16[ [ 11

Ngy nay, cng ngh thng tin ng vai tr quan trng i vi s pht trin ca hu ht ngnh ngh v lnh vc. Chnh v vy, vic m bo ngun in cho cc thit b CNTT hot ng n nh tr thnh nhu cu thit yu khng nhng i vi cc doanh nghip qui m ln, thm ch i vi cc doanh nghip va v nh. Tuy nhin, cht lng in li ti Vit Nam cha tht s m bo. Theo thng tin t Tng Cng ty in lc min Nam EVNSPCC (thng 12/2013) Cc ng dy trc chnh ni lin cc tnh, cc trm bin p trong h thng in quc gia xy dng t nhng thp nin trc xung cp v khng cn p ng tt yu cu cung cp in. Hu ht cc hng mc ca trm bin p c xung cp, hoc cng ngh c v lc hu. l mt trong s nhiu nguyn nhn lm gim cht lng ngun in cung cp, dn n tnh trng mt in, ngun in b tng p v gim p t ngt, lm gim tui th hoc thm ch gy chy n thit b. Chnh v vy, vic trang b UPS khc phc nhng s c trn l iu cn phi lm i vi tt c doanh nghip, thm ch l SOHO.

Phn loi UPSVy UPS l g? Ni n gin, UPS l mt thit b c th cung cp ngun in d phng tm thi nhm duy tr hot ng cho cc thit b s dng in khi gp s c (mt in, st gim in p, tng p...) trong mt khong thi gian nht nh. Ty theo cng sut gii hn ca UPS, ngun in d phng c th cung cp trong khong thi gian cc thit b quan trng c tt mt cch an ton v khng mt d liu; hoc trong thi gian di hn, gi ti n khi my pht in hot ng. Hin nay trn th trng c rt nhiu loi UPS, c chia lm 3 loi: Offline (hoc Standby), Line-Interactive v Online. Trong , UPS Online c xem l dng sn phm cao cp nht v ng dng cc cng ngh tin tin, bo v cc thit b trc hu ht cc s c v in. Tuy nhin, dng sn phm ny c gi thnh rt cao, v ngi dng cng khng d la chn c UPS Online ph hp vi nhu cu, cn phi c t vn chuyn su ca chuyn vin k thut hoc chuyn gia t hng. V vy, UPS Online thng c dng cho cc h thng ln v quan trng nh server,

ATM, my xt nghim y khoa, h thng iu khin Ngc li, dng UPS Offline v Line-Interactive vi th mnh l gi thnh v dy cng sut thp nn thng c cc doanh nghip SMB trang b. Tuy nhin, gia Line-Interactive v Offline, u l la chn ti u v thng minh? Mt vi tiu ch c bn c cp trong bi vit di y s gip chng ta tm ra u l sn phm ph hp.

Offline & Line-Interactiveu tin, cn phn bit s khc nhau gia Offline v Line-Interactive. UPS Offline l dng sn phm ph thng v c s dng nhiu nht trn th trng hin nay. Nguyn tc hot ng ca UPS Offline l in li u vo i qua cng tc chuyn mch trc khi cp cho thit b s dng. Lc ny, UPS ch s dng b sc np y in cho c quy. Trng hp in li khng n nh (qu cao, qu thp hoc mt in), UPS s t ng chuyn mch (thng qua Inverter), v dng ngun in t c quy cp cho thit b duy tr hot ng (Hnh 1). Mt trong nhng hn ch ca UPS Offline l ngun in cung cp cho thit b s

UPS Offline v Line-Interactive vi th mnh l gi thnh v dy cng sut thp nn thng c cc doanh nghip SMB v SOHO trang b. Tuy nhin, gia Line-Interactive v Offline, u l la chn ti u v thng minh?

17652014

Hnh 1 Hnh 2

dng khng phi l ngun in sch sng in u ra khng theo dng sine chun. Mt s thit b in t yu cu phi dng sng sine tuyt i, nu khng s nhanh h hng v gp mt vi vn nh qut chy gy ting n, nh sng n tup nhp nhy, adapter c th b chy n Ngoi ra, do s dng r-le chuyn mch nn thi gian chuyn t ngun in li sang pin mt khong 12 mili giy. Khong thi gian chuyn mch ny kh cao nn thit b hot ng gin on. Do , UPS Offline ch dng cho nhng thit b t nhy cm v in v gi tr khng cao nh mn hnh, thit b pht WiFi, modem ADSL, PC th h c (Pentium 4, Core Dual). Do UPS Offline khng c tch hp cc b t bin p, phi thng xuyn dng in t pin nn v c bn khng hiu qu trong vic gia tng tui th cho thit b cng nh chnh UPS. Trn thc t, UPS Offline ch bo v thit b in trong 3 trng hp: mt in, gim p tc thi thi hoc tng p tc thi trong khong thi gian ngn nn Offline c nh gi thp nht trong cc dng UPS. V c bn, Line Interactive ging nh UPS Offline nhng c tch hp

