Amer Networks SS3GR24i - Manual (Page 44)

SS3GR24i/SS3GR48i Layer3 Stackable Gigabit Switch User’s Guide
The Time-to-Live (TTL) is the number of gateways the packet is
allowed to cross between the source and destination. This number
is decremented by one when the packet crosses a gateway and
when the TTL reaches zero, the packet is dropped. This helps
reduce network traffic if a loop develops.
Ethernet
Every active Ethernet device has its own Ethernet address
(commonly called the MAC address) assigned to it by the
manufacturer. Ethernet uses 48 bit addresses.
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.
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