Cisco Catalyst 4500 Series Command Reference Manual page 652

rep block 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
SegmentFigure
Figure 2-2
Uplink
switch B
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.
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 block port 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 VLAN 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 block port 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.
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
2-594
2-2.
Neighbor Offset Numbers in a REP Segment
Forwarding
(1-50)
gi2/0/6
Switch A
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
Neighbor Offset Numbers in a REP
Uplink
switch C
Forwarding
(51-100)
gi2/0/8
OL-27596 -01