关于第一个问题，升级的问题，确认一下您目前使用的install mode还是bundle mode：
关于Cat3850升级的说明有官方文档可以借鉴，如下所示：
Upgrading from Cisco IOS XE Release 3.x.xE in Install Mode
关于Cat3850升级的说明有官方文档可以借鉴，如下所示：
Upgrading from Cisco IOS XE Release 3.x.xE in Install Mode
Follow these instructions to upgrade from Cisco IOS XE Release 3.x.xE in install mode:
Before you beginNote that you can use this procedure for the following upgrade scenarios:
When upgrading from ... | To... |
Cisco IOS XE Release 3.x.xE | Cisco IOS XE Fuji 16.x.x or Cisco IOS XE Everest 16.x.x or Cisco IOS XE Denali 16.x.x |
The sample output shows upgrade from Cisco IOS XE Release 3.7.3E to Cisco IOS XE Fuji 16.9.1
>>>>>>>>>>后面的信息省略，可以参考如下链接<<<<<<<<<<<
第二个问题，active和standby。
3850的就是active和standby角色，如下是提到的是3850的active和standby选举。可以参考一下
Active and Standby Switch Election and ReelectionAll stack members are eligible to be the active switch or the standby switch. If the active switch becomes unavailable, the standby switch becomes the active switch.
An active switch retains its role unless one of these events occurs:
- The switch stack is reset.
- The active switch is removed from the switch stack.
- The active switch is reset or powered off.
- The active switch fails.
- The switch stack membership is increased by adding powered-on standalone switches or switch stacks.
The active switch is elected or reelected based on one of these factors and in the order listed:
- The switch that is currently the active switch.
- The switch with the highest stack member priority value.
NoteWe recommend assigning the highest priority value to the switch that you prefer to be the active switch. This ensures that the switch is reelected as active switch if a reelection occurs. - The switch with the shortest start-up time.
- The switch with the lowest MAC address.
| Note | The factors for electing or reelecting a new standby switch are same as those for the active switch election or reelection, and are applied to all participating switches except the active switch. |
After election, the new active switch becomes available after a few seconds. In the meantime, the switch stack uses the forwarding tables in memory to minimize network disruption. The physical interfaces on the other available stack members are not affected during a new active switch election and reset.
When the previous active switch becomes available, it does not resume its role as the active switch.
If you power on or reset an entire switch stack, some stack members might not participate in the active switch election. Stack members that are powered on within the same 2-minute timeframe participate in the active switch election and have a chance to become the active switch. Stack members that are powered on after the 120-second timeframe do not participate in this initial election and become stack members. For powering considerations that affect active-switch elections, see the switch hardware installation guide.
As described in the hardware installation guide, you can use the ACTV LED on the switch to see if the switch is the active switch.
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/consolidated_guide/configuration_guide/b_consolidated_3850_3se_cg/b_consolidated_3850_3se_cg_chapter_01010101.html#con_1228109
而3750的就是Master和Slave，这个我理解只是名称不一样而已，总是Master或Active都是“主”，Standby和Slave都是“备”
