[Comtec Announce] [Core Network] EMERGENCY Maintenance windows 6-8th July 2018

[David Croft]

Please be advised of the following maintenance windows scheduled on
our core network:

Start date: Friday, 6th July 2018
Start time: 18:00 BST (UTC+0100)
End time: 04:00 BST (UTC+0100) Saturday

Start date: Saturday, 7th July 2018
Start time: 14:00 BST (UTC+0100)
End time: 04:00 BST (UTC+0100) Sunday

Start date: Sunday, 8th July 2018
Start time: 14:00 BST (UTC+0100)
End time: 04:00 BST (UTC+0100) Monday

Purpose:

We will be replacing core network devices to increase capacity and
prevent a recurrence of the outage suffered on 22nd May.

Services affected:

All

Impact:

LOW - Prior to 20:00 BST on each date
No works will take place that are known to have a possibility of
causing any service degradation, however the network is "at-risk" due
to preparatory work taking place in core network PoPs.

MEDIUM - After 20:00 BST on each date
No works that will take place that are known to have any possibility
of causing a total network outage, however works will be carried out
that will cause a reduction of resilience or the removal of a single
PoP from service.

HIGH - After 23:59 BST on each date
Works that have any possibility of triggering the cascading failure
will be reserved to take place after midnight.

Due to the nature of the instability suffered on 22nd May the
maintenance has been carefully developed to categorise works according
to both their expected (normal) risk and potential (due to the current
situation) risk and allocate them to the maintenance windows as
detailed above. This has been developed conservatively due to the
unexpected cascading nature of the previous failure.

Prior to 20:00 BST on each date, it is anticipated that no customer
suffers loss or degradation of service.

After 20:00 BST it is anticipated that single-homed customers will
experience loss of service, however customers with resilience options
will fail over to alternate paths.

After 23:59 BST it is anticipated that all customers will suffer loss
of service.

In all cases we will endeavour to keep periods of disruption to a minimum.

Please note: These maintenance windows are being declared as EMERGENCY
without the normal notice period due to the need to perform these
works urgently in order to prevent a recurrence of the outage of 22nd
May.

The immediate goal of this work is to stabilise the network to prevent
further a network outage. The second, non-essential part of the
upgrades will take place in August.

Regards,

David Croft

-- 
David Croft
Lead Engineer

Comtec Enterprises Ltd
Comtec House
46a Albert Road North
Reigate Industrial Estate
Reigate
Surrey RH2 9EL

Tel: 0845 899 1400
Fax: 0845 899 1401
www.comtec.com

For urgent operational issues please always contact noc at comtec.com
or 0845 899 1423 and not any named individual.