ACSP Routing Protocols & IP Addressing 5 — Questions and Answers
Question 1: Which ArubaOS-CX command verifies that a static route has been successfully installed in the forwarding plane?
- show ip route static
- show running-config | include ip route
- show ip fib (Correct answer)
- show interface statistics
Correct answer: show ip fib
The 'show ip fib' command displays the Forwarding Information Base, confirming routes are programmed into hardware for actual packet forwarding.
Question 2: A network uses the address block 10.0.0.0/8 and needs to create 100 subnets with at least 500 hosts each. Which subnet mask satisfies both requirements?
- /22
- /23 (Correct answer)
- /24
- /25
Correct answer: /23
A /23 provides 512 host addresses (510 usable) and allows up to 128 subnets within 10.0.0.0/8, satisfying both requirements.
Question 3: In BGP, what is the effect of prepending your own AS number multiple times to the AS_PATH attribute before advertising a route?
- It increases the local preference of the route
- It makes the path appear longer, making it less preferred by external peers (Correct answer)
- It prevents the route from being advertised beyond one AS hop
- It marks the route as an aggregate
Correct answer: It makes the path appear longer, making it less preferred by external peers
AS path prepending artificially lengthens the AS_PATH, making the route less preferred by BGP peers that use AS path length as a selection criterion.
Question 4: On ArubaOS-CX, which command enables OSPF on a specific interface rather than using the 'network' command under the OSPF process?
- ip ospf enable
- ospf area 0
- ip ospf area 0.0.0.0 (Correct answer)
- router ospf interface-mode
Correct answer: ip ospf area 0.0.0.0
ArubaOS-CX supports interface-level OSPF activation using 'ip ospf area <area-id>' configured directly on the interface.
Question 5: Which address does an IPv6 host use when communicating with the DHCPv6 server during stateful address assignment?
- The global unicast address assigned by SLAAC
- The link-local address as the source (Correct answer)
- The all-nodes multicast address ff02::1
- The loopback address ::1
Correct answer: The link-local address as the source
DHCPv6 messages are sourced from the host's link-local address since a global unicast address has not yet been assigned.
Question 6: An ArubaOS-CX switch needs to summarize the subnets 172.16.0.0/24, 172.16.1.0/24, 172.16.2.0/24, and 172.16.3.0/24 into a single advertisement. Which summary address is correct?
- 172.16.0.0/21
- 172.16.0.0/22 (Correct answer)
- 172.16.0.0/23
- 172.16.0.0/24
Correct answer: 172.16.0.0/22
The four /24 subnets share the first 22 bits (172.16.0-3), so 172.16.0.0/22 is the correct summary covering all four networks.
Question 7: What is a floating static route in ArubaOS-CX and how is it implemented?
- A route that changes next-hop based on traffic load
- A static route with a higher administrative distance than the primary dynamic route, used as a backup (Correct answer)
- A route that expires after a configurable timeout
- A static route redistributed into a dynamic routing protocol
Correct answer: A static route with a higher administrative distance than the primary dynamic route, used as a backup
A floating static route is configured with an AD higher than the dynamic routing protocol, so it only appears in the RIB when the dynamic route is removed.
ACSP Routing Protocols & IP Addressing 5
Which ArubaOS-CX command verifies that a static route has been successfully installed in the forwarding plane?