HP Virtual Connect Flex-10 10Gb Ethernet Module for c-Class BladeSystem User Manual

Page 145

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Port Statistic

Description

otherwise well-formed.

EtherStatsJabbers

The total number of packets received that were longer than 1518

octets (excluding framing bits, but including FCS octets), and had
either a bad FCS with an integral number of octets (FCS Error) or a

bad FCS with a non-integral number of octets (Alignment Error). This

definition of jabber is different than the definition in IEEE-802.3 section
8.2.1.5 (10BASE5) and section 10.3.1.4 (10BASE2). These

documents define jabber as the condition where any packet exceeds

20 ms. The allowed range to detect jabber is between 20 ms and 150
ms.

EtherStatsOctets

The total number of octets of data (including those in bad packets)

received on the FCS octets). This object can be used as a reasonable
estimate of Ethernet utilization. If greater precision is required, the

StatsPkts and StatsOctets objects should be sampled before and after a

common interval. The differences in the sampled values are Pkts and
Octets, respectively, and the number of seconds in the interval is

Interval. These values are used to calculate the Utilization as follows:

Utilization = [(Pkts * (9.6 + 6.4) + (Octets * .8)) / (Interval *
10,000)]. The result of this equation is the value Utilization which is

the percent utilization of the Ethernet segment on a scale of 0 to 100

percent.

EtherStatsPkts

The total number of packets (including bad packets, broadcast
packets, and multicast packets) received.

EtherStatsCollisions

The best estimate of the total number of collisions on this Ethernet
segment. The value returned depends on the location of the RMON

probe. Section 8.2.1.3 (10BASE-5) and section 10.3.1.3 (10BASE-2)
of IEEE standard 802.3 states that a station must detect a collision, in

the receive mode, if three or more stations are transmitting

simultaneously. A repeater port must detect a collision when two or

more stations are transmitting simultaneously. Therefore, a probe
placed on a repeater port could record more collisions than a probe

connected to a station on the same segment would. Probe location

plays a much smaller role when considering 10BASE-T.
14.2.1.4 (10BASE-T) of IEEE standard 802.3 defines a collision as the

simultaneous presence of signals on the DO and RD circuits
(transmitting and receiving at the same time). A 10BASE-T station can

only detect collisions when it is transmitting. Therefore, probes placed

on a station and a repeater should report the same number of
collisions. Additionally, an RMON probe inside a repeater should

ideally report collisions between the repeater and one or more other

hosts (transmit collisions as defined by IEEE 802.3k) plus receiver
collisions observed on any coax segments to which the repeater is

connected.

EtherStatsCRCAlignErrors

The total number of packets received that had a length (excluding
framing bits, but including FCS octets) of between 64 and 1518

octets, inclusive, but had either a bad FCS with an integral number of

octets (FCS Error) or a bad FCS with a non-integral number of octets
(Alignment Error).

TXNoErrors

All packets transmitted without errors, less oversized packets.

RXNoErrors

All packets received without errors, less oversized and undersized

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