Specifications

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Catalyst 4500 Se ries S wit ch C is co IO S C om mand R efer ence —Re lease I OS XE 3 .3.0 XO(1 5.1 (1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
rep block port
Figure 2-2 Neighbor Offset Numbers in a REP Segment
Note You would never enter an offset value of 1 because that is the offset num ber 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, VL AN load balancing begins a fter the
configured preemption time period elapses without another link failure. The alternate port specified in
the load-balancing conf iguration blocks the configu red VLANs a nd unbloc ks all other s egment 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) associate d to a MAC address (unique in the
network). To determine the port ID of a port, enter the show interface interface-id rep d eta il p rivileged
EXEC command.
There is no limit to the number of times that you can enter the rep block port id port-id vlan vlan-list
interface configuration command. You can block an unlimited number, range, or sequence of VLANs.
When you use the rep bl ock po rt id port-id vlan vlan-list interface configuration command on a REP
primary edge port to block a VLAN list and then use the same command to block another VLA N list on
the same port, the second VLAN list does not replace the first VLAN list but is appended to the first
VLAN list.
When you use the rep bl ock po rt id port-id vlan vlan-list interface configuration command on a REP
primary edge port to block a VLAN list on one port and then use the same command to block another
VLAN list on another port, the original port number and VLAN list are overwritten.
Examples This example shows how to configure REP VLAN load bala ncing on the Switch B primary edge port
(Gigabit Ethe rnet p ort 1/0/1) and to configure Gigabit Ethernet port 1/1 of Switch A as the alternate port
to block VLANs 1 to 100. The alternate port i s identified by its port ID, show n in bold in the output of
the show interface rep detail command for the Switch A port.
Switch A# show interface gigabitethernet1/1 rep detail
GigabitEthernet1/1 REP enabled
Segment-id: 2 (Segment)
PortID: 0080001647FB1780
Preferred flag: No
Operational Link Status: TWO_WAY
Current Key: 007F001647FB17800EEE
Switch A
Uplink
switch B
gi2/0/6
Forwarding
(1-50)
gi2/0/8
Forwarding
(51-100)
Uplink
switch C
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