# Internet Protocol Analysis/Multicast

This lesson concludes the Internet layer and looks at multicasting. Activities include using Wireshark to examine multicast and Neighbor Discovery Protocol (NDP) network traffic.

## Readings

* Wikipedia: Multicast
* Wikipedia: Multicast address
* Wikipedia: Internet Group Management Protocol
* Wikipedia: Multicast Listener Discovery
* Wikipedia: Neighbor Discovery Protocol

## Multimedia

* YouTube: Understanding Unicast, Multicast, and Broadcast - CompTIA Network+ N10-005: 1.3
* YouTube: Neighbor Discovery Protocol

## Activities

* Review Wireshark: Internet Group Management Protocol (IGMP).
* Use Wireshark to capture and analyze IPv4 multicast traffic.
* Use Wireshark to capture and analyze IPv6 multicast traffic.
* Use Wireshark to capture and analyze ICMPv6 Neighbor Discovery Protocol (NDP) traffic.
* Consider situations in which a packet analyzer might be used to troubleshoot multicast traffic.

## Lesson Summary

* Multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source.
* Multicast uses network infrastructure efficiently by requiring the source to send a packet only once, even if it needs to be delivered to a large number of receivers. The nodes in the network take care of replicating the packet to reach multiple receivers when necessary.
* In multicast routing, there is always one source and a group of destinations. Broadcasting is a special case of muticasting in which the group contains all hosts.
* IPv4 multicast addresses were originally designated as Class D. The Classless Inter-Domain Routing (CIDR) prefix of this group is 224.0.0.0/4 and includes addresses from 224.0.0.0 through 239.255.255.255.
* The 239.0.0.0/8 range is assigned by RFC 2365 for private use within an organization.
* IPv6 multicast addresses start with ff00::/8.
* Ethernet frames with a value of 1 in the least-significant bit of the first octet of the destination address are treated as multicast (broadcast) frames and are sent to all network hosts. The recipient host Ethernet controller determines by address hashing whether to receive or drop the multicast frame.
* Ethernet IPv4 multicast frames have a destination MAC address starting with 01-00-5E-xx-xx-xx.
* Ethernet IPv6 multicast frames have a destination MAC address starting with 33-33-xx-xx-xx-xx.
* The Internet Group Management Protocol (IGMP) is a communications protocol used by hosts and adjacent routers on IP networks to establish multicast group memberships. IGMP is used on IPv4 networks.
* Multicast management on IPv6 networks is handled by Multicast Listener Discovery (MLD) which uses ICMPv6 messaging in contrast to IGMP's bare IP encapsulation.
* Neighbor Discovery Protocol (NDP) is an Internet layer protocol in the Internet Protocol Suite used with IPv6.
* NDP is responsible for address autoconfiguration of nodes, discovery of other nodes on the link, determining the Link Layer addresses of other nodes, duplicate address detection, finding available routers and Domain Name System (DNS) servers, address prefix discovery, and maintaining reachability information about the paths to other active neighbor nodes.
* NDP defines five ICMPv6 packet types: Router Solicitation, Router Advertisement, Neighbor Solicitation, Neighbor Advertisement, and Redirect.

## Key Terms
### Internet Protocol television (IPTV)

    A system through which television services are delivered using the Internet protocol suite over a packet-switched network such as the Internet, instead of being delivered through traditional terrestrial, satellite signal, and cable television formats.

### Internet Relay Chat (IRC)

    A protocol for real-time Internet text messaging (chat) or synchronous conferencing.

### overlay network

    A computer network which is built on the top of another network where nodes in the overlay can be thought of as being connected by virtual or logical links in the underlying physical network.

### Neighbor Advertisement

    An ICMPv6 NDP packet type that nodes use to respond to a Neighbor Solicitation message.

### Neighbor Solicitation

    An ICMPv6 NDP packet type that nodes use to determine the link-layer address of a neighbor, or to verify that a neighbor is still reachable via a cached link-layer address.

