10G GPON最新标准

1、international telecommunication union study group 15 td 128 (plen/15) telecommunication standardization sector study period 2009-2012 english only original: english question(s):2/15geneva, 28 september - 09 october 2009 temporary document source:editors, g.xgpon987.1 title:draft new recommendation g

2、.987.1 10 gigabit-capable passive optical network (xg-pon): general requirements (for consent) this document contains version 0.6 of draft new recommendation g.987.1. note that living list for draft g.987.1 is submitted as a companion document. versionrevision pointsdate initialthe first draft skele

3、ton submitted in itu q.2/15 may 12, 2009 0.1skeleton grooming 30 users of this recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the recommendations and other references listed below. a list of the currently valid itu-t recommendations is r

4、egularly published. the reference to a document within this recommendation does not give it, as a stand-alone document, the status of a recommendation 1itu-t recommendation g.652 (2005), characteristics of a single-mode optical fibre 35cable. 2itu-t recommendation g.902 (1995), framework recommendat

5、ion on functional access networks (an) architecture and functions, access types, management and service node aspects. 3itu-t recommendation g.982 (1996), optical access networks to support services up to 40the isdn primary rate or equivalent bit rates. 4itu-t recommendation g.983.1 (2005), broadband

6、 optical access systems based on passive optical networks (pon). 5itu-t recommendation g.983.2 (2005), ont management and control interface specification for b-pon. 5 6itu-t recommendation g.983.3 (2001), a broadband optical access system with increased service capability by wavelength allocation. 7

7、itu-t recommendation g.984.1 (2008), gigabit-capable passive optical networks (gpon):general characteristics. 8itu-t recommendation g.984.2 (2008), gigabit-capable passive optical networks 10(gpon): physical media dependent (pmd) layer specifications. 9itu-t recommendation g.984.3 (2008), gigabit-ca

8、pable passive optical networks (gpon): transmission convergence layer specification. 10itu-t recommendation g.984.4 (2008), gigabit-capable passive optical networks (gpon): ont management and control interface specification. 15 11itu-t recommendation g.984.5 (2007), gigabit-capable passive optical n

9、etworks (gpon): enhancement band for gigabit-capable passive optical networks. 12itu-t recommendation i.112 (1993), vocabulary of terms for isdns. 13itu-t recommendation g.808.1 (2006), generic protection switching linear trail and subnetwork protection. 20 14itu-t recommendation g.984.6 (2008), gig

10、abit-capable passive optical networks (gpon): gpon optical reach extension (g.984.re). 15itu-t recommendation y.2201 (2007), ngn release 1 requirements 16 itu-t recommendation g.810 (1996), definitions and terminology for synchronization networks 25 17 itu-t recommendation g.813 (2003), timing chara

11、cteristics of sdh equipment slave clocks (sec) 18 itu-t recommendation g.703 (2008), physical/electrical characteristics of hierarchical digital interfaces 19 itu-t recommendation g.8261 (2008), timing and synchronization aspects in packet 30networks 20 itu-t recommendation g.8262 (2008), timing cha

12、racteristics of synchronous ethernet equipment slave clock (eec) 21 itu-t series g supplement45 (2009), means and impact of gpon power saving. white paper 35 22itu-t recommendation g.987 (20xx), g.xgpon definitions, abbreviations and acronyms 23 itu-t recommendation g.987.2 (20xx),10-gigabit-capable

13、 passive optical networks (xg-pon): physical media dependent (pmd) layer specification 24itu-t recommendation y.2001 (12/2004), general overview of ngn. 25itu-t recommendation j.186 (july/2003), transmission equipment for multi-channel 40television signals over optical access networks by sub-carrier

14、 multiplexing (scm). 3definitions see itu-t rec. g.987 22, clause 3. 4abbreviations and acronyms 5 see itu-t rec. g.987 22, clause 4. 5architecture of the optical access network 5.1network architecture the optical section of a local access network system can be either active or passive and its archi

