Ethernet Loop Detection; Jumbo Frame - ZyXEL Communications MES-2110 Support Notes

MANAGED 8-PORT 10/100 + 2 G DUAL PERSONALITY SWITCH

2.3.4 Ethernet Loop Detection

Ethernet Loop Detection is used to detect Ethernet Loop conditions on active ports.
Ethernet Loops cause broadcast storms and crash the whole network. Set "Protection"
to enable or disable the Ethernet Loop Detection function of the Switch, and enable or
disable it on the specific port. For MAC Address, users can use the default one as the
destination MAC address for Ethernet Loop Detection. The default MAC Address is a
multicast address. Some network switches do not forward packets with unrecognized
multicast MAC address and discard those test packets sent out by the Switch for
Ethernet Loop Detection. In this situation, the function cannot be correctly executed.
Users can set another unicast MAC Address to cope with this condition. If the port is
blocked by Switch for detected loop, it needs to be enabled manually after
Ethernet Loop is removed.

2.3.5 Jumbo Frame

The normal Ethernet frame size can not exceed the boundary of 1522 bytes; any packet
more than this value will be fragmented into smaller datagrams. Jumbo frames extend
this maximum frame size of the Ethernet from 1522 up to 1632 bytes (including Ethernet
headers).
The more the frames that the network device has to handle, the less the TCP
throughput and the more the CPU overhead. By allowing the frame to extend in size
from 1522 to 1632 bytes jumbo frames, the Switch will handle lower number of frames
or datagram's.
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