Multimode Fiber Optic Network
ESX-1320/ESX-1380 Installation Guide B-3
B.3 MULTIMODE FIBER OPTIC NETWORK
When connecting a multimode fiber optic link segment to the ESX-1380,
ensure the network meets the following requirements:
• Cable Type: Use the following multimode fiber optic media:
- 50/125 µm fiber optic cabling
- 62.5/125 µm fiber optic cabling
- 100/140 µm fiber optic cabling
• Attenuation: You must test the fiber optic cable with a fiber optic
attenuation test set adjusted for an 850 nm wavelength. This test
verifies that the signal loss in a cable falls within the following
acceptable levels:
- 13.0 dB or less for a 50/125 µm fiber cable segment
- 16.0 dB or less for a 62.5/125 µm fiber cable segment
- 19.0 dB or less for a 100/140 µm fiber cable segment
• Budget and Propagation Delay: When you determine the maximum
fiber optic cable length to incorporate fiber runs into your network, you
must calculate and consider the fiber optic budget (a total loss of
10.0 dB or less is permissible between stations) and total network
propagation delay.
To determine the fiber optic budget, combine the optical loss due to
the fiber optic cable, in-line splices, and fiber optic connectors.
Typical loss for a splice and connector (together) equals 1 dB or less.
Network propagation delay is the amount of time it takes a packet to
travel from the sending device to the receiving device. Total
propagation delay allowed for the entire network must not exceed
25.6 µs in one direction (51.2 µs round trip). If the total propagation
delay between any two nodes on the network exceeds 25.6 µs, you
must use bridges or switches.
• Length: The maximum possible multimode fiber optic cable length is
2 km (1.24 miles). However, IEEE 802.3 FOIRL specifications specify
a maximum of 1 km (0.62 miles).
