8/13/2019 Ethernet Over SDH Verses Ether Point to Point
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Ethernet Over SDH Verses Ether Point to Point
Though both products product the same result, i.e. an Ethernet
circuit from point A to point B,the way the circuits are
constructed and the technology utilised allows for different
resilienceand monitoring capabilities.
The Ether Point to Point product offered by NTL is comparable to
BT LES and is a directfibre lin from point A to point B. This fibre
is patch across !arious hub sites that are locatedbetween the two
sites, but no acti!e it is utilised at these locations. The only
acti!e it arethe two bo"es placed at either ends of the circuit#.
$ne of these bo"es has a BEL lineattached that allows NTL to
monitor the circuits. This product allows for a cheap fast
ser!ice,but there is no resilience at all. Loss of ser!ice can
occur at any point on the circuit, from the%PE at the customer end,
to a cable brea at any point on the circuit.
The Ether o!er S&' product utilises different technologies
that allow for a much moreresilient ser!ice. To the customer, they
are presented with an Ethernet connection from the%PE at the
customer premises. This bo" has a direct fibre connection to the
nearest NTL hubsite. At this hub site, the signal is con!erted to
the S&' framing standard, and is then sent
around our S&' networ. As our S&' networ is made up of
rings, the signal is split, anddifferent parts are sent in
different directions, until they meet at the hub site nearest to
pointB. At this hub site, the pacets are reassembled into Ethernet
presentation and sent to thecustomers site. The main benefit of
this ser!ice is that greater distances can be reached, anda fault
of the S&' networ will not mean a loss of ser!ice as if a brea
occurs, the signal willloop around in the other direction. Below is
an e"tract from one of the technical clarificationdocuments from
the tendering process that e"plains in detail the S&'
Technology.
Ethernet Over SDH
Ethernet o!er S&' is a natural de!elopment from Transmission
suppliers to meet the currentdemand for wire speed bandwidths o!er
e"isting legacy S&' networs. (n essence supplying)ncontended
*anaged Pri!ate Ethernet Leased Lines mapped across an S&'
bacbone.
The ad!antages of using S&' are end+to+end networ
management, full diagnosticcapability, fault monitoring and
statistical performance reporting.
The presentation of the Ethernet circuit is #BASE+T-#BASE+T
configurable interfaces,which are auto sensing / auto negotiating.
There are 0 !ariants of Ethernet $!er S&' card,which fit in to
a standard S&' mutiple"er.
$ptical
Electrical
Both cards ha!e a similar basic board configuration and
functionality with the e"ception ofthe Ethernet interfaces, with
the electrical card ha!ing 1234 interfaces and the optical
ha!ingS5P6s 7small form factor pluggable optics8. The optical card
will e"tend the circuit to thecustomers premises !ia an EPE
7Ethernet port E"tender8, which will then pro!ide an 12
34#BASE+T-#BASE+T e"tended to the customer site 7*a" 3m8. The EPE
also e"tendsthe full range S&' benefits to the customer site
including management, fault diagnostics andperformance monitoring.
The EPE is managed within a dedicated out of band
opticalcommunications channel e"tended from the core
multiple"er.
The ethernet o!er S&' card is logically split in two
domains, an ethernet and an S&'domain. The ethernet domain
pro!ides the ethernet framing and lin to the physical card
portwhilst the S&' domain treats the bachaul circuit as
indi!idual 9%+#0, 9%+: or 9%+36s.
The Ethernet frame is logically mapped into S&' !irtual
containers using ;5P 7;eneric5raming Procedure8 which forms a
!irtually concatenated group 79%;8 of n " 9%+#0, 9%+: or
