Viewing RMON Statistics

Before you begin

You must enable RMON statistics collection.

About this task

Use the following procedure to view RMON statistics for each port.

Procedure

In the Device Physical View, select a port.
In the navigation pane, expand the Configuration > Graph folders.
Click Port.
Click the RMON tab.
Select the statistics you want to graph.
Select a graph type:
- bar
- pie
- chart
- line

RMON Field Descriptions

The following table describes fields on the RMON tab.


Name	Description
Octets	Specifies the number of octets of data (including those in bad packets) received on the network (excluding framing bits but including FCS octets). You can use this object as a reasonable estimate of Ethernet utilization. If additional precision is desired, sample the Pkts and Octets objects before and after a common interval. The differences in the sampled values are Pkts and Octets, and the number of seconds in the interval is Interval. These values are used to calculate the Utilization as follows: Pkts * (9.6+6.4) + (Octets * .8) Utilization = ...................................... 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.
Pkts	Specifies the number of packets (including bad packets, broadcast packets, and multicast packets) received.
BroadcastPkts	Specifies the number of good packets received that were directed to the broadcast address. This number does not include multicast packets.
MulticastPkts	Specifies the number of good packets received that were directed to a multicast address. This number does not include packets directed to the broadcast address.
CRCAlignErrors	Specifies the number of packets received that had a length (excluding framing bits, but including FCS octets) between 64 and 1518 octets, inclusive, but had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a nonintegral number of octets (Alignment Error).
UndersizePkts	Specifies the number of packets received that were less than 64 octets long (excluding framing bits, but including FCS octets) and were otherwise well formed.
OversizePkts	Specifies the number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets) and were otherwise well formed.
Fragments	Specifies the number of packets received that were less than 64 octets in length (excluding framing bits but including FCS octets) and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a nonintegral number of octets (Alignment Error). It is entirely normal for Fragments to increment because it counts both runs (which are normal occurrences due to collisions) and noise hits.
Collisions	Specifies the best estimate of the 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 transmit simultaneously. Thus, a probe placed on a repeater port can record more collisions than a probe connected to a station on the same segment. 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. Thus, probes placed on a station and a repeater reports the same number of collisions. An RMON probe inside a repeater reports 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.

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