D-Link DES-3326 User Manual - page 102
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
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Switch Management and Operating Concepts
The Ethernet header is 14 octets that include the source and
destination MAC address and a type code.
There is no relationship between the MAC address of a network
node and its IP address. There must be a database of Ethernet
addresses and their corresponding IP addresses.
Different protocol families can be in use on the same network. The
type code field allows each protocol family to have its own entry.
A checksum is calculated and when the packet is received, the
checksum is recalculated. If the two checksums are different, the
packet is dropped.
Figure 5-14. Ethernet Packet Header
When a packet is received, the headers are removed. The Ethernet
Network Interface Card (NIC) removes the Ethernet header and
checks the checksum. It then looks at the type code. If the type
code is for IP, the packet is given to IP. IP then removes the IP