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FiberGateway User Manual

General Specifications

Figure 13: Wavelength planning

In  order  to  accomplish  to  that  plan,  the  upstream  wavelength  for  GPON  must  be  restricted  to  ONU
(ONT)  equipment  based  on  the  ordinary  DFB  lasers,  while  the  XGPON  downstream  signal  range  is
defined from 1575 nm to 1580 nm and the XGPON upstream signal from 1260 nm to 1280 nm. For the
coexistence of XGPON and GPON over the same fiber, the CO requires a WDM filter that combines
the  downstream  signal  (1490  nm,  1555  nm  and  1577  nm),  isolating  the  1310  nm  and  1270  nm
upstream signal, with the video signal. Also the wavelength of 1650 nm, used for fiber monitoring, has
to be handled.

In addition, ONT devices require the use of a triplexer type transceiver that include an integrated filter
or a discrete WDM filter to distinguish the different signals that may be present on the fiber. The
current networks, equipped with ONT in accordance with the current ITU-T Rec. G984.5, will be easily
updated to XGPON.

Class B+ optical budget are the nominal requirement for coexistence of GPON and XGPON over the
same optical fiber. Taking this requirement into account, the fiber network architecture will not limit the
future of the service provider business since GPON architectures, respecting B+ class of the GPON,
are easily updated by placing newest terminal equipments, namely XOLT and XONT, and by replacing
the current WDM filter by the new one in order to handle the new XGPON signals.

XGPON must support/emulate all GPON legacy services in case of total migration.

Like  GPON,  XGPON  is  required  to  support  triple  play  services  (data,  voice  and  video),  as  well  as
mobile  backhauling  (accurate  frequency/phase/time  synchronization)  application  through  its  high
quality  of service and  high  bit rate feature capabilities. Access to Ethernet services such as point-to-
point,  multipoint-to-multipoint  and  rooted-multipoint  Ethernet  Virtual  Connection  services  should  be
provided. Finally, as a global requirement, XG-PON needs to support IPv6.

3.6

GPON/Ethernet characteristics

GPON/Ethernet characteristics supported, both functional level and GTC-OMCI configuration,
corresponds with the general mandatory characteristics defined in ITU-T G.984.3, G.984.4 and G.988
Recommendation:

•

PON interface: downstream operating rate 2.488 Gbits/s, upstream operating rate 1.244
Gbits/s;

•

32 T-CONT and 256 simultaneous GEM ports;

•

1:64 SR is granted once optical power transmission from the OLT side is up from -27/30dBm;

•

Unmarked or marked bandwidth management;

•

Upstream and downstream FEC;

•

Downstream AES encryption;

•

Ethernet flow control in client´s port: 802.3x and 802.3ab;

•

Ability to classify and modify VLAN labels (single or double labeling);

•

Ability to support multiple VLAN tags per service (Internet, IPTV, VoIP, ACS, etc) from
Residencial Gateway. And ability to translate those VLAN to one specific service VLAN on