### peer-to-peer (P2P)

    A computer network in which each computer in the network can act as a client or server for the other computers in the network.

### presence information

    A status indicator that conveys ability and willingness of a potential communication partner—for example a user--to communicate.

### Redirect

    An ICMPv6 NDP packet type that routers use to inform hosts of a better first hop for a destination.

### Router Advertisement

    An ICMPv6 NDP packet type that routers use to advertise their presence together with various link and Internet parameters either periodically, or in response to a Router Solicitation message.

### Router Solicitation

    An ICMPv6 NDP packet type that hosts use to request routers to generate Router Advertisements immediately rather than at their next scheduled time.

### streaming media

    Multimedia that is constantly received by and presented to an end-user while being delivered by a provider.

## Review Questions

Click on a question to see the answer.
* Multicast is the delivery of a message or information to _____. Multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source.
* Multicast uses network infrastructure efficiently by requiring the source to send a packet _____, even if it needs to be delivered to a large number of receivers. Multicast uses network infrastructure efficiently by requiring the source to send a packet only once, even if it needs to be delivered to a large number of receivers.
* In multicast routing, there is always _____. In multicast routing, there is always one source and a group of destinations.
* Broadcasting is a special case of muticasting in which _____. Broadcasting is a special case of muticasting in which the group contains all hosts.
* IPv4 multicast addresses were originally designated as Class _____. The Classless Inter-Domain Routing (CIDR) prefix of this group is _____ and includes addresses from _____ through _____. IPv4 multicast addresses were originally designated as Class D. The Classless Inter-Domain Routing (CIDR) prefix of this group is 224.0.0.0/4 and includes addresses from 224.0.0.0 through 239.255.255.255.
* The _____ range is assigned by RFC 2365 for private multicast use within an organization. The 239.0.0.0/8 range is assigned by RFC 2365 for private multicast use within an organization.
* IPv6 multicast addresses start with _____. IPv6 multicast addresses start with ff00::/8.
* Ethernet frames with a value of 1 in the least-significant bit of the _____ are treated as multicast (broadcast) frames and are sent to all network hosts. Ethernet frames with a value of 1 in the least-significant bit of the first octet of the destination address are treated as multicast (broadcast) frames and are sent to all network hosts.
* Ethernet IPv4 multicast frames have a destination MAC address starting with _____. Ethernet IPv4 multicast frames have a destination MAC address starting with 01-00-5E-xx-xx-xx.
* Ethernet IPv6 multicast frames have a destination MAC address starting with _____. Ethernet IPv6 multicast frames have a destination MAC address starting with 33-33-xx-xx-xx-xx.
* The Internet Group Management Protocol (IGMP) is a communications protocol used by hosts and adjacent routers on IPv4 networks to _____. The Internet Group Management Protocol (IGMP) is a communications protocol used by hosts and adjacent routers on IPv4 networks to establish multicast group memberships.
* Multicast management on IPv6 networks is handled by _____ which uses _____ messaging. Multicast management on IPv6 networks is handled by Multicast Listener Discovery (MLD) which uses ICMPv6 messaging.
* Neighbor Discovery Protocol (NDP) is an _____ layer protocol in the Internet Protocol Suite used with IPv6. Neighbor Discovery Protocol (NDP) is an Internet layer protocol in the Internet Protocol Suite used with IPv6.
* NDP is responsible for _____. NDP is responsible for address autoconfiguration of nodes, discovery of other nodes on the link, determining the Link Layer addresses of other nodes, duplicate address detection, finding available routers and Domain Name System (DNS) servers, address prefix discovery, and maintaining reachability information about the paths to other active neighbor nodes.
* NDP defines five ICMPv6 packet types: _____. NDP defines five ICMPv6 packet types: Router Solicitation, Router Advertisement, Neighbor Solicitation, Neighbor Advertisement, and Redirect.

## Assessments

* Lesson Flashcards
* Terms Flashcards
* Quiz