Siemens X-400 Glossary, Ring port, Segment, Signaling Contact, Single mode, Snmp, Spanning Tree

Glossary

Redundancy manager Switch in a ring topology that does not forward any frames between its

(RM)ring ports if there are functioning connections between all other switches. As soon as a connection between two switches is inter- rupted, the redundancy manager forwards frames between its ring ports and so restores an intact connection between all switches.

Ring port	Two ports in a switch via which it is connected with other switches to
	form a ring. One switch must be configured as the redundancy man-
	ager in the ring. This sends test frames via the ring ports that are for-
	warded by all the ring ports of the other switches in the ring. This
	makes sure that the ring does not have any interruptions.
Segment	In the Ethernet bus system, transceivers connected together over the
	bus cable along with the nodes connected over patch cables form a
	segment. Several such segments can be connected via repeaters.
	When using twisted pair and fiber-optic cables, each subsection forms
	a segment.
Signaling Contact	Floating relay contact via which the detected error states can be sig-
	naled.
Single mode	In single mode transmission, the pulse is transmitted by a straight
	mode (wave). Attenuation is mainly caused by physical absorption and
	dispersion as well as by mechanical bending. The amount of attenua-
	tion depends among other things on the wavelength of the input light.
	Single mode fiber-optic cables have an outer diameter of 125 µm and 9
	or 10 µm core diameter. The smaller core diameter degrades the pulse
	edges less than multimode transmission and allows greater transmis-
	sion distances.
SNMP	Simple Network Management Protocol. Standardized protocol for
	transporting network management information.
Spanning Tree	The Spanning Tree protocol (STP) allows redundant transmission
	paths. This prevents circulating frames and, if a fault develops, pro-
	vides an alternative path within 20 - 30 seconds (reconfiguration time).

142	Operating Instructions for SCALANCE X-400 Industrial Ethernet Switches
	C79000-G8976-C186-03