LI NOI U

LI NOI UTh gii ngy nay c nhiu tin b mnh m v cng ngh thng tin (CNTT) t mt tim nng thng tin tr thnh mt ti nguyn thc s, tr thnh sn phm hng ho trong x hi to ra mt s thay i to ln trong lc lng sn xut, c s h tng, cu trc kinh t, tnh cht lao ng v c cch thc qun l trong cc lnh vc ca x hi. Vi s pht trin nn cng ngh thng tin nh vy, vic ng dng CNTT vo i sng hng ngy tr nn qu quen thuc vi mi ngi. Vi s pht trin nh vy mng Internet pht trin mnh m, lm thay thay i nhng thi quen trong x hi, n mang li li ch to ln cho cho qu trnh pht trin kinh t x hi, thng tin lin lc ca con ngi.

Internet pht trin nh v bo nh vy, vi hng trm triu my tnh trn mng so vi ch vi trm my ban u. Trong khi vic to ra mt h thng mng kh m vic qun l h thng mng li cng kh khn hn. gii quyt nhng vn ny phi s dng phn mm Cacti qun l h thng mng mt cch hp l hn.

nhn thy c v hiu r hn s quan trng trong vic qun l mt h thng mng mt cch hp l th nhm 5 lp MM02A tin hnh nghin cu v phn tch cc vn v giao thc SNMP v qun l h thng mng vi Cacti.MC LC

1CHNG 1:TNG QUAN V QUN L MNG VI GIAO THC SNMP

11.1.KHI NIM QUAN L MANG

31.2.GIAO THC QUAN L MANG SNMP

31.2.1.Gii Thiu v Giao thc SNMP

41.2.2.u im v cc phin bn giao thc SNMP

41.2.2.1.u im s dng giao thc SNMP

41.2.2.2.Cc phin bn giao thc SNMP

121.2.3.Qun l truyn thng trong SNMP.

131.2.3.1.B phn qun l (manager).

141.2.3.2.Agent.

141.2.3.3.C s thng tin qun l MIB.

151.2.3.4.M hnh giao thc SNMP.

201.2.4.Cc thnh phn trong giao thc SNMP

201.2.5.Cc c ch bo mt SNMP.

22CHNG 2:TRIN KHAI QUN L MNG VI PHN MM CACTI

222.1.GII THIU V CACTI.

222.2.M HNH TRIN KHAI.

232.3.CI T CACTI.

242.4.CU HNH CACTI.

242.4.1.Thm Thit bi quan ly.

262.4.2.Tao graphs quan ly theo s .

262.4.3.Quan ly c ban h thng.

32KT LUN

CHNG 1: TNG QUAN V QUN L MNG VI GIAO THC SNMP

1.1. KHI NIM QUAN L MANG

Cc c ch qun l mng c nhn nhn t hai gc , gc mng ch ra h thng qun l nm ti cc mc cao ca m hnh OSI v t pha ngi iu hnh qun l h thng. Mc d c rt nhiu quan im khc nhau v m hnh qun l nhng chng u thng nht bi ba chc nng qun l c bn gm: gim st, iu khin v a ra bo co ti ngi iu hnh.

Chc nng gim st c nhim v thu thp lin tc cc thng tin v trng thi ca cc ti nguyn c qun l sau chuyn cc thng tin ny di dng cc s kin v a ra cc cnh bo khi cc tham s ca ti nguyn mng c qun l vt qu ngng cho php.

Chc nng qun l c nhim v thc hin cc yu cu ca ngi qun l hoc cc ng dng qun l nhm thay i trng thi hay cu hnh ca mt ti nguyn c qun l no .

Chc nng a ra bo co c nhim v chuyn i v hin th cc bo co di dng m ngi qun l c th c, nh gi hoc tm kim, tra cu thng tin c bo co.

Trong thc t, tu theo tng cng vic c th m cn c mt vi chc nng khc c kt hp vi cc h thng qun l v cc ng dng qun l c s dng nh qun l k hoch d phng thit b, dung lng, trin khai dch v, qun l tm tt ti nguyn, qun l vic phn phi ti nguyn mng cc h thng, qun l vic sao lu v khi phc tnh trng h thng, vn hnh qun l t ng. Phn ln cc chc nng phc tp k trn u nm trong hoc c xy dng da trn nn tng ca ba chc nng qun l lp cao l gim st, iu khin v a ra bo co.

