 2
is only 76.2% of the line rate. This maximum falls to
54.8% of the line rate when counting is further limited by
only counting Layer 3 payload data.
VERSION
Entering version will display the version of the firmware operating the iMcV-
Giga-FiberLinX-III.