Rockwell Automation 1783-BMxxx Stratix 5700 Ethernet Managed Switches User Manual - Manual (Page 107)

Rockwell Automation Publication 1783-UM004E-EN-P - June 2014 107
Switch Software Features Chapter 3
Resilient Ethernet Protocol The Resilient Ethernet Protocol (REP) provides an alternative to Spanning Tree
Protocol (STP) to control network rings and loops, handle link failures, and
improve convergence time. REP controls a group of ports connected in a
segment, makes sure that the segment does not create any bridging loops, and
responds to link failures within the segment. REP provides a basis for
constructing more complex networks and supports VLAN load balancing.
REP is a segment protocol. One REP segment is a chain of ports connected to
each other and configured with a segment ID. Each segment consists of standard
(transit) segment ports and two user-configured edge ports. A switch can have no
more than two ports that belong to the same segment, and each segment port can
have only one external neighbor. A segment can go through a shared medium;
however, on any link, only two ports can belong to the same segment. REP is
supported only on Layer 2 trunk interfaces. Selecting the Switch for Automation
Smartport enables Layer 2 trunking. REP is supported on EtherChannels, but
not on an individual port that belongs to an EtherChannel.
You can construct almost any type of network based on REP segments. REP also
supports VLAN load-balancing, controlled by the primary edge port but
occurring at any port in the segment.
These types of REP ports are selectable in the Device Manager Web interface:
• Primary—This port is a primary edge port. This port always participates in
VLAN load balancing in the REP segment.
• Edge—This port is a secondary edge port. It also participates in VLAN
load balancing in the REP segment.
Edge ports are termination points of a REP segment. The user must
configure two edge ports, including one primary edge port, for each REP
segment. Entering edge without primary configures the port as a secondary
edge port. Primary and secondary edge ports must be configured even if
support of VLAN balancing is not required.
• Transit—This port is a non-edge port in the REP segment.
• No-Neighbor Primary—This port is a primary edge port connected a non-
REP switch.
• No-Neighbor—This port is a secondary edge port connected to a non-
REP switch.
The no-neighbor edge ports contain all properties of regular edge ports.
These ports enable the construction of a REP ring containing a switch that
does not support REP protocol.
• None—This port is not part of the REP segment.