9-30
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 9 Ethernet Operation
Spanning Tree (IEEE 802.1D)
9.6.5.2 Line Utilization Window
The Line Utilization window shows the percentage of line, or port, bandwidth used and the percentage
used in the past. Display the CTC card view and click the Performance and Utilization tabs to display
the window. From the Interval menu, choose a time segment interval. Valid intervals are 1 minute, 15
minutes, 1 hour, and 1 day. Press Refresh to update the data.
9.6.5.3 Utilization Formula
The utilization screen numbers may differ from the numbers encountered on an Ethernet test set. The
line utilization numbers express the average of ingress and egress traffic as a percentage of the total
capacity. Line utilization is calculated with the following formula: (In OutOctets)*8
bits/octets/100/ intervals*(maxRate*2). Intervals are defined in seconds. maxRate is defined by raw
bits/second in one direction for the circuit. maxRate is multiplied by 2 in the denominator to get the raw
bit rate in both directions.
This formula does not take into account the HDLC headers, SONET header, and inter-frame gap. This
means that the line utilization numbers do not reach 100 percent. It also means that smaller packet sizes
result in lower utilization figures.
Note
Line utilization numbers express the average of ingress and egress traffic as a percentage of capacity.
9.6.5.4 History Window
The Ethernet History window lists past Ethernet statistics. At the CTC card view, click the Performance
tab and History subtab to view the window. Choose the appropriate port from the Line menu and the
appropriate interval from the Interval menu. Press Refresh to update the data.
9.6.6 Ethernet Maintenance Screen
Display an Ethernet card in CTC card view and choose the Maintenance tab to display MAC address and
bandwidth information.
9.6.6.1 MAC Table
A MAC address is a hardware address that physically identifies a network device. The ONS 15327 MAC
table, also known as the MAC forwarding table, allows you to see all of the MAC addresses attached to
the enabled ports of an Ethernet card or an Ethernet Group. This includes the MAC address of the
Table 9-8
maxRate for STS Circuits
Circuit
maxRate
STS-1
51840000 bps
STS-3c
155000000 bps
STS-6c
311000000 bps
STS-12c
622000000 bps
Summary of Contents for ONS 15327
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Page 30: ...Figures xxviii Cisco ONS 15327 User Documentation June 2002 ...
Page 44: ...Procedures xlii Cisco ONS 15454 Installation and Operations Guide R3 2 June 2002 ...
Page 540: ...Glossary GL 16 Cisco ONS 15327 User Documentation R3 3 June 2002 ...