Although the size of the local station table is limited, the total amount of endpoints supported by the whole ACI fabric can be much larger than the size of the local station table. All the endpoints learned on the non-fabric uplinks are stored in the local station table. All the endpoints learned on the fabric uplink ports are kept in the global station table.
Reference: http://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c07-732033.html
When the ingress leaf switch receives the frame, it learns the source MAC and source IP and programs them into the local station table. The leaf switch derives the source EPG based on the VLAN ID or VXLAN VNID. The MAC and IP addresses in the local station table also contain the EPG information and they can be used to derive EPG information for the subsequent packets.
When a leaf switch receives a frame from the host it needs to determine whether the destination IP is inside the fabric or outside the fabric. If the destination IP matches with any /32 host route entry in the global station table, it means the destination is an endpoint inside the fabric and the leave switch already learned the endpoint.
Reference: http://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c07-732033.html
Labels, which are used optionally to group objects such as subjects and EPGs for the purpose of further defining policy enforcement
Reference: http://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-731310.html
A. Addresses of all hosts attached to the ACI fabric.
B. Addresses of all hosts attached directly to the leaf.
C. Global cache of station endpoints.
D. Local cache of station endpoints.
Answer: Option A.
Explanation:
Proxy Station Table contains addresses of ‘all’ hosts attached to the fabric
Reference: http://249459ec2cf8839ca4b8-2690f879103214107f979ba5105d745b.r47.cf2.rackcdn.com/ACI%20Architecture%20Details.pdf (See the table on the right on Page #25).
A. Policy group (source group), forwarding group (tenant, VRF, bridge domain), destination IP address group, and source IP address group.
B. Policy group (source group) forwarding group (tenant, VRF, bridge domain), load-balancing policy, and telemetry policy.
C. Flow mapping of endpoint groups to applications, Layers 3 external identifiers and leaf association of application profiles.
D. Destination IP address group source IP address group, forwarding group, load-balancing policy and telemetry policy.
Answer: Option B.
Explanation:
All Tenant traffic within the Fabric is tagged with an ACI VXLAN (VXLAN) header which identifies the policy attributes of the application end point within the fabric “¢ Policy Group (source group)
“¢ Forwarding Group (Tenant, VRF, Bridge Domain)
“¢ Load Balancing Policy
“¢ Telemetry Policy
Reference: http://www.alcatron.net/Cisco%20Live%202015%20Melbourne/Cisco%20Live%20Content/Data%20Centre/BRKACI-2001%20Integration%20and%20Interoperation%20of%20Existing%20Nexus%20Networks%20into%20an% 20ACI%20Architecture.pdf
Reference: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/1-x/aci-fundamentals/b_ACI-Fundamentals/b_ACIFundamentals_chapter_010100.html#concept_C3EF1E36E8F6406A96A71E605AC175BD