White Paper

© 2013 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 20 of 25
C2960-48(config-if-range)# switchport mode trunk
C2960-48(config-if-range)# exit
C2960-48(config)# !!!!!
C2960-48(config)# !! now configure the access ports.
C2960-48(config)# !! quick example of configuring interfaces
C2960-48(config)# !!
C2960-48(config)# interface range Gi4/0/1 – 48
C2960-48(config-if-range)# switchport mode access
C2960-48(config-if-range)# switchport access vlan 20
C2960-48(config-if-range)# spanning-tree portfast
C2960-48(config-if-range)# exit
C2960-48(config)#exit
C2960-48#
Recommended Deployment Strategies for Building FlexStack
These are the important items to consider when deploying FlexStack:
●
Configure the stack so that the uplinks are present on at least two stack members.
●
Use cross-stack EtherChannel to load balance the traffic on the uplinks.
●
If there are only two physical links, and EtherChannel is not desired, then use the feature called backup
interface.
●
When using 10 Gigabit Ethernet as the uplinks, separate the 10 Gigabit Ethernet uplinks across stack
members if possible.
◦ It is always recommended to have at least two uplinks from the stack to the aggregation device.
◦ This is standard best practice for any deployment regardless if stacking is present or not. It is
recommended for physical link redundancy.
●
It is recommended that the stack master not contain uplinks if it is possible to distribute the uplinks across
other stack members.
◦ This recommendation should only be followed in stacks with three or more members.
◦ If the master fails and it has the uplinks, then those uplinks are lost as well. If the master fails, and it does
not have any uplinks, this will cause a minimal amount of traffic loss.
◦ Configure one member to be the backup master. Use the Cisco IOS Software CLI configuration
command “switch <member number> priority <1-15>” to configure a backup. In case of master failure,
having a deterministic backup is useful.
●
When using only two uplinks in a stack of four members, put the uplinks on members that are not directly
connected with FlexStack links. Directly connected members are those connected together with FlexStack
connections. This is only relevant on FlexStack groups that contain four members.
◦ This recommendation is purely for stack bandwidth efficiency. Placing the FlexStack uplinks on directly
connected members is less efficient on stack bandwidth. In a four-member stack, with members
connected 1-2, 2-3, 3-4, 4-1, put the uplinks on members 2 and 4 or 1 and 3. (See Figure 10.)