ability of network connectivity. The scheduled
maintenance is not counted as outage; it will be
announced to the customer at least 48 hours in
advance, and it may be scheduled for regular
window periods (e.g. from 7 a.m. – 9 a.m. every
Tuesday and Friday). Network failure will result
in the customer’s account being credited for each
hour of down time. UUNet will notify customers
within 15 minutes in the event of network failure.
Customer care quality– UUNet will contact
the customer after detecting the unavailability
on his links via pager, phone, fax or e-mail. The
period to notify the customer of the outage is
specified in SLAs, but varies for different ser-
vices / market segments. Failing to notify the
customer in the agreed period causes the possi-
bility to realise UUNet’s crediting of the service.
Regarding installation, the time given in SLAs
varies from service to service, e.g. UUNet guar-
antees that the installation of the circuit and the
activation of the UUNet port will be completed
within 20 working days for 64 kbit/s leased line
services and 40 working days for 128 kbit/s to
2 Mbit/s services. For 8 Mbit/s services, installa-
tion and activation will be completed by the date
provided in writing by a UUNet sales manager.
Failure to do so will result in the customer
receiving a 50 % refund on the start-up charge.
The reaction pattern in case any guarantees are
broken by UUNet results in service crediting.
The customer has to initiate a remedy procedure
in the agreed period (e.g. 5 days from outage for
reporting it to the local UUNet representative,
which is a contact person stated in the SLA).
On the other hand, for some services (e.g. IP
VPN) constraints are put on the amount of traffic
the customer can inject into the network (if it
exceeds 50 % then the customer has to initiate
the request for capacity upgrade within 30 days)
[uunet2].
5.2 EPOCH Internet
Epoch Internet [epoch] is an ISP that provides
high-performance dedicated access and VPN and
web hosting/co-location services to customers in
the USA. Epoch Internet offers SLAs for its ser-
vice for dedicated access [epoch-a] and web-
hosting [epoch-w], which have basically same
structure, but are service specific for certain
parameters, and the values of parameters differ.
The SLA for web-hosting/co-location services
[epoch-sla] is an example of an SP SLA for
hosting several servers on behalf of its cus-
tomers. It is typical for these SLAs to use uptime
and the performance of servers as a gauge for
SLA satisfaction. The crucial issue for this type
of SLA is to assure that presence of multiple
users (since they host multiple customers) simul-
taneously does not affect the SLA performance
guarantees.Verification of SLAs is done by continuous
monitoring, at the time granularity of 10 min-
utes. Network outage notification and availabil-
ity is one of the guarantees included in this SLA.
To warrant network reliability, the SLA contains
a Packet Loss guarantee (monthly average
packet loss < 5 %, measured each 10 minutes,
averaged monthly) and an Internet Latency
Guarantee (monthly average < 85 ms, measured
each 10 minutes, RTT on the Epoch network,
averaged per month). In case any of the guaran-
tees are broken by Epoch, a scheme for claiming
service credits should be supplied by the cus-
tomer. If confirmed by examining monitoring
data, the customer will receive the discount. A
service credit in the SLA implies that the service
is granted for the period the service credit is
given. Epoch bases its pricing policy on the
service credit issued upon establishment and
approval of a service request. The customer will
be billed monthly and failure to comply with
Epoch’s terms and conditions will cause a
breach of the SLA. This SLA is created on the
‘one fits all’ basis and Epoch may at any time
choose to change, amend or revise its conditions
by posting it on its website. Regarding availabil-
ity the following is guaranteed for webhosting/
co-location services7):Hardware availability– 99.9 % for all the hard-
ware sited in the Epoch network;Power availability– 99.9 % for supply of AC
power to the components in case of co-location
service;Core applications availability– 99.9 % per
month for all services, but not for ROOT
service8);Data centre availability– 99.9 % from customer
to data centre for co-location customer, and only
to data centre for web-hosting customer.Backbone Network Availability Guarantee–
Epoch guarantees that the network will be avail-
able 99.9 % of the time (excluding any planned/
scheduled downtime that Epoch informed the
customer of). Any customer who has experi-
enced unavailability (UA) of links, may claim
service credits according to the following rules:- 40' ≤UA ≤4h implies service credit of 1*1/30
(one day);
7)For the dedicated access services only the backbone network availability applies.
8)For detailed description of the Epoch services visit [epoch].