L9. Explain the role and functioning of ARP. What is equivalent for IPv6? Flashcards
What is ARP?
The Address Resolution Protocol (ARP) is a protocol used in Ethernet and IP networks to map IP addresses to MAC (Media Access Control) addresses.
What does ARP do?
ARP enables communication between devices within the same network segment by facilitating the resolution of IP addresses to their corresponding MAC addresses, allowing devices to identify the hardware addresses of other devices on the same network segment.
Why is ARP necessary?
For devices to be able to communicate directly with each other at the data link layer.
What is an ARP cache?
An ARP cache or ARP table is a map of IP addresses to MAC addresses for other devices in the local network. By maintaining an ARP cache, devices can quickly retrieve MAC addresses without needing to perform frequent ARP requests.
How does ARP work?
- When a device wants to communicate with another device on the same network segment, it first checks its ARP cache to see if it already has the MAC address corresponding to the destination IP address. If the MAC address is not found in the cache, the device broadcasts an ARP request message to all devices on the local network, asking for the MAC address associated with the destination IP address.
- Upon receiving the ARP request, the device with the matching IP address responds with an ARP reply message containing its MAC address. This reply is unicast to the requesting device.
- The requesting device updates its ARP cache with the newly learned MAC address, allowing it to establish a direct communication link with the destination device.
- Devices maintain an ARP cache or ARP table, which stores mappings of IP addresses to MAC addresses for recently resolved hosts. The ARP cache helps expedite future communication by eliminating the need for ARP requests for frequently accessed hosts.
What does a device do when it wants to communicate with another device on the same network segment?
It first checks its ARP cache to see if it already has the MAC address corresponding to the destination IP address. If the MAC address is not found in the cache, the device broadcasts an ARP request message to all devices on the local network, asking for the MAC address associated with the destination IP address.
What happens when an ARP request is sent?
Upon receiving the ARP request, the device with the matching IP address responds with an ARP reply message containing its MAC address. This reply is unicast to the requesting device.
What does a device do when it receives an ARP reply message?
The device updates its ARP cache with the newly learned MAC address, allowing it to establish a direct communication link with the destination device.
How does a device store MAC addresses to other devices?
Devices maintain an ARP cache or ARP table, which stores mappings of IP addresses to MAC addresses for recently resolved hosts. The ARP cache helps expedite future communication by eliminating the need for ARP requests for frequently accessed hosts.
What is the IPv6 equivalent of ARP?
In IPv6 networks, the equivalent protocol to ARP is the Neighbor Discovery Protocol (NDP). NDP serves similar functions as ARP but is specifically designed for IPv6 networks and incorporates additional features to support IPv6 address resolution and neighbor discovery.
What is NDP?
The Neighbor Discovery Protocol (NDP) is the IPv6 equivalent of ARP
How does NDP differ from ARP?
- Facilitates neighbor discovery, router discovery, and address autoconfiguration in IPv6 networks. It allows devices to discover and maintain a list of neighboring devices on the same link and learn about available routers for off-link communication.
- Includes Router Solicitation (RS) and Router Advertisement (RA) messages, which enable devices to discover routers and configure IPv6 addresses automatically. Routers periodically send RA messages to advertise their presence and configuration parameters to neighboring devices.
- Uses Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages for address resolution and neighbor reachability verification in IPv6 networks. Devices send NS messages to resolve IPv6 addresses to link-layer addresses and receive NA messages in response from neighboring devices.
How are ARP and NDP similar?
ARP and NDP fulfill similar roles by providing mechanisms for address resolution, neighbor discovery, and efficient communication between devices within the same network segment.
What are RS and RA messages?
Router Solicitation (RS) and Router Advertisement (RA) messages enable devices to discover routers and configure IPv6 addresses automatically. Routers periodically send RA messages to advertise their presence and configuration parameters to neighboring devices
What are NS and NA messages?
NDP uses Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages for address resolution and neighbor reachability verification. Devices send NS messages to resolve IPv6 addresses to link-layer addresses and receive NA messages in response from neighboring devices.
