300-410 ENARSI: Implementing Cisco Enterprise Advanced Routing and Services

Both sites must use route target 1:1 for importing and exporting customer_a routes so each VRF accepts the other site's routes. The remote VRF needs a distinct route distinguisher, 1:2, to keep VPN route identities unique; route-target both 1:1 supplies the required symmetric import and export policy. Cisco documents rd as the VRF route distinguisher and route-target both as configuring both import and export route-target communities.

Cisco IOS IP SLA operations remain in the pending state and collect no data until they are scheduled. The ip sla schedule command accepts start-time now to start an operation immediately, allowing tracking output to be generated.

Cisco IOS disables AAA authorization on the console by default, so the RADIUS shell:priv-lvl=15 attribute does not apply to console sessions. Enabling aaa authorization console followed by authorization exec on the line con 0 allows the console to leverage RADIUS authorization. Option D includes both commands, enabling the console to respect the RADIUS privilege level.

BFD's two core benefits are subsecond (typically sub-50ms) failure detection between adjacent forwarding devices and the ability to detect forwarding-path failures directly, independent of and much faster than routing-protocol hello/dead timers. It is not universally supported by every routing protocol and has no relationship to UDLD.

Label Distribution Protocol (LDP) forms label-distribution peer sessions in an MPLS network. MD5 authentication verifies the integrity and origin of LDP peer communications, and a session cannot be established unless both peers use the matching authentication configuration. This prevents unauthorized routers from participating in LDP.