Hin nay c hai phng php qun l mng c s dng kh ph bin l qun l mng tp trung v qun l mng phn cp.

i vi hnh thc qun l mng tp trung: Ch c mt thit b qun l thu nhn cc thng tin v iu khin ton b cc thc th mng. Cc chc nng qun l c thc hin bi manager, kh nng ca h thng ph thuc rt ln vo mc thng minh ca manager. Kin trc ny thng c s dng rt nhiu v c trung tm qun tr mng. So vi cc chc nng thuc manager chc nng Agent thng rt n gin, thng tin trao i t manager ti cc agent thng qua cc giao thc thng tin qun l nh giao thc SNMP (Simple Network Management Protocol). Tuy nhin h thng qun l tp trung rt kh m rng v mc phc tp ca h thng tng.

u im: Quan st cnh bo v cc s kin mng t mt v tr. Bo mt c khoanh vng n gin.

Nhc im: Li h thng qun l chnh s gy tc hi ti ton b mng. Tng phc tp khi c thm cc phn t mi vo mng.

i vi phng thc qun l phn cp: H thng c chia thnh cc vng ty theo nhim v qun l to ra h thng phn cp qun l. Trung tm x l t ti gc ca cy phn cp, cc h thng phn tn c t ti nhnh cy.

u im: C kh nng m rng h thng qun l nhanh.

Nhc im: Danh sch thit b qun l phi c xc nh v cu hnh trc.

1.2. GIAO THC QUAN L MANG SNMP1.2.1. Gii Thiu v Giao thc SNMP

Vo u nm 1988, T chc kin trc Internet IAB (Internet Architecture Board) nhn thy s cn thit c b cng c qun l cho TCP/IP nn cho ra i RFC 1052.RFC 1052 l cc yu cu tiu chun ho qun l mng v tp trung vo cc vn qun l mng phi thc hin:

m bo tnh m rng

m bo tnh a dng pht trin

m bo tnh a dng trong qun l

Bao trm nhiu lp giao thc

Thng 4 nm 1993, SNMPv2 tr thnh tiu chun qun l mng n gin thay th SNMPv1. SNMPv2 b sung mt s vn m SNMPv1 cn thiu nh nhn thc v bo mt. Tuy nhin, SNMPv2 kh phc tp v kh tng thch vi SNMPv1.

Nm 1997, SNMPv3 ra i nhm tng thch vi cc giao thc a phng tin trong qun l mng, pht trin trn nn java v a ra kin trc v giao thc mi nh giao thc qun l a phng tin HMMP (Hypermedia Management Protocol).1.2.2. u im v cc phin bn giao thc SNMP

1.2.2.1. u im s dng giao thc SNMP

SNMP c thit k n gin ha qu trnh qun l cc thnh phn trong mng. Nh cc phn mm SNMP c th c pht trin nhanh v tn t chi ph. SNMP c thit k c th m rng cc chc nng qun l, gim st. Khi c mt thit b mi vi cc thuc tnh, tnh nng mi th ngi ta c th thit k ty chn SNMP phc v cho ring mnh. SNMP c thit k c th hot ng c lp vi cc kin trc v c ch ca cc thit b h tr SNMP.Cc thit b khc nhau c hot ng khc nhau nhng hot ng da trn giao thc SNMP l ging nhau.

1.2.2.2. Cc phin bn giao thc SNMP

Hin ti SNMP c 3 phin bn : SNMPv1, SNMPv2 v SNMPv3. Cc phin bn ny khc nhau mt cht nh dng bn tin v phng thc hot ng. Hin nay SNMPv1 l ph bin nht do c nhiu thit b tng thch nht v c nhiu phn mm h tr nht. Trong khi ch c mt s thit b v phn mm h tr SNMPv3.

