Updating software versions with DT

For 15.14.x and later

Beginning with software release 15.14.x, when updating to a new software release on switches configured for DT (Distributed Trunking) on LACP type trunks, you must update the DT partner with the lowest Base MAC address first. When this partner returns to operation, then update the other partner. Use the show system command to determine the base MAC address on a given switch.

From no DT Keepalive support to shared DT Keepalive support

When updating software from a version that does not support DT Keepalive (prior to version K.15.03) to a version that supports shared DT keepalive (K.15.03 and greater), use the following procedure:

Procedure

Disable the ISC interface on both switches, and then upgrade the software. Assume a2 is configured as switch-interconnect.
```
switch# int a2 disable
switch# write mem
```
Configure one of the existing uplink VLANs as a keepalive VLAN, and then configure the destination keepalive IP address (peer’s keepalive IP address) on both switches at bootup.
```
switch# distributed-trunking
peer-keepalive vlan 2
switch# distributed-trunking
peer-keepalive destination 20.0.0.2
```
Ping the keepalive destination address to make sure that there is connectivity between the two DT switches (keepalive VLANs.)
Enable the ISC link on both switches and then execute write memory. Assume a2 is configured as switch-interconnect.
```
switch# int a2 enable
switch# write mem
```

From no DT Keepalive support to dedicated point-to-point DT Keepalive support

When updating software from a software version that does not support DT keepalive (prior to version K.15.03) to a version with dedicated point-to-point keepalive (K.15.03 and greater), use the following procedure:

Disable the ISC interface on both switches, and then upgrade the software. Assume a2 is configured as switch-interconnect.
```
switch# int a2 disable
switch# write mem
```
At switch bootup, create a dedicated VLAN for keepalive, and assign only the keepalive link port as a member port of the VLAN. Configure the keepalive destination IP address.
```
switch# distributed-trunking
peer-keepalive vlan 2
switch# distributed-trunking
peer-keepalive destination 20.0.0.2
```
Ping the keepalive destination address to make sure that there is connectivity between the two DT switches (keepalive VLANs.)
Enable the ISC link on both switches, and then execute write memory. Assume a2 is configured as switch-interconnect.
```
switch# int a2 enable
switch# write mem
```

From shared DT Keepalive support to point-to-point Keepalive support

When updating software from a software version that does support shared DT keepalive (K.15.03, K.15.04) to a version that supports dedicated point-to-point keepalive (K.15.05), use the following procedure:

Disable the ISC interface and undo the keepalive configuration on both switches. Ignore the warning message that is displayed by the keepalive command while undoing the configuration. Upgrade the software. Assume a2 is configured as switch-interconnect.
```
switch# int a2 disable
switch# no distributed-trunking
peer-keepalive vlan
switch# write mem
```

At switch bootup, create a dedicated VLAN for keepalive and assign only the keepalive link port as a member port of the VLAN. Configure the keepalive destination IP address.

switch# vlan 10 (dedicated point-to-point VLAN interface)
switch(vlan-10)#
switch(vlan-10)# untagged b2 (keepalive link port)
switch(vlan-10)# ip address 10.0.0.1/24
switch(vlan-10)# exit
switch# distributed-trunking
peer-keepalive vlan 10
switch# distributed-trunking
peer-keepalive destination 10.0.0.2

Ping the keepalive destination address to make sure that there is connectivity between the two DT switches (keepalive VLANs.)
Enable the ISC link on both switches, and then execute write memory. Assume a2 is configured as switch-interconnect.
```
switch# int a2 enable
switch# write mem
```