How is MSDP used to interconnect multiple PIM-SM domains?
How is MSDP used to interconnect multiple PIM-SM domains?
MSDP allows a rendezvous point to dynamically discover active sources outside of its domain. This enables multiple PIM-SM domains to exchange information about active multicast sources, facilitating the efficient forwarding of multicast traffic across domain boundaries.
From Cisco Document, matches A exactly https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054452 Benefits of Using MSDP to Interconnect Multiple PIM-SM Domains •Allows a rendezvous points (RP) to dynamically discover active sources outside of its domain.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf Page 2 : Benefits of Using MSDP to Interconnect Multiple PIM-SM Domains • Allows a rendezvous point (RP) to dynamically discover active sources outside of its domain
A Benefits of Using MSDP to Interconnect Multiple PIM-SM Domains •Allows a rendezvous points (RP) to dynamically discover active sources outside of its domain. •Introduces a more manageable approach for building multicast distribution trees between multiple domains.
https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html Allows a rendezvous point (RP) to dynamically discover active sources outside of its domain.
Answer A "Benefits of Using MSDP to Interconnect Multiple PIM-SM Domains - Allows a rendezvous point (RP) to dynamically discover active sources outside of its domain. - Introduces a more manageable approach for building multicast distribution trees between multiple domains." https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf
Both A and C mentioned in your resource. That said, the question appears to ask HOW it is used, rather than what components are required. MSDP is used to allow RPs to dynamically discover active sources outside of its domain. To do this, MSDP requires BGP/mpBGP.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf It is 100% C
The question is how not what are the benefits MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html (M)BGP is not required in default MSDP peer scenarios or in scenarios where only one MSDP peer is configured. For more information, see the Configuring a Default MSDP Peer section. and MSDP is a mechanism to connect multiple PIM-SM domains. The purpose of MSDP is to discover multicast sources in other PIM domains so the answer is A
The question is saying multiple so it going to be more than 1 peer and BGP will be needed at that point. A is a benefit of running MSDP but it will require BGP
Agree.
Why would one MSDP peer be configured, when the purpose of MSDP is connect multiple PIM-SM domains. Doesn't this mean each PIM-SM domain will need at least one MSDP peer?
Agree.
SA request messages are used to request a list of active sources for a specific group. These messages are sent to an MSDP SA cache that maintains a list of active (S, G) pairs in its SA cache -> Answer "MSDP SA request messages are used to request a list of active sources for a specific group" is correct. SA response messages are sent by the MSDP peer in response to an SA request message. SA response messages contain the IP address of the originating RP and one or more (S, G) pairs of the active sources in the originating RP’s domain that are stored in the cache -> Answer "MSDP messages are used to advertise active sources in a domain" is not correct as it should be "SA response messages are used to advertise active sources in a domain" (not MSDP messages). Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
A. Taken 1:1 from the original Cisco Documentation: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
And C is also 1:1 in the same docu. @Mod: I assume that the question should state "choose two".
Indeed it does say that, but.. "Note (M)BGP is not required in MSDP mesh group scenarios. For more information about MSDP mesh groups, see the Configuring an MSDP Mesh Group section. Note (M)BGP is not required in default MSDP peer scenarios or in scenarios where only one MSDP peer is configured. For more information, see the Configuring a Default MSDP Peer section."
Indeed it does say that, but.. "Note (M)BGP is not required in MSDP mesh group scenarios. For more information about MSDP mesh groups, see the Configuring an MSDP Mesh Group section. Note (M)BGP is not required in default MSDP peer scenarios or in scenarios where only one MSDP peer is configured. For more information, see the Configuring a Default MSDP Peer section."
MSDP is a mechanism to connect multiple PIM-SM domains. The purpose of MSDP is to discover multicast sources in other PIM domains.
Is that answer from ChatGPT lol
He is telling you the answer is A because even B and C are correct only A explains how is MSDP used
It is B bro. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
It is B bro. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
He is telling you the answer is A because even B and C are correct only A explains how is MSDP used
It is B bro. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
It is B bro. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
Allows a rendezvous point (RP) to dynamically discover active sources outside of its domain. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
Answer is A Straight from Cisco White Pages https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
A is the answer. The purpose of MSDP is to discover multicast sources in other PIM domains. The main advantage of MSDP is that it reduces the complexity of interconnecting multiple PIM-SM domains by allowing PIM-SM domains to use an interdomain source tree (rather than an common shared tree). When MSDP is configured in a network, RPs exchange source information with RPs in other domains. An RP can join the interdomain source tree for sources that are sending to groups for which it has receivers. The RP can do that because it is the root of the shared tree within its domain, which has branches to all points in the domain where there are active receivers. When a last-hop router learns of a new source outside the PIM-SM domain (through the arrival of a multicast packet from the source down the shared tree), it then can send a join toward the source and join the interdomain source tree. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html
Pay attention to the Question: "How is MSDP used"? it does not ask 'WHAT(protocol) is MSDP DEPENDS'
For me, I see that answer C is correct. Check this reference which mentioned that the MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
A,B,C, and D are all mentioned in https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html "How is MSDP used" could be C or D. I vote for C
I'm sorry. What I wanted to say is that for "How is MSDP used", B or D make more sense. I vote for D.
