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Cisco ASR 901 Aggregation Services Router Command Reference Guide
OL-26031-07
Chapter 1 CLI Command Reference
rep block port
Usage Guidelines
You must enter this command on the REP primary edge port.
When you select an alternate port by entering an offset number, this number identifies the downstream
neighbor port of an edge port. The primary edge port has an offset number of 1; positive numbers above
1 identify downstream neighbors of the primary edge port. Negative numbers identify the secondary
edge port (offset number -1) and its downstream neighbors. See
Neighbor Offset Numbers in a REP
SegmentFigure 1-2
.
Figure 1-2
Neighbor Offset Numbers in a REP Segment
Note
You would never enter an offset value of 1 because that is the offset number of the primary edge port
itself.
If you have configured a preempt delay time by entering the
rep preempt delay
seconds
interface
configuration command and a link failure and recovery occurs, VLAN load balancing begins after the
configured preemption time period elapses without another link failure. The alternate port specified in
the load-balancing configuration blocks the configured VLANs and unblocks all other segment ports. If
the primary edge port cannot determine the alternate port for VLAN balancing, the default action is no
preemption.
Each port in a segment has a unique port ID. The port ID format is similar to the one used by the spanning
tree algorithm: a port number (unique on the bridge) associated to a MAC address (unique in the
network). To determine the port ID of a port, enter the
show interface
interface-id
rep detail
privileged
EXEC command.
Examples
This example shows how to configure REP VLAN load balancing on the Switch B primary edge port
(Gigabit Ethernet port 0/1) and to configure Gigabit Ethernet port 0/2 of Switch A as the alternate port
to block VLANs 1 to 100. The alternate port is identified by its port ID, shown in bold in the output of
the
show interface rep detail
command for the Switch A port.
Switch A#
show interface gigabitethernet0/2 rep detail
GigabitEthernet0/2 REP enabled
Segment-id: 2 (Segment)
PortID: 0080001647FB1780
Preferred flag: No
Operational Link Status: TWO_WAY
Current Key: 007F001647FB17800EEE
Port Role: Open
Blocked Vlan: <empty>
Admin-vlan: 1
E2
E1
-1
-2
-3
-4
-5
-6
-7
-8
-9
2
1
10
9
8
7
6
5
4
3
201890
E1 = Prim
a
ry edge port
E2 = Second
a
ry edge port
Off
s
et number
s
from the prim
a
ry edge port
Off
s
et number
s
from the
s
econd
a
ry edge
port (neg
a
tive number
s
)