METRODATA NetTESTER FAMILY USER MANUAL
76-02-107 Rev.A
Page 41 of 133
9 SERVICE LEVEL AGREEMENTS (SLAS)
The unit uses the concept of a Service Level Agreement (SLA) as proposed by MEF
[6] This defines the service supplied to the customer by the provider in terms of a list
of measurable parameters with minimum acceptable values for each.
9.1 SLA Parameters
9.1.1 Bandwidth Parameters
CIR
Committed
Information Rate
The basic speed of the service, in bits per
second. Traffic that does not exceed this rate
and the CBS (see below) must be passed
and comply with the performance parameters
(see below).
CBS
Committed Burst Size Traffic is allowed to burst (exceed the CIR)
for short periods. The CBS specifies the
amount of data (in bytes) that a burst may
temporarily 'borrow' from the CIR.
EIR
Excess Information
Rate
The EIR specifies additional bandwidth (up to
a total of CIR + EIR) that may be available at
the provider's discretion. Note that traffic
using this excess bandwidth is not required
to comply with the performance parameters
(see below).
EBS
Excess Burst Size
EBS is the excess equivalent of CBS,
increasing the possible burst size to CBS +
EBS. As with EIR, EBS is at the discretion of
the provider, and traffic using this facility is
not required to comply with the performance
parameters.
9.1.2 Bandwidth Qualifying Parameters
In order for the bandwidth parameters to be meaningful, it must be defined exactly
which parts of the data passing over the service count as 'information'.
Bandwidth Type
There are 3 basic 'bandwidth types', as
illustrated below:
1. Information Rate. The data comprising the
Layer 2 packet (starting with the DA and
ending with the FCS) counts towards the
customer's bandwidth usage.
2. L1 Rate. As above, but the packet
preamble (8 bytes) is also included.
