Examine the network exhibit.
A network administrator is implementing OSPF on a VSX pair of aggregation switches: Agg1 and Agg2. VLANs 10 and 20 are connected to layer-2 access switches. Agg-1 and Agg-2 are configured as the default gateway for VLANs 10 and 20, with active gateway enabled.
What is the best practice for configuring OSPF on the aggregation switches and their connection to the Core switch?
When configuring OSPF on a VSX pair of aggregation switches for connections to a core switch, the best practice is to define a layer-2 VSX LAG associated with a layer-3 VLAN interface and enable active forwarding for the Layer-3 VLAN. Active forwarding optimizes layer 3 unicast traffic flowing from the upstream core to the downstream access and prevents bridged traffic from switching over the inter-switch link (ISL), thus minimizing latency and ISL bandwidth usage.
From the tech docs "Active forwarding is an optimization for layer 3 unicast traffic flowing from the upstream (core) to the downstream (access) through the VSX peers (aggregate). "
Answer B : Active forwarding should be enable on every OSPF interface that is a transit network.
should be B. The question is for the connection to the Core switch, should be active forwarding. Active gateway is useful for dowstream VSX LAG to access-switches
Correct Answer: A
Answer D : layer-2 VSX LAG associated with a layer-3 VLAN interface. Enable active forwarding for the Layer-3 VLAN - These are for transit OSPF interface and so forth, it applies. Study guide: Page : 196
Chapter 6 - Advanced OSPF - Using OSPF with VSX. Same Graphic - Description: Transit OSPF interfaces - Layer 2 VSX LAG associated with Layer 3 VLAN (or VLANs), Active Forwarding on VLAN. So Answer D
Note: Interface LAG assignments and VLAN access statements cannot be assigned to an interface simultaneously. An error occurs when saving the MultiEdit configuration, if the vlan access 1 statement is not removed, so you need to define a separate layer 3 interface, and to configure the Active forwarding. Answer: B
https://www.arubanetworks.com/techdocs/AOS-CX/10.07/HTML/5200-7888/Content/Chp_Pre_tra_loss/act-for-10.htm Active forwarding is an optimization for layer 3 unicast traffic flowing from the upstream (core) to the downstream (access) through the VSX peers (aggregate). Active forwarding prevents the bridged traffic from switching over the ISL. It also minimizes latency and the ISL bandwidth B & D Active Forwarding must be enabled on VLAN NOT on Layer 3 VLAN: "The active forwarding, which is set per- VLAN...." [Aruba Networks] C no sense
the right answer is C, with active gateway and not active forwarding
From ACSP learning book Advanced OSPF : "Using OSPF with VSX: - Transit OSPF interfaces : - L2 VSX LAG associated with L3 VLAN (or VLANs) - Active forwarding on VLAN - Interfaces for which VSX pair is default gateway : - Active gateway - Possible passive OSPF interface"
Error, answer D not B