-Phin bn SNMPv1: phin bn u tin ca SNMP, c 5 phng thc Get, GetNext, Set, Response, Trap. GetRequest : Bn tin GetRequest c manager gi n agent ly mt thng tin no . Trong GetRequest c cha ID ca object mun ly. V d: Mun ly thng tin tn ca Device1 th manager gi bn tin GetRequest ID=1.3.6.1.2.1.1.5 n Device1, tin trnh SNMP agent trn Device1 s nhn c bn tin v to bn tin tr li. Trong mt bn tin GetRequest c th cha nhiu OID, ngha l dng mt GetRequest c th ly v cng lc nhiu thng tin. GetNextRequest: Bn tin GetNextRequest cng dng ly thng tin v cng c cha OID, tuy nhin n dng ly thng tin ca object nm k tip object c ch ra trong bn tin. Chung ta bit khi c qua nhng phn trn: mt MIB bao gm nhiu OID c sp xp th t nhng khng lin tc, nu bit mt OID th khng xc nh c OID k tip. Do ta cn GetNextRequest ly v gi tr ca OID k tip. Nu thc hin GetNextRequest lin tc th ta s ly c ton b thng tin ca agent. SetRequest: Bn tin SetRequest c manager gi cho agent thit lp gi tr cho mt object no . V d: C th t li tn ca mt my tnh hay router bng phn mm SNMP manager, bng cch gi bn tin SetRequest c OID l 1.3.6.1.2.1.1.5.0 (sysName.0) v c gi tr l tn mi cn t. GetResponse: Mi khi SNMP agent nhn c cc bn tin GetRequest, GetNextRequest hay SetRequest th n s gi li bn tin GetResponse tr li. Trong bn tin GetResponse c cha OID ca object c request v gi tr ca object . Trap: Bn tin Trap c agent t ng gi cho manager mi khi c s kin xy ra bn trong agent, cc s kin ny khng phi l cc hot ng thng xuyn ca agent m l cc s kin mang tnh bin c. V d: Khi c mt port down, khi c mt ngi dng login khng thnh cng, hoc khi thit b khi ng li, agent s gi trap cho manager. Tuy nhin khng phi mi bin c u c agent gi trap, cng khng phi mi agent u gi trap khi xy ra cng mt bin c. Vic agent gi hay khng gi trap cho bin c no l do hng sn xut device/agent quy nh.

Cu trc ca PDU GetRequest: + Request-id : m s ca request. ID ny l s ngu nhin do manager to ra, agent khi gi bn tin GetResponse cho request no th n phi gi requestID ging nh lc nhn. Gia manager v agent c th c nhiu request & reponse, mt request v mt response l cng mt phin trao i khi chng c requestID ging nhau.

+ Error-status : nu = 0 l thc hin thnh cng khng c li, nu 0 l c li xy ra v gi tr ca n m t m li. Trong bn tin GetRequest, GetNextRequest, SetRequest th error-status lun = 0.

+ Error-index : s th t ca objectid lin quan n li nu c. Trong variable-bindings c nhiu objectid, c nh s t 1 n n, mt bn tin GetRequest c th ly cng lc nhiu object.

+ Variable-bindings : danh sch cc cp [ObjectID Value] cn ly thng tin, trong objectId l nh danh ca object cn ly, cn value khng mang gi tr. Khi agent gi bn tin tr li th n s copy li bn tin ny v in vo value bng gi tr ca object.

Trong hnh trn l cu trc mt bn tin SNMP vi PDU l GetRequest. Bao gm cc thng tin :

+ Version l v1, s 0 trong ngoc l gi tr ca trng version, nu gi tr ny l 0 ngha l version1.

+ Community l public.

+ Request-id = 2142061952.

+ Error-status = 0, ngha l khng c li. Trong bn tin GetResponse th error-status mi c dng.

+ Error-index = 0.

+ Phn variable-bindings bao gm 1 item, mi item l 1 cp objectid-value.

+ Objectid l .1.3.6.1.2.1.1.3.0, theo mib-2 th l sysUpTime.0

+ Scalar instance index = 0, y l ch s index ca sysUptime. Do mt thit b ch c mt khi nim sysUptime nn index l 0 (sysUptime.0). Nu bn request ifDescr chng hn th mi interface s c mt description khc nhau v s c index khc nhau.

+ value = unSpecified. Do bn tin l GetRequest nn value s khng mang gi tr, gi tr s c ghi vo v tr v trong bn tin GetResponse.

Cu trc ca PDU GetResponse: Cu trc GetNextRequest ging vi GetRequest, ch khc byte ch ra bn tin l GetNextRequest PDU. Hnh sau l bn tin GetNextRequest vi objectid l sysContact, sau agent s gi bn tin GetReponse tr li vi Objectid l sysName, v sysName nm sau sysContact trong MIB. Ch request-id l ging nhau.

Cu trc ca PDU SetRequest: Cu trc SetRequest cng ging vi GetRequest, objectid-value ch ra i tng v gi tr cn set.