In that same article under a note quotes : MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. So C is the absolute best option
In that same article under a note quotes : MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. So C is the absolute best option
MSDP provides a mechanism to connect multiple PIM Sparse-Mode (PIM-SM) domains together. Each PIM-SM domain uses its own independent Rendezvous Point(s) (RPs), and does not have to depend on RPs in other domains.
The Multicast Source Discovery Protocol (MSDP) defines a topology connecting Protocol Independent Multicast sparse mode (PIM-SM) domains. MSDP provides inter-domain access to multicast sources in all domains by enabling all Rendezvous Points (RPs) to discover multicast sources outside of their domain
https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html Note MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation
C ... like timtgh bad question
C ... like timtgh bad question
https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html Note MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation
C ... like timtgh bad question
C ... like timtgh bad question
A is true, but it's a benefit. Questions asks HOW, and C is true for normal operations, only exception is MSDP group mesh. MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-AEEC123A-A9DF-48EC-94B1-638E04F2FA8F
Originally I was thinking the same way you were, but when I kept reading thats when it clicked. The answer is indeed A. MSDP is used so that RPs can discover sources outside of the domain. BGP just allows for interdomain operability but its not defining exactly what MSDP is used for.
"Before configuring MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP).", so that answer C is what the question wants to ask. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387
The correct answer should be C. "With the exception of a single MSDP peer, default MSDP peer, and MSDP mesh group scenarios, all MSDP peers must be configured to run BGP prior to being configured for MSDP." https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf
A is correct answer 100%
answer is A
C -> MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. Figure 1 illustrates MSDP operating between two MSDP peers. PIM uses MSDP as the standard mechanism to register a source with the RP of a domain. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html
D - MSDP is used to advertise sources between RPs in for Anycast operation. Since RPs are statically defined, the routers should all be in one domain.
AC according to mentioned document: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html The question should state "choose two"!
I think it is a the question is how is it used not how it functions
The purpose of MSDP is to discover multicast sources in other PIM domains.
MSDP provides inter-domain access to multicast sources in all domains by enabling all Rendezvous Points (RPs) to discover multicast sources outside of their domains
Multicast Source Discovery Protocol- MSDP, If listeners exist, it triggers a PIM join into the source domain towards the data source. In a peering relationship, one MSDP peer listens for new TCP connections on the well-known port 639.
MSDP operates independently of BGP (Border Gateway Protocol). While BGP can be used in some scenarios to carry MSDP messages between MSDP peers in different domains, it is not a strict dependency for MSDP to function. MSDP primarily relies on TCP connections between MSDP peers to exchange information about active multicast sources across different PIM-SM domains. Therefore, option C is not the most accurate description of how MSDP is used to interconnect multiple PIM-SM domains.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html according to the link, I paste somet content here: 1. Allows a rendezvous point (RP) to dynamically discover active sources outside of its domain. ==> matches option A 2. SA request messages are used to request a list of active sources for a specific group. ==> matches option B 3. MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. ==> matches option C 4. SA messages are used to advertise active sources in a domain. ==> it's SA message, not all 4 types of MSDP messages, so it's wrong Is there any possibility that the question asked you to select an INCORRECT option?
SA Request Messages SA request messages are used to request a list of active sources for a specific group. These messages are sent to an MSDP SA cache that is maintains a list of active (S, G) pairs in its SA cache. Join latency can be reduced by using SA request messages to request the list of active sources for a group instead of having to wait up to 60 seconds for all active sources in the group to be readvertised by originating RPs. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html
Selected Answer B. ( Not A :) )
it´s A MSDP (Multicast Source Discovery Protocol) facilitates the interconnection of multiple PIM-SM (Protocol Independent Multicast - Sparse Mode) domains. It enables rendezvous points (RPs) in different PIM-SM domains to exchange information about active multicast sources. This allows an RP in one domain to dynamically discover active sources in other domains, facilitating efficient multicast traffic forwarding across domain boundaries.