thm mt b t bin p AVRAutomatic Voltage Regulator. AVR l cng ngh c chc nng nh thit b bin p, gip iu chnh in p u vo ln hoc xung trc khi cho i qua thit b bo v. Chng hn, vi nhng s c gim p (di 90% in p chun) hay tng p (trn 110% in p chun) ko di, UPS Line-interactive s khng chuyn sang s dng pin, m dng b t bin p iu chnh dng in tr li mc n nh, m bo ng thng s yu cu, sau a dng in ny n cc thit b; cn trong trng hp ngun in b ngt, in p tng hoc gim vi bin ln ngoi dy in p qui nh ca UPS th UPS s chuyn sang s dng pin bo v thit b (Hnh 2). Thi gian chuyn mch t in li sang pin cn t 2~6 ms, nhanh hn nhiu so vi UPS Offline. V kh nng bo v thit b in, dng Line-Interactive vt tri hn hn so vi Offline do gii quyt c 5 s c in bao gm: mt in, gim p tc thi, tng p tc thi, gim p v tng p trong thi gian di.

B sc

Pin

Trng thi bnh thng

Mt in, gim p hoc xung t bin thin

B sc Inverter

Inverter

Ngu

n vo

Ngu

n vo

Ti u ra

Ti u ra

Pin

Ngun vo

B sc pin

ng i ca dng inTrng thi bnh thng

Khi s dng Pinang sc Pin

B t bin p

Pin

Ti u ra

Kt lunCng sut ph bin hin nay cho dng UPS Offline v Line-interactive dao ng t 400VA n 2000VA, y l dy cng sut thp v trung bnh nn gi thnh thp. S chnh lch gi thnh gia 2 dng UPS l khng ng k, d chnh lch v hiu qu c th l 30-40%. Chnh v nhng l do trn nn mt s hng sn xut UPS ngng sn xut dng Offline, ch tp trung sn xut dng Line-Interactive v Online mang n li ch tt nht cho khch hng.Trong thi bui kinh t kh khn nh hin nay, vic la chn sn phm tt mang li hiu qu lu di tr thnh xu hng tt yu i vi doanh nghip. Do trong mi trng SOHO, cc doanh nghip cn mnh dn loi b nhng sn phm li thi trang b cho mnh nhng sn phm p dng cng ngh mi, mang li nhiu hiu qu. Thit ngh, vic phn tch cc li ch v hn ch ca tng dng UPS s gip cc doanh nghip d dng chn la c sn phm ph hp vi nhu cu ca mnh.

Trn Vn Thanh

18[ [ 11

Cc kin trc mng da

trn tiu chun ANSI/

TIA-942-A (phin bn

mi nht) cung cp

tr thp hn v bng

thng cao hn.

Ngun: Bo co IEEE 802.3 Bandwidth Assessment, thng 7/2012

Bng bo co IEEE Bandwidth Assessment thng 7/2012 c tnh: bng thng mng tng gp i mi 12 thng v bng thng server tng gp i mi 24 thng. Cc hng nghin cu IDC, DellOro Group v Crehan Research tng d on s lng cc server 10G s tng ln 50% vo nm 2014, v thc t hin tay, c th thy nhiu server 40G c s dng. o ha, mt cao, in ton m my v tr thp l nhng xu hng ch o trong trung tm d liu hin nay. Mt nghin cu th trng gn y cho thy, 40% server hin ti c o ha v 90% doanh nghip c ng thi chuyn sang o ha. M hnh kt ni ca cc ng dng cng chuyn sang chiu ngang (server-to-server hoc storage-to-storage) thay v chiu dc truyn thng (client-server). Mt bo co gn y ca Cisco d on, s c hn 15 t kt ni mng thc

hin vo nm 2015, i hi tc nhanh hn v cc ng dng phi c ti u ha. Trc nhu cu ngy cng thay i , xu hng v kin trc thit b cng phi thay i. Cc nh sn xut switch hng u pht trin nhng kin trc switch mi s dng cng 40G v 100G. Nhng dng switch mi ny ang c thit k vi tnh linh hot v mt cao hn. Kin trc 3 tng truyn thng c thit k h tr trung tm d liu trong nhiu nm trc khng cn l gii php l tng cho s pht trin h thng mng. Vi cc nhu cu ngy cng cao v o ha, in ton m my, tr thp, Hip hi Cng nghip Vin thng (TIA) pht hnh c t b sung tiu chun ANSI/TIA-942-A-1 vo thng 3/2013, m t cc khuyn ngh v cp vin thng h tr cc kin trc switch mi.

