6. Circuits Greater Than 70 Percent Of Max Capacity

6.1. Introduction

The Circuits Greater Than 70% Of Max Capacity dashboard shows circuits where usage has peaked above 70 percent of maximum capacity, where that has happened more than once in the last 7 days, and ending at midnight on the current day.

The purpose of the dashboard is to allow Jisc staff to identify customer connections that are running hot, in order to help with capacity planning, and to also help determine when Account Managers should be approaching customers to discuss upgrading their connection.

6.2. Accessing the dashboard

The dashboard is accessible to all Jisc staff with a Netsight3 login, and can be accessed via an option on the Explore menu:

6.3. About the data driving the dashboard

The data powering the dashboard is not dynamic or real time. It is static, and refreshed each day, so will be up to 24 hours out of date.

This is done because the report can take a number of minutes to build, and therefore has to be compiled in batch mode each morning.

The data has also been down sampled, and is based on the maximum value in Mbps for each hour. This is done to limit the size of the data set. An event is registered if the maximum value in each hour exceeds 70% of maximum capacity rate-limited on that circuit.

6.4. How the maximum capacity of each circuit is measured

Most customer connections are at least 1Gbps, but many are rate-limited down to 100Mbps. It is possible to determine link speed via SNMP, but this would report 1Gbps not 100Mbps in the example above. In order to determine the rate-limited speed we must therefore refer to the interface descriptions, and try and derive the link speed by parsing it out of the description string. This is not always accurate so sometimes circuits displayed in the dashboard will have the wrong link speed, and report traffic rates in excess of 100% of maximum.

In the example below the circuit is labelled as FE/TX which describes a 100Mbps connection. However, the circuit is reporting at 528% of that capacity. This is clearly a 1Gbps connection running at about half capacity. Likely it was upgraded but the interface description hasn't been amended to reflect that.

(See the Wiki for more information about circuit descriptions.)

6.5. Circuits peaking above 90% capacity

There are two lists of circuits on the dashboard, sorted into those connections peaking above 90% (marked red), and those above 70% (marked orange).

The circuits above 90% capacity are shown at the top of the page as cards.

The header part of the card is marked in red and displays the circuit description (alias) at the top. This matches how the circuit is described in the SNMP response.

6.5.1. Circuit cards linked to Netsight3 reporting paths

The interface description is used to label each card because not every circuit which may be peaking will be described with a reporting path in Netsight3. Where there is a corresponding reporting path however, this is linked to from the header, and moving your mouse pointer over the interface description will show a link where that is the case.

Selecting on the link will open the reporting path information in a new tab.

6.5.2. The card body display

A number of pieces of information are displayed on each circuit card, in the white card body area. From top to bottom, first is the maximum percentage of capacity achieved over the reporting period of the previous week. In addition, we also have displayed whether that peak was on traffic incoming to Janet, or outgoing from Janet to the customer e.g. Peaked at 93.09% of 100M (out).

Immediately below, we have the number of events in the last week where the 70%-of-capacity threshold was breached. Note that an event is defined as being where the maximum capacity achieved in any 1 hour is greater than 70% of the maximum capacity allowed on the circuit e.g. 3 events in the last 7 days.

6.5.3. The Graph and Percentile Buttons

Each card body contains two buttons. Selecting the first opens a graph display for that circuit in a new tab.

N.B. It is strongly recommended that you examine the graphs for each circuit, as this will give you a much fuller picture of activity on the circuit than is available from the dashboard.

The graphs show the traffic in and out for the circuit, at a 5 minute resolution, for the past week (as opposed to the 1 hour resolution of the dashboard). Besides the Traffic In and Traffic Out traces, the graphs include lines marking 70% and 90% of maximum, in orange and blue respectively. As with all other Netsight3 graphs, you can adjust the time range, and look further back in time if you wish to.

Note that once you select the Graph button on a card, the card header changes colour to purple. This is to indicate which circuits have already been checked during this session.

In addition to the Graph button a Percentiles button is also displayed. Selecting this button will show a pop-up layer with percentiles and traffic volume information for the last week.

6.5.4. Marking circuits as already actioned

It is possible to mark circuits that have previously been checked, and where the details have already been passed on to the relevant Account Manager for further investigation with the customer. You can do this so you don't keep checking the same circuits week after week that have already been dealt with.

The cards for these circuits are displayed with a grey header, and the checkbox is checked in the bottom right-hand corner of the card.

This persists for that circuit even when the dashboard data is refreshed each morning.

To mark a card as actioned if it isn't already, you just need to click the checkbox in the bottom right-hand corner. Note that it may take a few seconds for the page to refresh. There is no need to click more than once.

6.5.5. Circuits with very large percentages above 100%

Sometimes circuits will be included which have very large percentages over 100. In the example above, the circuit appears to have peaked at 175616.56% of maximum capacity. This is clearly impossible. This is instead caused by a spike in the data as a result of an SNMP counter reset event, and can be safely ignored.

6.6. Circuits peaking above 70% capacity

If you scroll down you will see a list of cards with orange headers for circuits that have peaked above 70% of maximum capacity, but which did not breach the 90% threshold. Other than having orange headers, the features of these cards are identical to those in the 90% category.