nerdexam
Cisco

300-620 · Question #199

How is broadcast forwarded in Cisco ACI Multi-Pod after ARP flooding is enabled?

The correct answer is C. Broadcast frames are forwarded inside the pod and across the IPN using the multicast address. In Cisco ACI Multi-Pod, when ARP flooding is enabled, broadcast frames are efficiently forwarded across the Inter-Pod Network (IPN) and within pods using an underlying multicast addressing mechanism.

Multi-Pod and Multi-Site

Question

How is broadcast forwarded in Cisco ACI Multi-Pod after ARP flooding is enabled?

Options

  • AIngress replication is used on the spines to forward broadcast frames in the IPN infrastructure.
  • BWithin a pod, the ingress leaf switch floods the broadcast frame on all fabric ports.
  • CBroadcast frames are forwarded inside the pod and across the IPN using the multicast address
  • DFor the specific bridge domain, all spines forward the broadcast frames to IPN routers.

How the community answered

(24 responses)
  • A
    13% (3)
  • B
    4% (1)
  • C
    75% (18)
  • D
    8% (2)

Why each option

In Cisco ACI Multi-Pod, when ARP flooding is enabled, broadcast frames are efficiently forwarded across the Inter-Pod Network (IPN) and within pods using an underlying multicast addressing mechanism.

AIngress replication is used on the spines to forward broadcast frames in the IPN infrastructure.

While ingress replication is used in some ACI scenarios, the primary mechanism for forwarding broadcast frames across the IPN in Multi-Pod, especially with ARP flooding, is underlay multicast.

BWithin a pod, the ingress leaf switch floods the broadcast frame on all fabric ports.

Flooding within a pod occurs, but the question specifically asks how broadcast is forwarded in Multi-Pod, implying across pods, and refers to the overall forwarding mechanism, not just the local pod behavior.

CBroadcast frames are forwarded inside the pod and across the IPN using the multicast addressCorrect

When ARP flooding is enabled in Cisco ACI Multi-Pod, broadcast frames, such as ARP requests, are forwarded by converting them to multicast traffic within the ACI fabric. These multicast packets are then encapsulated and transmitted across the Inter-Pod Network (IPN) using the underlying multicast routing infrastructure. This method efficiently scales broadcast forwarding across multiple pods without relying on widespread flooding.

DFor the specific bridge domain, all spines forward the broadcast frames to IPN routers.

Spines are involved in forwarding, but the specific mechanism for efficient cross-IPN broadcast forwarding with ARP flooding relies on the fabric's multicast addressing scheme, not just generic forwarding by all spines.

Concept tested: Cisco ACI Multi-Pod BUM forwarding with ARP flooding

Source: https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-739989.html

Topics

#Multi-Pod#broadcast forwarding#ARP flooding#IPN#multicast address

Community Discussion

No community discussion yet for this question.

Sign up to join the discussion
Full 300-620 Practice