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NOTE: The per ip-com-port statistics will not add up perfectly to the director-level statistics category. This is because of
a very small amount (less than a MB/s typically) of IP port traffic sent over the director's management port which is not
tracked in this chart, but is tracked on the director level UDT category.
Changing the view
Use the following appropriate selection criteria to filter the data:.
● Director — Displays data for all directors or a specific director in the cluster.
● Port — Displays data for all ports or for a specific port.
● Bytes — Displays the data in bytes.
● Packets —- Displays the data in packets.
● Sent — Displays only the data sent over this WAN port.
● Received — Displays only the data received over this WAN port.
Viewing detailed data for a specific point in time
Place the mouse pointer on any point along the performance chart to display a popup box that shows detailed information about
the port performance.
Viewing the WAN Port Performance chart
1. From the GUI main menu, click Performance.
2. In the Performance Dashboard, click +Add Content.
3. Click the WAN Port Performance chart icon.
WAN Latency chart
The WAN Latency chart provides a time-based view of the WAN Latency. The categories avg-lat/min-lat/max-lat each report
values observed in the last 5 seconds or less. You can view, delete.
● Average Latency reflects the quality of service over a WAN COM port, and not just the WAN link. Factors influencing this
are the wire latency, COM latency increases because of potential COM queue build-up, re-transmitted packets due to packet
drops on the wire, or connection drops. Re-transmitted packets or connection drops can increase the maximum and average
latency values. These values normalize once the packet drops are no longer occurring.
● Minimum Latency is the best indication of underlying true wire round-trip-time (RTT) latency. It is best to rely upon average
latency as a true feel for the inter-cluster latency.
NOTE:
The chart displays data only for the directors in the cluster to which you are currently connected. To simultaneously
view WAN Latency Delta for another cluster, open a second browser session and connect to the second cluster.
Guidelines
● Know your expected inter-cluster round-trip time. This value should be similar to minimum latency, however, keep in mind
that COM queuing effects or potential inter-cluster bandwidth saturation can result in average latency being higher than the
minimum.
● It is not unusual for some observed maximum latencies to exceed the maximum supported round-trip-time values as defined
by metro node product specifications (Metro <5 msec). So long as the averages are below these defined limits, the system is
alright. However, watch for consistently high maximum values which may be an indication of WAN health issues.
● For Metro-Fibre Channel:
○ If Fibre Channel switches are used over dark fibre or DWDM WAN equipment, ensure that the WAN facing Fibre Channel
ports have sufficient buffer credits allocated to the ports. A lack of buffer credits results in higher than expected WAN
round-trip times, negatively affecting metro node's ability to communicate and send read or write requests between
clusters.
● For Brocade switches:
○ An extended fabric license is required for each edge switch, and the WAN facing ports must be set to LS or LD mode.
See the command portcfglongdistance.
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Monitoring the system