To prevent traffic drop after the aggregation layer comes online, which linkup delay timer configuration is recommended?

To prevent traffic drop after the aggregation layer comes online, which linkup delay timer configuration is recommended?

• A. Configure the linkup delay timer to 240 seconds to double the amount of time for the initial phase to sync
• B. Configure the linkup delay timer to exclude LAGs 101, and 102, which will allow time for routing adjacencies to form and to learn upstream routes
• C. Configure the linkup delay timer to include LAGs 101 and 102, Which will allow time for routing adjacencies to form and to learn upstream routes
• D. Configure the linkup delay timer to 120 seconds, which will allow the right amount of time for the initial phase to sync

Answer: (C)

The main idea is to give the network time to converge on the essential core paths before traffic starts flowing again. When the aggregation layer comes online, you don’t want traffic to be forwarded while routing adjacencies with upstream devices are still forming and routes are being learned. The linkup delay timer acts as a safety window to pause forwarding until these critical links are ready. Including the uplink LAGs 101 and 102 in the delay ensures this window covers the convergence time of the core-facing connections. Those LAGs are the paths to the upstream routers and core, so waiting for them to come up means routing adjacencies can form and upstream routes can be learned before traffic is moved through the new aggregation layer. This minimizes the risk of traffic drops during the transition. Excluding the up-link LAGs would shorten or bypass that necessary window, increasing the chance of drops as the core and routing protocols converge. The exact duration should match your environment’s convergence time, but the critical factor is ensuring the core-facing LAGs are part of the delay. So, configuring the linkup delay timer to include the two uplink LAGs provides the right coordination between link readiness and routing convergence, making it the best choice.

The main idea is to give the network time to converge on the essential core paths before traffic starts flowing again. When the aggregation layer comes online, you don’t want traffic to be forwarded while routing adjacencies with upstream devices are still forming and routes are being learned. The linkup delay timer acts as a safety window to pause forwarding until these critical links are ready.

Including the uplink LAGs 101 and 102 in the delay ensures this window covers the convergence time of the core-facing connections. Those LAGs are the paths to the upstream routers and core, so waiting for them to come up means routing adjacencies can form and upstream routes can be learned before traffic is moved through the new aggregation layer. This minimizes the risk of traffic drops during the transition.

Excluding the up-link LAGs would shorten or bypass that necessary window, increasing the chance of drops as the core and routing protocols converge. The exact duration should match your environment’s convergence time, but the critical factor is ensuring the core-facing LAGs are part of the delay.

So, configuring the linkup delay timer to include the two uplink LAGs provides the right coordination between link readiness and routing convergence, making it the best choice.