Cu trc ca PDU Trap: Cu trc ca bn tin trap ca SNMPv1 nh sau :

+ Enterprise : kiu ca object gi trap. y l mt OID gip nhn dng thit b gi trap l thit b g; nhn dng chi tit n hng sn xut, chng loi, model. OID ny bao gm mt ch s doanh nghip (enterprise number) v ch s id ca thit b ca

hng do hng t nh ngha.

+ Agent address : a ch IP ca ngun sinh ra trap. C th bn s thc mc ti sao li c IP ca ngun sinh ra trap trong khi bn tin IP cha gi SNMP c a ch ngun. Gi s m hnh gim st ca bn nh sau : tt c trap sender c cu hnh gi trap n mt trap receiver trung gian, gi l trap relay, sau trap relay mi gi n nhiu trap receiver cng lc th lc ny bn tin trap nhn c ti trap receiver s c IP source l ca trap relay, trong khi IP ca ngun pht sinh trap thc s nm trong agent address.

+ Generic-trap: kiu ca cc loi trap generic.

+ Specific-trap: kiu ca cc loi trap do ngi dng t nh ngha.

+ Time-stamp: thi gian tnh t lc thit b c khi ng n lc gi bn tin trap, tnh bng centi giy.

+ Variable-bindings: cc cp objectID values m t cc object c lin quan n trap.- Phin bn SNMPv2: SNMPv2 tch hp kh nng lin iu hnh t manager ti manager v hai n v d liu giao thc mi. Kh nng lin kt iu hnh manager-manager cho php SNMP h tr qun l mng phn tn trong mt trm v gi bo co ti mt trm khc. Hai n v d liu giao thc PDU (Protocol Data Unit) l GetbulkRequest v InformRequest. Cc PDU ny lin quan ti x l li v kh nng m ca SNMPv2. Kh nng m trong SNMPv2 s dng b m 64 bit (hoc 32) duy tr trng thi ca cc lin kt v giao din.

MIB cho SNMPv2: MIB trong SNMPv2 nh ngha cc i tng m t tc ng ca mt phn t SNMPv2.MIB gm 3 nhm:

Nhm h thng (System group): l mt m rng ca nhm system trong MIB-II gc, bao gm mt nhm cc i tng cho php mt Agent SNMPv2 m t cc i tng ti nguyn ca n.

Nhm SNMP (SNMP group): mt ci tin ca nhm SNMP trong MIB-II gc, bao gm cc i tng cung cp cc cng c c bn cho hot ng giao thc.

Nhm cc i tng MIB (MIB objects group): mt tp hp cc i tng lin quan n cc SNMPv2-trap PDU v cho php mt vi phn t SNMPv2 cng hot ng, thc hin nh trm qun tr, phi hp vic s dng ca chng trong ton t Set ca SNMPv2

Nhm h thng: nhm system nh ngha trong SNMPv2 ging trong MIB-II v b sung mt vi i tng mi.

Nhm SNMP: Nhm ny gn ging nh nhm SNMP c nh ngha trong MIB-II nhng c thm mt s i tng mi v loi b mt s i tng ban u. Nhm SNMP cha mt vi thng tin lu lng c bn lin quan n ton t SNMPv2 v ch c mt trong cc i tng l b m ch c 32-bit.

Nhm i tng MIB: Nhm cc i tng MIB cha cc i tng thch hp thm vo vic iu khin cc i tng MIB.

Cu trc bn tin SNMPv2 :

Trng phin bn (Version) th hin phin bn ca giao thc SNMPv2.

Trng Community l mt chui password xc nhn cho c tin trnh ly v thay i d liu. SNMP PDU cha kiu iu hnh (get, set), yu cu p ng (cng s th t vi bn tin gi i) - cho php ngi iu hnh gi ng thi nhiu bn tin. Bin ghp gm cc thit b c c t trong RFC 2358 v cha c gi tr t ti i tng.

Trng n v d liu giao thc (PDU) gm c cc trng con: Kiu n v d liu giao thc, nhn dng cc yu cu (Request ID), trng thi li, ch s li, cc gi tr v i tng.

Cc kiu n v d liu giao thc PDU th hin cc bn tin s dng trong SNMPv2 gm c:

GetRequest: Cu lnh GetRequest c s dng gia Manager ti Agent. Cu lnh ny c s dng c bin MIB n hoc danh sch cc bin MIB t cc Agent ch.

GetNextRequest: Cu lnh GetNextRequest tng t nh cu lnh GetRequest, tuy nhin tu thuc vo agent trong khon mc k tip ca MIB. Cc bin c lu trong thit b v c coi nh i tng b qun l. V vy,cu lnh GetNextRequest m rng cc bin v c c theo tun t.

