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QID:NG16 IGMP - Routing Protocol or Communications Protocol? - joshuad31 - 03-22-2010
Hello,
IGMP is a communications protocol. It is not a routing protocol. You are also missing one correct answer which is IGMP snooping runs on Layer 3 routers. This is indeed correct. See link
http://en.wikipedia.org/wiki/Internet_Group_Management_Protocol
25. (QID:NG16) Which three statements are true about the Internet Group Management Protocol (IGMP)? (Choose three)
IGMP is used to register individual hosts with a multicast group.
IGMP is a multicast routing protocol that makes packet-forwarding decisions independent of other routing protocols such as EIGRP.
IGMP version 3 enables a multicast receiving host to specify to the router which sources it should forward traffic from.
IGMP messages are IP datagrams with a protocol value of 2, destination address of 224.0.0.2, and a TTL value of 1.
There are three IGMP modes: dense mode, sparse mode, and sparse-dense mode.
IGMP snooping runs on Layer 3 routers.
Correct Answer:
IGMP is a multicast routing protocol that makes packet-forwarding decisions independent of other routing protocols such as EIGRP.
IGMP is used to register individual hosts with a multicast group.
IGMP version 3 enables a multicast receiving host to specify to the router which sources it should forward traffic from.
Re: QID:NG16 IGMP - Routing Protocol or Communications Protocol? - forumsupport - 03-24-2010
IGMP runs on routers; IGMP snooping runs on layer 2 switches.
http://www.ciscosystems.com/en/US/docs/switches/lan/catalyst4500/12.1/8aew/configuration/guide/multi.pdf
Re: QID:NG16 IGMP - Routing Protocol or Communications Protocol? - joshuad31 - 03-24-2010
Ok the document you linked states specifically that:
IGMP (on a router) sends out periodic general IGMP queries. Therefore it does operate on a layer 3 router. That statement is true. The statement that IGMP is a routing protocol is false. It is a communications protocol. It does not route traffic but instead it allows hosts to subscribe to multicasts by sending requests at Layer 2.
Re: QID:NG16 IGMP - Routing Protocol or Communications Protocol? - forumsupport - 03-25-2010
1. You have to select three correct answers - which is not possible if you omit the "multicast routing protocol" option. I think a routing protocol is also a communication protocol.
2. Sometimes you have to settle with minor differences. After all boss is always right, and Cisco is the boss here.