Based on this IP Multicast Guide from Cisco the answer is C Prerequisites for Using MSDP to Interconnect Multiple PIM-SM Domains. Before you configure MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP) https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
A İS ANSWER
A B C are all mentioned in the https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054387. if the domain is stub, it can use default peer-RPF and don't use BGP, use static and default route to connect domains. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-C32DB31A-7F19-4C25-A33F-C1D7E91443BB. it seems the C is more exact.
sorry, it seems the A is more exact.
The question mentions "interconnect domains" MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. Answer is C:
sorry, A is the answer as the question asks "How is MSDP used"
This is about how MSDP used to interconnect PIM-SM domains. BGP is the answer.
This is D
Bad question. All the answers are true. But we can only pick one.
All four are true, but the question is asking "How." The step absolutely required is the BGP. The other choices are specific functionalities. I would choose C because the others can't exist without it. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf
As per cisco, should be A, page number 2: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-3s/asr903/imc-pim-xe-3s-asr903-book/imc_msdp.pdf
The best option is B
Explanation SA request messages are used to request a list of active sources for a specific group. These messages are sent to an MSDP SA cache that maintains a list of active (S, G) pairs in its SA cache -> Answer C is correct. SA response messages are sent by the MSDP peer in response to an SA request message. SA response messages contain the IP address of the originating RP and one or more (S, G) pairs of the active sources in the originating RP’s domain that are stored in the cache -> Answer D is not correct as it should be “SA response messages are used to advertise active sources in a domain” (not MSDP messages). Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16- book/imc-msdp-im-pim-sim.html
C -> MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups. Figure 1 illustrates MSDP operating between two MSDP peers. PIM uses MSDP as the standard mechanism to register a source with the RP of a domain. https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html
MSDP provides a mechanism to connect multiple PIM Sparse-Mode (PIM-SM) domains together. Each PIM-SM domain uses its own independent Rendezvous Point(s) (RPs), and does not have to depend on RPs in other domains.
I think it c.
Before you configure MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP). https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
I think Bambju found the solution.....
Selected Answer: A https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
B is correct source from Cisco
Correction , most suitable is Answer A https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
Prerequisites for Using MSDP to Interconnect Multiple PIM-SM Domains Before you configure MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP).
I'm struggling with this because you can't run MSDP between domains without BGP so C is completely valid. However A is an accurate description.
Is there MSDP in the Cert. Guide? Surely not in the blueprint
Nope, C: Prerequisites for Using MSDP to Interconnect Multiple PIM-SM Domains Before you configure MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP).
MSDP depends on BGP or multiprotocol BGP (MBGP) for interdomain operation. We recommended that you run MSDP on RPs sending to global multicast groups.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-56896581-339B-407F-9CE2-00566608F35E
answer is clearly A
The correct answer is: A. MSDP allows a rendezvous point to dynamically discover active sources outside of its domain. MSDP enables multiple PIM-SM domains to exchange information about active multicast sources, allowing each domain's Rendezvous Point (RP) to dynamically discover sources located in other domains. This facilitates interdomain multicast communication by allowing multicast traffic from sources in one domain to be distributed to receivers in other domains.
Prerequisites for Using MSDP to Interconnect Multiple PIM-SM Domains. Before you configure MSDP, the addresses of all MSDP peers must be known in Border Gateway Protocol (BGP) https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html
The only required task to use MSDP to interconnect multiple PIM-SM domains is configuring an MSDP Peer. "All MSDP peers must be configured to run BGP before being configured for MSDP." The other statements are correct! https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054697
If you read the Link that was shared by Daaid, https://www.cisco.com/c/en/us/td/docs/ios/12_4t/ip_mcast/configuration/guide/mctmsdp.html#wp1054452 And ten we review The Answers in reverse order. D is Correct - MSDP messages are used to advertise Active sources but this doesn't addrress the "Interconnect" part of the question. C is also correct. According to this document MSDP does require BGP or MBGP but this is a requirement of MSDP and again doesn't address the "Interconnect" issue. B is wrong - MSDP uses SA messages to advertise active sources, not to request a list of sources. A is also Correct and this directly addresses the issue of Interconnecting Multiple PIM-SM Domains
What a brutal question but also a great way to understand the components of MSDP, a protocol that I am unlikely to use or seen to be used ever: MSDP is a mechanism to connect multiple PIM-SM domains, it's purpose is to discover multicast sources in other PIM-SM domains. Allows a RP to dynamically discover active sources outside of its domain. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-4B201DB3-2C27-4F98-977A-A1AE9DC39C21
How to Use MSDP to Interconnect Multiple PIM-SM Domains Perform the following tasks to use MSDP to interconnect multiple PIM-SM domains. The first task is required; all other tasks are optional.