15、tecture can be either point-to-point or point-to-multipoint. figure 1shows the considered 10 architectures, which range from fibre to the home (ftth), fibre to the cell sites (fttcell), fibre to the building/curb (fttb/c), to the fibre to the cabinet (fttcab), etc. the optical distribution network (

16、odn) is common to all architectures shown in figure 1; hence the commonality of this system has the potential to generate large worldwide volumes. 15 figure 1 - network architecture the differences among these fttx options are mainly due to the different services supported and the different location

17、s of the onus rather than the odn itself, so they can be treated as one in this recommendation. it must be noted that a single olt optical interface might accommodate a 20 combination of several scenarios described hereafter. xg-pon should extend the g.984.6 reach extenders capability, inherited fro

18、m the g.984 recommendations series, to produce extra optical budget to achieve longer distances and/or additional passive split. 5.1.1fttb scenario 5 the fttb scenario is divided into two scenarios, one for multi-dwelling units (mdu) and the other for businesses or mixed environments (mtu). each sce

19、nario has the following service categories: 5.1.1.1 fttb for mdu served residential users asymmetric broadband services (e.g., iptv, digital broadcast services, vod, file download, etc.). 10 symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance learning, telemedicine

20、, online-game, etc.). pots - the access network must be able to provide, in a flexible way, narrow-band telephone services with appropriate using either emulation (complete replication of a legacy service) or simulation (providing a service that is almost the same as the legacy service). 155.1.1.2 f

21、ttb for mtu served business users symmetric broadband services (e.g. group software, content broadcast, e-mail, file exchange, etc.). pots - the access network must be able to provide, in a flexible way, narrow-band telephone services using either emulation (complete replication of a legacy service)

22、 or 20simulation (providing a service that is almost the same as the legacy service). private line. the access network must be able to provide, in a flexible way, private line services at several rates. 5.1.2fttc and fttcab scenario within this scenario, the following service categories have been co

23、nsidered: 25 asymmetric broadband services (e.g., iptv, digital broadcast services, vod, file download, online-game, etc.). symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance learning, telemedicine, etc.). pots - the access network must be able to provide, in a fl

24、exible way, narrow-band 30telephone services using either emulation (complete replication of a legacy service) or simulation (providing a service that is almost the same as the legacy service). xdsl backhaul. 5.1.3ftth scenario within this scenario, the following service categories have been conside

25、red: 35 asymmetric broadband services (e.g., iptv, digital broadcast services, vod, file download, etc.). symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance learning, telemedicine, online-game, etc.). pots - the access network must be able to provide, in a flexibl

26、e way, narrow-band telephone services using either emulation (complete replication of a legacy service) or 5simulation (providing a service that is almost the same as the legacy service). 5.1.4ftto scenario ftto addresses business onu dedicated to a small business customer. within this scenario, the

27、 following service categories have been considered: symmetric broadband services (e.g., group software, content broadcast, e-mail, file 10exchange, etc.). pots - the access network must be able to provide, in a flexible way, narrow-band telephone services using either emulation (complete replication

28、 of a legacy service) or simulation (providing a service that is almost the same as the legacy service). private line. the access network must be able to provide, in a flexible way, private line 15services at several rates. 5.1.5fttcell wireless scenario within this scenario, the onu will be called

29、cbu and will have to offer connectivity to wireless base stations: 20-symmetric tdm services (e.g. 2g cell site backhaul) -symmetric/asymmetric packet based broadband services (e.g. 3g/4g cell site backhaul) -hot spots within this scenario, the onu will be called cbu and will have to offer connectiv

30、ity to wireless 25 base stations: figure 2 represents exemplary scenarios of xg-pon applications. - 5- figure 2 - a summary of some xg-pon scenarios 5.1.6environment conditions in outdoor scenarios for supporting the wide range of scenarios and applications, optical parameters for the olt and the 10

