SK Broadband & SK Telecom (SK) introduced various gigabit Internet access network solutions at the World IT Show 2014 held in Busan on October 20th. SK noted that the new solutions will be able to provide a bidirectional Internet speed of 1 Gbps per user. The company has been offering Internet services including LAN, FTTH, HFC and XDSL to its 4.7 million subscribers.
At the show, the company demonstrated the technology and equipment that can accelerate speeds of the same services ten times faster, from the current 100 Mbps to 1 Gbps.
Below, we will share with you what we have discovered at the show about the SK's gigabit Internet access network solutions. SK's gigabit Internet access network consists of two different segments: segment with optical fiber cabling (from SK's CO to ONT subscriber, and from SK's CO to ONU) and segment inside apartment buildings with non-optical fiber cabling (from MDF to households). The gigabit Internet access networks for different segments are:
Segment with Optical Fiber Cabling
(FTTH: from SK's CO to ONT subscribers & FTTB: from SK's CO to ONU)
At the show: SK currently offers 100 Mbps FTTH and LAN services with GPON as seen (1) in the figure below. At the show, it presented various solutions such as XG-PON (HFR), 10G-EPON (Dasan), NG-PON2 (Alcatel) solutions as its next-generation FTTH access network solutions. It also proposed a new concept of migrating the current GPON to the next-generation PON network (see (3) in the figure below). Particularly, it demonstrated a solution for 10G-EPON by configuring a demo network using equipment from Dasan.
(3) in the figure below illustrates SK's concept of migrating GPON access network. New OLTs (specific technologies to be deployed are not determined yet, but would be 10G-EPON, XG-PON or NG-PON2) will be added in SK's CO. Also, new ONUs and ONTs will be introduced in apartment buildings and single homes, respectively.
As installing extra optical fiber cables for the new PON network between COs and ONUs (or ONTs) is almost impossible, the main idea of the migration concept is to introduce WDM as seen in below so that fiber infra can be shared between legacy GPON network and new PON network.
SK's plan for gigabit Internet service (taking advantage of existing GPON network): SK said it aims to provide 1 Gbps service through the current GPON (i.e. by just switching a setting of the current GPON OLT and ONT to 1 Gbps) at the initial stage of the service. SK's current networks are GPON, and thus DL speed at PON port is 2.5 Gbps, which is twice that of EPON. So, the company is now considering using the current GPON at the initial stage (see (2) in the figure above), and then introducing XG-PON or 10G EPON later when giga Internet subscription grows in the near future, or even direct-jumping to NG-PON2. And the final decision on this will be made later.
The next-generation PON equipment displayed at the show:
XG-PON: XG-PON is an ITU-T standard technology that supports 10G/2.5G in DL/UL. At the show, HFR's solution (XG-PON OLT, ONU, ONT) was displayed.
10GE-PON: 10G EPON is an IEEE standard technology that supports 10G/10G and 10G/1G in DL/UL. At the show, Dasan's solution (10G EPON OLT, ONU, ONT) was presented, demonstrating a demo network of GPON+10G-EPON.
NG-PON2: NG-PON2 is an ITU-T standard technology that supports 40G/40G and 40G/10G in DL/UL. At the show, Alcatel's solution (NG-PON2 OLT, ONU) was presented.
Inside apartment building with UTP cabling
In Korea, one of the most crowded nations, large or small-scaled multi-family housings such as apartments, condominiums, and townhomes are very common. So, at the show SK introduced a variety of gigabit Internet access network solutions that it designed to meet the needs for different housing types, and new equipment (2-Pair Ethernet, Ultra Compact L2 Switch) that it developed jointly with Korean vendors (HFR, Syscable, Dasan).
2-Pair Ethernet: In accordance with the standards, Fast Ethernet offers 100 Mbps by using 2 pairs of lines inside a UTP Cat 5 cable while Gigabit Ethernet offers 1 Gbps by using all 4 pairs of lines inside a UTP Cat5e/6 cable. Different pairs of lines in different types of cables are required to support different speeds. But, SK's new 2-pair Ethernet can, with the same Cat 5 cable, offer either 500 Mbps (if using only 2 pairs of lines inside the cable) or 1 Gbps (if using all 4 pairs).
This solution allows users living in an old apartment unit with only UTP Cat5 cable to enjoy 500Mbps or 1Gbps Internet connection as well. In addition, it allows users with UTP Cat5/5e/6 cabling (using 1 pair for phone service and 2 pairs for 100 Mbps Internet service) to enjoy upgraded Internet speeds (500 Mbps) through the same 2 pairs of lines without having to install additional lines. For the demonstration of this solution at the show, SK used HFR's equipment, which has been used in SK's commercial networks since in 2013. For more information about 2-pair Ethernet, see "Korean big 3 telcos offer hassle-free and instant upgrade to Giga-class Internet without re-cabling"
Ultra-compact L2 Switch: SK displayed its newest invention, an ultra-compact giga L2 switch (S0104P by Syscable) like LG U+'s. Usually IDFs in old apartment buildings are too narrow to hold large L2 switches, and also supplying power for large L2 switches is not easy. To this kind of issue, this ultra-compact L2 switch can be a perfect solution as it can be easily placed even in a narrow no-powered IDF, delivering 1 Gbps to up to 4 units. It’s small, needs no power, and delivers giga. Couldn’t be better! Power for the switch (and of course data as well) is delivered through UTP cables via a PSE (Power Source Equipment) unit installed in MDF, e.g. S0104PI by Syscable. The company said the switch was already introduced in its commercial networks earlier this year. Although the switch is currently supporting 100 Mbps only, it should be able to provide 1 Gbps without equipment replacement once the giga Internet service is commercialized.
Ultra-compact ONU, another new invention of SK, deserves some attention too.
As seen below, for a large-scale apartment or condominium building with many households, giga ONU and ultra-compact giga L2 switch are installed in MDF and in IDF respectively, to serve a large number of households.
For a small-scale multi-family housing like townhomes, a single unit of this ultra-compact ONU with 8 subscriber ports (V2808G by Dasan) will do the job nicely.
Inside old apartment building with telephone lines (twisted pair) only
G.Fast: G.Fast is an ITU-T standard technology that can support giga-class Internet service through telephone lines. As highlighted below, this technology can offer giga-class Internet service to users living in an old apartment building with telephone lines only, by simply switching equipment (VDSL DSLAM ⇒ G.Fast ONU in the building MDF, and VDSL modem ⇒ G.Fast CPE in each unit) without the hassle of installing additional cables. For the show, equipment by Alcatel was used. But soon next year, Korean vendors plan to release products with the same purpose. G.Fast is gaining global popularity because of the fact that it allows for giga service through telephone lines as well. Like most countries in the world, SK is planning to commercialize the service in 2016.
From what we saw at the show, SK, after many years of well-planned preparation, seems to be more than ready for giga Internet service commercialization, and is expected to join KT, who first commercialized the service on October 20th, pretty soon.