19652014

Trong kin trc 3 tng, cp MPO 12/24 si quang v dy nhy LC thng c dng kt ni gia switch core, switch aggregation v switch access. Kt ni t switch access v server c thc hin bng cp quang thng qua m-un SFP+ hoc cp ng bng dy nhy RJ45. Cc kt ni ny phc v cho ng dng 10GbE.

Vi kin trc full-mesh, tt c switch c u c kt ni cho vi nhau. V cc switch ny thng khng c s dng trong khu vc thit b (EDA) v m hnh top-of-rack (TOR), kin trc full-mesh ch ng dng trong cc trung tm d liu nh v trong mng metropolitan.

1/ Kin trc 3 tngtruyn thng

2/ Kin trc Full-Mesh

20[ [ 11

Kin trc fat-tree, hay cn gi l kin trc nhnh cy, l mt trong nhng kin trc thay th cho kin trc truyn thng. Kin trc fat-tree thc hin kt ni gia cc switch interconnection (switch trc) v switch access (switch l) h tr h thng my tnh cluster hiu sut cao. to m hnh mng phng v d dng m rng lp 2, kin trc fat-tree s dng cu trc non-blocking, tr thp. Kiu kin trc ny thng c trin khai trong cc trung tm d liu ln. Trong hnh minh ha, switch interconnection kt ni trc tip vi switch access thng qua dy trunk MTP 12/24 si quang v module chuyn i (24 si quang) hoc adapter MTP (12 si quang). So vi m hnh ba lp truyn thng, kin trc fat-tree s dng t

switch aggregation v ng d phng hn h tr 40GBase-SR gia switch access v interconnection, nh gim tr v t tiu tn in nng hn. Cc kin trc full-mesh, interconnected-mesh, switch tp trung v switch o l nhng kin trc h tr cho tiu chun ANSI/TIA-942-A-1. Cng nh fat-tree, nhng kin trc switch mi ny gim tr tt hn v cung cp bng thng cao hn so vi m hnh truyn thng, k c trn cng non-blocking.

Trong kin trc tp trung, server c kt ni vi tt c switch v d dng qun l t mt server bt k. D vy, s lng cng hn ch c th cn tr vic m

rng kin trc ny. Do , kin trc tp trung cng ch c p dng trong cc trung tm d liu nh, tng t nh full-mesh.

3/ Kin trc Fat-Tree

4/ Kin trctp trung

21652014

Kin trc virtual-switch xut pht t nguyn l ca kin trc tp trung, s dng nhiu switch kt ni vi nhau to thnh mt switch o. Mi server c kt ni vo nhiu switch to ng d phng, nhng cng to ra tr. Kin trc virtual-switch khng h tr kh nng m rng tt d gia cc switch o trin khai kin trc fat-tree hoc full-mesh.

Tng t kin trc full-mesh, kin trc interconnection-mesh c tnh m rng cao hn, gip gim chi ph v d dng trin khai cho cc doanh nghip ang pht trin. Interconnection-mesh thng c t 1 n 3 switch interconnection (HDA hoc EDA) v non-blocking ti mi nhm.

5/ Kin trc interconnected-mesh

Nhng kin trc mi mang li kh nng thit k linh hot v d dng m rng quy m. Cp MTP/MPO 12/24 fiber bm sn l cng c h tr l tng cho cc kt ni bng thng cao trong trung tm d liu, m bo tn dng h tng cp ti u. Ngoi ra, cc si cp ny cn c th h tr ng dng 40G v 100G trong tng lai theo c t ANSI/TIA-942-A-1. h tr nhng kin trc mi, IEEE ang pht trin nhng c t k thut mi cho lp vt l. Tiu chun IEEE P802.3bm ang c pht trin h tr cc cng ngh 40/100 GbE vi chi ph thp, tit kim in nng v tng mt s dng. Tiu chun ny d kin s c gii thiu vo qu I nm 2015. Bn cnh , nhm nghin cu v IEEE 802.3 400G cng c thnh lp t thng 3/2013 vi mc tiu OM3 hoc OM4 h tr 400G, s dng 25G trn mt knh- tng t nh

chun P802.3bm. Tiu chun mi ny d kin hon thnh vo nm 2017. Vic pht trin nhng tiu chun mi l iu cn thit p ng nhu cu tc truyn dn ngy cng cao. Do , vic thit k cng phi linh hot tng thch vi yu cu m rng v pht trin. Nm r nhng kin trc v tiu chun ny gip trung tm d liu ca bn sn sng cho vic di chuyn ln 40G, 100G hoc thm ch cao hn. Quan trng hn, rt cn nhng chuyn gia thc s hiu v mi trng cng nh xu hng pht trin kin trc trung tm d liu h tr doanh nghip trong vic nng cp h thng mng.

Lu L Qui NhnTheo Cabling Installation & Maintenance

6/ Kin trcvirtal-switch

KT LUN