Q14Advanced Addressing and Routing Solutions
A network engineer needs to design an MSDP multicast solution that provides RP resiliency in a network with two separate domains. In addition, multicast sources and receivers must register with their local RP. Which solution must the engineer select?
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Discussion · 11
2
I think D
Two or more RPs are set up with the same IP address (for example, 10.0.0.1) on loopback interfaces. The loopback address should be configured with a 32-bit mask. All the downstream routers are configured so that they know that 10.0.0.1 is the IP address of their local RP. IP routing automatically selects the topologically closest RP for each source and receiver.
https://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/Phase_1/mcstmsdp/mcst_p1.html
B 2
Selected Answer: B
i think it should be B.
https://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/115011-anycast-pim.html
B 2
Selected Answer: B
Option B is the right answer because Anycast RP is a technique that lets multiple RPs share the same IP address. By setting the RP loopback interface with the same IP address/32 in both domains, multicast traffic can be sent to the nearest RP in each domain. This provides RP redundancy and load sharing, making sure that multicast traffic keeps flowing even if one of the RPs fails.
1
Did you mean B?
1
Q174 seems to go against answer B... not sure right now...
1
Yes, I mean B, sorry
B 1
Selected Answer: B
Both can be true and correct because if you check the link:
https://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/115011-anycast-pim.html
Relevant running configurations
Nexus 1 relevant configuration:
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
interface loopback1
ip address 192.168.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface loopback7
ip address 10.1.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface Ethernet9/2
ip address 10.7.7.1/24
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface Ethernet9/3
ip address 172.16.1.2/24
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
1
Nexus 2 relevant configuration:
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
interface loopback1
ip address 192.168.2.2/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface loopback7
ip address 10.1.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface Ethernet9/2
ip address 10.7.7.2/24
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
-----------------------------
This is exactly what we need here:
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
(10.1.1.1 is the "loopback 7" for both of the devices -> Which is the same -> Question 174)
(192.168.1.1 / 192.168.2.2 is their "Loopback 1" which should be a diverse loopback address for each RP -> Question 181)
B 1
Selected Answer: B
as from requirement MSDP must also provide RP resilience, seems the best solution is to configure Anycast RP so B is correct
B 1
Selected Answer: B
Answer is B
https://techhub.hpe.com/eginfolib/networking/docs/switches/7500/5200-1936a_ip-multi_cg/content/495505225.htm#:~:text=One%20or%20more%20pairs%20of,RPs%20by%20these%20MSDP%20peers.&text=As%20shown%20in%20Figure%2057,on%20any%20PIM%2DSM%20router.
1
How can you say here that they need to use the same loopback address, and in 174 use unique loopback addresses? Am I missing something?