HP 1920 Gigabit Ethernet Switch Series User Manual

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2. If Host A finds no entry for Host B, Host A buffers the packet and broadcasts an ARP request. The
payload of the ARP request contains the following information:
{ Sender IP address and sender MAC address—Host A's IP address and MAC address.
{ Target IP address—Host B's IP address.
{ Target MAC address—An all-zero MAC address.
All hosts on this subnet can receive the broadcast request, but only the requested host (Host B)
processes the request.
3. Host B compares its own IP address with the target IP address in the ARP request. If they are the
same, Host B:
a. Adds the sender IP address and sender MAC address into its ARP table.
b. Encapsulates its MAC address into an ARP reply.
c. Unicasts the ARP reply to Host A.
4. After receiving the ARP reply, Host A:
a. Adds the MAC address of Host B into its ARP table.
b. Encapsulates the MAC address into the packet and sends the packet to Host B.
Figure 217 ARP address resolution process
If Host A and Host B are on different subnets, Host A sends a packet to Host B, as follows:
1. Host A broadcasts an ARP request to the gateway. The target IP address in the ARP request is the
IP address of the gateway.
2. The gateway responds with its MAC address in an ARP reply to Host A.
3. Host A uses the gateway's MAC address to encapsulate the packet, and then sends the packet to
the gateway.
4. If the gateway has an ARP entry for Host B, it forwards the packet to Host B directly. If not, the
gateway broadcasts an ARP request, in which the target IP address is the IP address of Host B.
5. After the gateway gets the MAC address of Host B, it sends the packet to Host B.
ARP table
An ARP table stores dynamic and static ARP entries.

HP 1920 Gigabit Ethernet Switch Series Specifications

General

Brand	HP
Model	1920 Gigabit Ethernet Switch Series
Category	Switch
Language	English