Configuring The Rep Administrative Vlan - Cisco Catalyst 4500 Series Configuration Manual

Configuring REP
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Configuring the REP Administrative VLAN

To avoid the delay introduced by relaying messages in software for link-failure or VLAN-blocking
notification during load balancing, REP floods packets at the hardware flood layer (HFL) to a regular
multicast address. These messages are flooded to the whole network, not just the REP segment. You can
control flooding of these messages by configuring an administrative VLAN for the whole domain.
Follow these guidelines when configuring the REP administrative VLAN:
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Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
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You cannot run REP and STP on the same segment or interface.
If you connect an STP network to the REP segment, be sure that the connection is at the segment
edge. An STP connection that is not at the edge could cause a bridging loop because STP does not
run on REP segments. All STP BPDUs are dropped at REP interfaces.
You must configure all trunk and PVLAN promiscuous trunk ports in the segment with the same set
of allowed VLANs, or a misconfiguration occurs.
REP ports follow these rules:
– If REP is enabled on two ports on a switch, both ports must be either regular segment ports or
edge ports.
– If only one port on a switch is configured in a segment, the port should be an edge port.
– If two ports on a switch belong to the same segment, both ports must be edge ports or both ports
must be regular segment ports.
– If two ports on a switch belong to the same segment, they must be both edge ports, both regular
segment ports, or one regular port and one edge no-neighbor port. An edge port and regular
segment port on a switch cannot belong to the same segment.
If two ports on a switch belong to the same segment and one is configured as an edge port and
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one as a regular segment port (a misconfiguration), the edge port is treated as a regular segment
port.
REP interfaces come up in a blocked state and remains in a blocked state until notified that it is safe
to unblock. You need to be aware of this to avoid sudden connection losses.
REP sends all LSL PDUs in untagged frames on the native VLAN. The BPA message sent to the
Cisco multicast address is sent on the administration VLAN, which is VLAN 1 by default.
REP ports can not be configured as one of these port types:
– SPAN destination port
– Private VLAN port
Tunnel port
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Access port
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REP is supported on EtherChannels, but not on an individual port that belongs to an EtherChannel.
There is a maximum of 384 REP segments per switch.
If you do not configure an administrative VLAN, the default is VLAN 1.
There can be only one administrative VLAN on a switch and on a segment (not enforced by
software).
The administrative VLAN cannot be the RSPAN VLAN.
Chapter 22 Configuring Resilient Ethernet Protocol
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