31、 onu should be determined to allow an outdoor operation. 5.2 reference configuration a high level and simple reference configuration of xg-pon is depicted in figure 3, which shows very similar high level reference configuration as g.983 and g.984 series. service node functions onu onu odn olt af r/s

32、 s/r sni (v) reference point uni (t) reference point (a) reference point network side user side access network management functions figure 3 - high level reference configuration of xg-pon figure 4 - reference access network architecture figure 4 depicts generic optical access network (oan) reference

33、 architecture that applies to the xg-pon. it includes an olt, onus and an optical distribution network (odn) between them. 5 as shown in figure 4, an xg-pon odn can consist of a single pon or a group of pons interconnected via reach extender 22. further, reference architecture of xg-pon system showi

34、ng how xg-pon and g-pon can co-exist on the same odn is detailed in figure 5. onu (gpon) logic tx wbfrx wdm -n olt (gpon) wdm-l rx tx logic olt (video) onu (gpon + video) logic tx wbfrx wdm -n v-rxwbf-v onu (ngpon1) splitter ifgpon ifgpon, ifvideo ifngpon1 ifgpon ifvideo wdm1r wdm2 additional split

35、tbd olt (ngpon1) ifngpon1 additional split tbd optional legacy g-pon unchanged multi-stage splitter available 2-by-n splitter available instead of wdm1 (see figure 3 of itu-t g.984.5) figure 5 - reference optical configuration for xg-pon 5functions of wdfs and wdms that enables the g-pon and xg-pon

36、co-existence as shown in figure 5are listed follows: wbf wavelength blocking filter for blocking the interference signals to rx. wbf-v wavelength blocking filter for blocking the interference signals to v-rx. wdm-n wdm filter in gpon onu to combine/isolate the wavelengths of g 10pon upstream and dow

37、nstream. wdm-n wdm filter in gpon onu to combine/isolate the wavelengths of g pon upstream and downstream and isolate the video signal(s). wdm-lwdm filter in gpon olt to combine/isolate the wavelengths of g pon upstream and downstream. 15wdm1rwdm filter which is located in the central office to comb

38、ine/isolate the wavelengths of gpon and xgpon/video signals. wdm2optional wdm filter which may be located in the central office to combine/isolate the wavelengths of xgpon and video signals. 205.2.1user network interface (uni) and service node interface (sni) as depicted in figure 3, onu provides un

39、i towards end users, while the olt provides the sni interface towards the core network. the types of uni/sni interfaces depend on the services that the service provider offers. see itu-t rec. g.902 2. the examples of uni are described in appendix i clause i.1.2. 25the examples of sni are described i

40、n appendix i clause i.1.3 5.2.2interface at the reference points s/r and r/s the interface at reference points s/r and r/s at olt and onu optical port is defined as ifxg-pon. this is a pon-specific interface that supports all the protocol elements necessary to allow 30 transmission between olt and o

41、nus. 6migration scenarios gigabit pons such as gpon (itut g.984 series) and 1g-epon (ieee 802.3-2008) have been standardized and are now being deployed worldwide. with the ever increasing bandwidth demand 5 from consumer and business applications, the most general requirement for a nextgeneration po

42、n (ngpon) is to provide higher bandwidth than gigabit pon. in addition, given the major investments spent on time and money on deploying gigabit pon mainly in the fibre infrastructure, ng-pon must be able to protect the investment of the legacy gigabit pons by ensuring a subscriber seamless and smoo

43、th migration capability from gigabit pon to ngpon. co-existence 10 between xgpon and g-pon, which is addressed by this specification, is enabled through the wavelength band plan enhancements specified in recommendation g.984.5, which also provides optional overlay capability of broadcast tv on a sep

44、arate wavelength. co-existence with other legacy pon systems is for further study and will not be covered in this version of the specification. there are several migration scenarios to meet different service providers needs. these reflect 15 recognition that differing service introduction strategies

45、 might affect requirements for the ng-pon specifications. this section describes two likely migration scenarios: pon brown field migration scenario: pon brown field scenario in this specification refers to the deployment scenario where a pon system has already been deployed and network operators dec

