Rockwell Automation Publication 1783-UM001B-EN-P - May 2010 37
Diagnostics Chapter 3
• RxFCS Errors - Packets received (between 645 and 1522 octets) with FCS
(frame check sequence) not matching
• RXGoodPkts - Octets received with no errors
• RXDrop Pkts - Packets dropped due to lack of resources (bandwidth,
input buffer)
• RxUnicast Pkts - Unicast packet received (only one receiving host)
• RxMulticast Pkts - Multicast packets received (many receiving hosts)
• RxBroadcast Pkts - Received by all hosts on the network
• RxSAChanges - Number of times the Source address of a good packet has
changed value. A count greater than 1 indicates a repeater based network
• RxFragments - Packets received less than 64 octets
• RxExcessSizeDisc - Packets received greater than 1536 octets and
discarded due to excessive length
• RxSymbolError - Invalid data symbol detected
IGMP Report
The IGMP protocol manages membership in IP multicast groups. Only hosts in
that group receive the packet. The IGMP protocol prevents a multicast packet
from behaving like a broadcast (transmitted to all network hosts).
The switch manages the task of forming a table of IGMP groups and hosts
belonging to those groups. The table can be displayed by selecting Diagnostics
and IGMP report.