Exam 350-401 topic 1 question 222 discussion

Something is missing from this question. In VRRP preempt is configured by default and the priority is set to the default. All in All this question is a disaster.

Default priority for VRRP = 100. Question is vague, not enough information. I think C is more of a valid answer.

Ans: C Priority 100 is default

c answer corect. because by default the router is 100. So I have to decrement some of the routers with a value of 10

My 2 cents... Router with priority 0 will never become master no matter what since it wont be considered during election. Based on presented config we are using default priority 100 and if we lower this value by 100 we get to 0 and router wont be considered. This doesn't meet this requirement "must assume master role". I am going with C

I would say answer C. Although VRRP preempt is enabled by default, it's still possible to use the preempt command. Also, a track configuration is required according to the question. A. Wrong. Decrementing by 100 means a priority of 0, so not in valid range 1 to 254. B. Maybe. Default VRRP priority is already 100, and this option lacks track configuration. C. Correct. The track configuration enables the router to have a priority of 100 or 90. D. Wrong. The 'standby' command is for HSRP, and other value is already default.

The correct command set would be: B. Router(config-if)# vrrp 115 priority 100 This command sets the priority of the router to 100 in VRRP group 115. C. Router(config-if)# vrrp 115 track 1 decrement 10 Router(config-if)# vrrp 115 preempt This command sets up tracking on interface GigabitEthernet0/1, and if the tracked object (likely another interface or route) goes down, it decrements the priority by 10. Preempt is then enabled to allow the router to regain the primary role once it has the highest priority again. So the correct answer is a combination of options B and C.

D can be a good valid answer https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-56896581-339B-407F-9CE2-00566608F35E

Going with "B" assuming other router/s are set below the default priority "100"

VRRP preemption on by default, so A, C, D are red herrings. 'When' it is highest priority, other router could be decrementing based on tracking or static config.

La opcion B es la correcta, si configuras trach 10 para bajar la prioridad, entonces no siempre R1 sera el primario y es lo que esta pidiendo la pregunta.

Looks like B is correct. It says "The router must assume the primary role WHEN it has the highest priority in the group." So the question is not how to make this router primary, but how to make it primary if it has the highest priority. So they are checking only the knowledge of default preemption behavior of vrrp.

preempt is configured by default

The answer is clearly C. You cannot decrement by 100 if the priority is 100 (try it in a lab) and we know the priority is 100 because no priority has been set in the config and therefore the default applies. The best answer is to decrement by 10, making the new priority 90 (we can only assume that the other router is also on the default priority as we haven't been told otherwise and if you've done any Cisco exams before you will know that they expect you to assume and know all the defaults for everything). Preempt is necessary otherwise the primary router won't take control of the VIP when its priority returns to 100.

Option A) with decrement by 100 is wrong for sure. It results in priority 0, and that is not a valid priority value for vrrp. If priority 0 is set, then vrrp gets stuck in "Init" state. See example below: DSW2(config-if)#do sh vrrp Vlan0002 - Group 2 State is Init Virtual IP address is 10.10.2.3 Virtual MAC address is 0000.5e00.0102 Advertisement interval is 1.000 sec Preemption enabled Priority is 0 Track object 1 state Down decrement 100

I think the answer is B. There is no information given about the other router, but by inference it must be set with a higher priority than the one in the question. It would also be set to preempt (by default or by command). Our example is to be the standby. It should take over in the event of a failure of the active rtr, and be preempted when it comes back online. Answer A, decrementing by 100 seems extreme. Answer B, set it default, which should be lower than its partner, making it the standby. Answer C, By decrementing 10, we make it priority 90, but there is no need to preempt, the active one has failed. Answer D, by making it priority 100 and preempting, would make it active unless its partner had a higher priority. If the partner has a higher priority already, preempting should be configured on it, not the standby. Make sense?

There's a lot of missing information however, in order for a router to assume it's highest role in this case "Master" it needs to enable Preemption.