Model 914-X Series Modular Multiplexer System User Manual
Focal Technologies Corporation
Page 6-10
A Moog Inc. Company
Document Number: 914-0601-00
Rev.
5.0
6.2.1 914-EX Ethernet Ports
The 914-EX provides two un-switched, low latency 10/100/1000 BASE-T(X) Ethernet links through the 914-HDE
optical port. Both ports are default configured for 10/100/1000 BASE-T(X) auto-negotiation. Auto-negotiate settings
can be accessed via the Model 914 Diagnostic GUI when connected to the console 914-HDE diagnostic port. A
standard 8P8C (RJ45) modular jack provides the mechanical interface for the Ethernet port. The port is auto
MDI/MDIX capable, and supports jumbo frames up to 9000 bytes.
An optional “Link Fault Pass Through” can be enabled on a per port basis. This feature will disconnect the Ethernet
link if the far side is not linked. Therefore the system must be linked on both sides for the Ethernet link to be
established. Enabling or disabling this feature is done through the diagnostic GUI.
The 914-EX combines the traffic of both Ethernet ports along with diagnostic information onto a single medium
speed expansion channel to the 914-HDE. This bandwidth is dynamically shared between the 2 Ethernet ports
allowing for throughput up to 950 Mb/s.
Optionally the 914-EX can be specified to use 2 medium speed expansion channels. This doubles the bandwidth
of the Ethernet ports and is ideal for high bandwidth video over IP or GigE vision applications. Since the 914-HDE
motherboard multiplexes the Ethernet data from the 914-EX card and other expansion cards in the system the total
system bandwidth (BW) usage must be considered and be at or under the maximum optical bandwidth available.
Refer to section 3.2 for detailed information 914-X series card BW usage.
End-to-end latency through the multiplexer is a calculation adding a fixed electronic latency to the Ethernet frame
time which is a function of the frame length, and the optical latency which is a function of distance. Adding all three
together gives a total latency figure.
Table 6-7: Ethernet Latency
Latency Component / Link Speed
10 Mb/s
100 Mb/s
1000 Mb/s
FEL (Fixed Electronic Latency)
40
s
12
s
15
s
FT (Frame Time)
# Bytes * 0.8
s
# Bytes * 0.08
s
# Bytes * 0.008
s
OL (Optical Latency)
5
s / km
5
s / km
5
s / km
Latency = FEL + FT + OL