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StackWise Questions 4

November 17th, 2018 in SWITCH 300-115 Go to comments

Question 1

Question 2

Question 3

Question 4

Question 5


A StackWise Virtual link carries data traffic and in-band control traffic between two switches. A StackWise Virtual link transports control messages between two switches. Messages include protocol messages that are processed by the Cisco StackWise Virtual active switch, but received or transmitted by interfaces on the Cisco StackWise Virtual standby switch. Control traffic also includes module programming between the Cisco StackWise Virtual active switch and the switching modules on the Cisco StackWise Virtual standby switch.

Cisco StackWise Virtual transmits data traffic over a StackWise Virtual link under the following circumstances:
+ Layer 2 traffic flooded over a VLAN (even for dual-homed links).
+ Packets processed by software on the Cisco StackWise Virtual active switch where the ingress interface is on the Cisco StackWise Virtual standby switch.
+ The packet destination is on the peer switch, as described in the following examples:
   + Traffic within a VLAN where the known destination interface is on the peer switch.
   + Traffic that is replicated for a multicast group and the multicast receivers are on the peer switch.
   + The known unicast destination MAC address is on the peer switch.
   + The packet is a MAC notification frame destined for a port on the peer switch.

A StackWise Virtual link also transports system data, such as NetFlow export data and SNMP data, from the Cisco StackWise Virtual standby switch to the Cisco StackWise Virtual active switch.

Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/16-6/configuration_guide/b_166_stck_mgr_ha_3850/b_166_stck_mgr_ha_3850_chapter_010.html

Question 6


From the quote below, we can say the stackwise version must match.

“Switches with the same major version number but with a different minor version number as the stack master are considered partially compatible. When connected to a switch stack, a partially compatible switch enters version-mismatch (VM) mode and cannot join the stack as a fully functional member. The software detects the mismatched software and tries to upgrade (or downgrade) the switch in VM mode with the switch stack image or with a tar file image from the switch stack flash memory. The software uses the automatic upgrade (auto-upgrade) and the automatic advise (auto-advise) features.”

Reference: https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html

Question 7

Question 8

Question 9

Question 10


Stack Master Election
How is the stack master elected?
These rules have been defined to determine which unit within a stack is chosen as the master. When switches are added or stacks are merged, the master will be chosen based on these rules, in the order specified:
1. The switch that is currently the stack master.
Note: When stacks merge, the elected stack master would have been the master of one of the merged stacks.
Note: When stacks partition, the stack master of the original stack will be the master of its partition.
2. The switch with the highest stack member priority value.
Note: Cisco recommends that you assign the highest priority value to the switch that you prefer to be the stack master. This ensures that the switch is re-elected as stack master if a re-election occurs.
3.The switch that uses the non-default interface-level configuration.
4. The switch with the higher Hardware/Software priority.

Reference: https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html#anc11

Therefore the answer should be A, not B (yes, very surprised!)

  1. jury
    August 8th, 2019

    Question 5, why is A not correct,
    where exactly packets are processed,

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