7-2CHAPTER 7: BRIDGING EXTENSIONS
See Figure 7-1 for an illustration of the threshold mechanism. For
information on setting this threshold, see the SuperStacka II Switch 2200
Administration Console User Guide.
Multicast/
ReceiveBroadcast
RateStorm
Threshold 400 Packets/SecondFirewall
Time
Multicast/Broadcast Frames Received
Multicast/Broadcast Frames Forwarded
Figure 7-1 Multicast Packet Firewall Threshold Mechanism
IP FragmentationThe maximum length of the information Ţeld in an FDDI packet is 4478
bytes, but the maximum length of the information Ţeld in an Ethernet
packet is only 1500 bytes. Therefore, any packet sourced from an FDDI
station and destined for an Ethernet station must have an information Ţeld
that does not exceed 1500 bytes to bridge the packet in a conventional
fashion.
To overcome this limitation, the Internet Protocol (IP) speciŢes a procedure,
called IP fragmentation. This allows a large FDDI packet to be Ofragmented�
into smaller packets. With IP fragmentation, FDDI and Ethernet stations
connected to a Switch 2200 can communicate using IP even if the FDDI
stations are transmitting packets that would typically be too large to bridge. |
ACEC
