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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 28 Troubleshooting
LRE Statistics
Table 28-2 LRE Link Statistics
Statistic Type Explanation
Upstream Bandwidth Usage The percentage of the bandwidth used for upstream traff ic, based on the current upstream rate
and actual upstream speed of LRE link.
Downstream Bandwidth
Usage The perce ntage of the bandw idth used for downstream tr affic, base d on the curr ent
downstream rate and actual downstream speed of the LRE link.
Signal to Noise Ratio The amount of increased received signal noise (in decibels) relative to the ambient,
environment, and electromagnetic noise power level that the switch is designed to tolerate
witho ut di scon ne cting fr om the rem ote LR E CPE device. The h igher t he ra ti o, t he m ore
resilient the link.
Upstream Reed-Solomon
Errors The numbe r of detect ed and corre cted data erro rs being re ceived on the switch L RE port.
Reed-Solomon errors result from noise exceeding the noise margin. For short bursts of noise
(such as motor star tup or po wer sur ges) , the Reed- Solomon error cor rection pr ev ents th e loss
of Ethe rnet da ta frames.
The LRE interface corr ects the data bytes that are incorrectly recei ved on the switch LRE port
(up to a designed 8-byte limit). The residual error rate is better than the detection capability
of the Et hernet cycli c redund ancy check (C RC). If the erro r b urst is larger than the co rrectio n
capability of the LRE interface, the Ethernet CRC is used to determine the corrupted frames
and to di scard th em.
Downstream Reed-Solomon
Errors Th e num ber of detec ted and corr ected data err ors bein g rece i v ed on the CPE RJ-11 wa ll por t.
Table 28-3 CPE Ethernet Link Statistics
Counter Description
Transmit
Bytes Total number of bytes transmitted out of this port.
Unicast Frames The total number of well-formed unicast frames sent by a port. It excludes frames sent with
errors or with multicast or broadcast destination addresses.
Multicast Frames The total number o f well-formed multicas t frames sent by a port. It e xcludes frames sent with
error s or with unicast or br oadcast de stination a ddresses.
Broadcas t Frames The tot al number of well- formed br oadcast frames se nt by a port. It exclud es frames sent wit h
errors or with unicast or multicast destination addresses.
Dropp ed Fram es The cou nt of frame s that wer e dropped befo re transm ission.
Pause Frames Incremented for each MAC pause control frame transmitted.
Collision Frames The total number of frames sent without error after having 1 to 15 collisions. It includes
frames of all destination address types and excludes frames discarded because of insuffi cient
resources or late collisions.
One Collision Frames Incremented for each frame that experienced exactly one collision during its transmission
attempt.
Multiple Collisions Incremented f or eac h fram e tha t experien ced mo re than on e c ol lision d urin g its transmission
attempt.