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Good afternoon
We are simulating the vrrp protocol where we have a cisco switch and on the one hand a teltonika RUT950 and a cisco 1800 where when we define a master and a slave they do not understand each other even in the priorities and always get master on both devices.
Can you help?
Teltonika is 110
Cisco is 100

I'm having somewhat similar issues with a RUTX08 and a Cisco router. Observations so far:

  • Using virtual MAC on RUTX08 doesn't work, while Cisco will always use a virtual MAC. When this option is enabled on RUTX08, the vrrpd doesn't even seem to start.
  • When RUT has lower priority than Cisco, in my case it does assume the backup role and shows the Cisco as master in the web interface.
  • However, when RUT has higher priority than Cisco, both end up as master and both will claim the VRRP IP: the Cisco with the common virtual MAC (which is derived from the VRRP ID) and the RUT with its own MAC. The Cisco logs "Duplicate IP" warnings.
Curious about your experience with RUT950: what happens when the Cisco has higher priority? Does the Teltonika router end up in the "Backup" role?

2 Answers

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What are the VRRP priority values set on the CISCO and the RUT?
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After some more testing in my home network, with a Cisco 1841 and a RUTX08, I believe that I found the reason why the Cisco stayed master when the Teltonika has a higher priority: the VRRP daemon on the Teltonika uses an advertisement interval of 2 seconds by default, and my Cisco uses 1 second by default. This can be observed with a packet capture; I checked both with tcpdump on the RUTX08 and with a SPAN port ("monitor session") on the managed switch where both the Teltonika and the CIsco are connected.

After changing the advertisement interval on the Cisco to 2s, both devices assume the correct role (the device with higher priority will become master).

Example config from my Cisco 1841 (I'm testing this in VLAN 11 which is configured on a HWIC-4ESW module in the Cisco, and I'm using VRRP group id 11 on both the RUTX08 and the c1841):

interface Vlan11
 ip address
 vrrp 11 ip
 vrrp 11 timers advertise 2
 vrrp 11 priority 90