46、ide to leverage this existing fibre 20 infrastructure to offer higher bandwidth carrier services, using xg-pon. some subscribers on an existing gigabit pon system might require an upgrade to such higher speed tier service and the network operator may therefore choose to move over these subscribers t

47、o the xg-pon system, while other subscribers remain on the gigabit pons. at certain point some network operators may eventually perform a forced migration from gigabit pon to xg-pon when the number of 25 gigabit pon subscribers becomes low. it is likely that both gigabit pons and xg-pons will contin

48、ue to co-exist for a relative long time in this scenario. in a similar, but slightly different migration scenario, a network operator might want to replace an existing gigabit pon with a xg- pon completely. in this case, it would still make sense to run both gigabit pon and xg-pon at the same time a

49、nd update customers one at a time. but, the upgrade window is rather much shorter. 30 general requirements for this scenario are as follows: - co-existence between gigabit pon and xg-pon on the same fibre must be supported for the case that the fibre resource is not necessarily abundant. - service i

50、nterruption for the non-upgrade subscribers should be minimized. - xg pon must support/emulate all gpon legacy services in the case of full migration. 35 pon green field migration scenario: renovating access network to fttx infrastructure is the biggest investment of service providers and may take l

51、ong time. when xg-pon technology becomes mature, service providers might be interested in using xg-pon to replace copper based infrastructure or to deploy in a brand new 40 development area for the benefit of higher bandwidth and/or higher splitting ratio. an area where gigabit pon had not been depl

52、oyed before is referred to as “pon green field”. this scenario may help service providers achieving better economics while supporting the same or better bandwidth offer per user as gigabit pon. in this scenario, the requirement of co-existence with gigabit pons is not necessary. 456.1migration from

53、legacy pon to xg-pon to assure this smooth migration capability, overlay through wdm technology in compliancy to optical wavelength allocation described in g.984.5 must be implemented in all onu. it will of course remain the choice of the operator to use this capability or rather run a full pon acti

54、ve 5 devices replacement from day1 of an upgrade process. in transition period, to get simultaneous g-pon and xg-pon working, a wdm1 combiner/splitter is installed in the network as illustrated in figure 6. 10 g-pon olt onu onu onu onu onu onu onu onu wdm1r e.g. g-pon with 32-way split gives each cu

55、stomer sustained bandwidth 80/40 mbit/s xg-pon1 with same split gives each customer sustained bandwidth 320/80 mbit/s 1490nm/1310 nm gpon key xg-pon xg-pon olt onu gpon olt onu xg-pon olt onu gpon olt onu g-pon olt figure 6- co-existence of g- pon and xg-pon required wdm1r characteristics and perfor

56、mances can be found in g.984.5 am1. 156.2migration from xg-pon1 to xg-pon2 the need of co-existence between xg-pon1 and xg-pon2 still needs further study and therefore will not be addressed in this version, but rather will be addressed in the future revision, regardless the need of the co-existence

57、requirement, it is desirable to support a common tc layer for xg pon1 and xgpon2 derived from g-pons tc with necessary enhancements. 206.3overlay of xg-pon or hybrid xg-pon it is possible to overlay multiple xgpons on the same odn to create even higher capacity using wdm. in such extensions, spectru

58、m allocation is critical to make this overlay approach work. the requirement for overlaying xg-pon or hybrid xg-pon is for further study in the future revision. 256.4re architecture options this section is focusing on mid-span architectures, since single end solutions such as described in g.984.6 wi

59、ll be part of each dedicated technology options and as such will be treated as olt implementation options. 5 in the xg-pon world, two main architectures involving reach extenders are required that are described in figure 7: one for deployments in which network consolidation will take place when migr

60、ating from g-pon to xg-pon 10the other for deployments in which re have already been deployed for the g-pon systems. in which case two situations will occur depending on the early re technology deployed: oeither the re had from the start the capability to cover g-pon and xg-pon requirements oor the