Cabletron Systems NB30 Manual De Usuario

Bridge Spanning Tree

3-17

NB-30 Bridging

The total number of frames received by the port that had Cyclical Redundancy 
Check (CRC) errors. 

The number of frames received by the port from the network that were 
misaligned Ñ that is, in which a byte of data in the packet contained less than 
8 bits. 

The number of frames that were received by the port which were too large for the 
network. A giant exceeds the maximum Ethernet frame size of 1518 bytes 
(excluding preamble).

These Þelds display the number of packets that were discarded at one of the 
bridge ports. Note that the Inbound count applies to the Ethernet port only.

Displays the number of packets received by the port which were discarded for 
any reason (lack of buffer space, the frame time-to-live was exceeded, or the 
packet was too large for the network). 

The number of frames that were discarded at the port speciÞcally because the 
NB-30Õs frame buffer was unable to keep up with the rate of trafÞc on the 
network.

The number of frames that were discarded at the port because the frameÕs 
time-to-live (the maximum time for forwarding) was exceeded before it could be 
transmitted by the port.

The Bridge Spanning Tree window allows you to display and modify the NB-30Õs 
bridge port information and protocol parameters relating to the Spanning Tree 
Algorithm. 

In a network design with multiple transparent bridges placed in parallel (i.e., 
attached to the same local network segment), only a single bridge should forward 
data through the LAN, leaving the remaining bridges on the segment in a standby 
state so that another can assume the bridging responsibility (should the currently 
active bridge go down). The Spanning Tree Algorithm (STA) is the method that 
bridges use to communicate with each other to ensure that only a single data 
route exists between any two end stations.