SetRequest: Cu lnh SetRequest l cu lnh c gi i t Manager ti Agent nh hai cu lnh trn. SetRequest tm kim cc thng tin m rng trongbng MIB v yu cu Agent t gi tr cho cc i tng qun l hoc cc i tng cha trong cu lnh.

GetResponse: Cu lnh GetResponse l cu lnh t Agent ti Manager. Cu lnh ny cung cp c ch p ng cho cc cu lnh GetRequest, GetNextRequest v SetRequest.

Trap: Trap l cu lnh c lp, khng ph thuc vo p ng hoc yu cu tcc Manager hoc cc Agent. Trap a ra cc thng tin lin quan ti cc iu kin c nh ngha trc v c gi t cc Agent ti Manager.

GetBulkRequest: Chc nng ca cu lnh GetBulkRequest tng t nh cu lnh GetNextRequest ngoi tr vn lin quan ti s lng d liu c ly ra. GetBulkRequest cho php Agent gi li Manager d liu lin quan ti nhiu i tng thay v tng i tng b qun l. Nh vy, GetBulkRequest c th gim bt lu lng truyn dn v cc bn tin p ng thng bo v cc iu kin vi phm.

InformRequest: Cu lnh InformRequest cung cp kh nng h tr cc Manager b tr theo cu hnh phn cp.Cu lnh ny cho php mt Manager trao i thng tin vi cc Manager khc.

Trong trng PDU Type, cc gi tr th hin nh sau:

- Phin bn SNMPv3: SNMPv3 da trn vic thc hin giao thc, loi d liu v u quyn nh SNMPv2 v ci tin phn an ton. SNMPv3 cung cp an ton truy nhp vo cc thit b bng cch kt hp s xc nhn v m kho cc gi tin trn mng. Nhng c im bo mt cung cp trong SNMPv3 l:

Tnh ton vn thng tin : m bo cc gi tin khng b sa trong khi truyn.

S xc nhn: Xc nhn ngun ca thng tin gi n.

M kho: o ni dung ca gi tin, ngn cn vic gi thng bo t ngun khng c xc nhn.

Tuy nhin vic s dng SNMPv3 rt phc tp v cng knh d n l s la chn tt nht cho vn bo mt ca mng. Vic s dng s tn rt nhiu ti nguyn do trong mi bn tin truyn i s c phn m ha BER. Phn m ha ny s chim mt phn bng thng ng truyn do lm tng ph tn mng. Mc d c coi l phin bn ngh cui cng v c coi l y nht nhng SNMPv3 vn ch l tiu chun d tho v vn ang c nghin cu hon thin.

Khun dng bng tin SNMPv3: RFC 2572 nh ngha cc khun dng bn tin SNMPv3. Khun dng bn tin SNMPv3 c phn chia trong trong bn phn

D liu chung (Common data)- Trng ny xut hin trong tt c cc bn tin SNMPv3.

Bo mt m hnh d liu (Security model data)- Vng ny c ba phn: phn chung, phn dnh cho s chng thc v phn cho d liu ring.

Context Hai trng nhn dng v tn c dng cung cp context cho PDU no s phi x l.

PDU Vng ny cha mt SNMPv2c PDU.1.2.3. Qun l truyn thng trong SNMP.

H thng qun l mng da trn SNMP gm ba thnh phn: b phn qun l(manager), thit b chu s qun l cn gi l i l (agent) v c s d liu gi l C s thng tin qun l (MIB). Mc d SNMP l mt giao thc qun l vic chuyn giao thng tin gia ba thc th trn, song n cng nh ngha mi quan h client-server (ch t). C s d liu do agent SNMP qun l l i din cho MIB ca SNMP. Minh ha mi quan h gia ba thnh phn SNMP ny.

1.2.3.1. B phn qun l (manager).

B phn qun l l mt chng trnh vn hnh trn mt hoc nhiu my tnh trm.

Ty thuc vo cu hnh, mi b phn qun l c th c dng qun l mt mng con, hoc nhiu b phn qun l c th c dng qun l cng mt mng con hay mt mng chung. Tng tc thc s gia mt ngi s dng cui (end-user) v b phn qun l c duy tr qua vic s dng mt hoc nhiu chng trnh ng dng m, cng vi b phn qun l, bin mt bng phn cng thnh trm qun l mng (NMS). Ngy nay, trong thi k cc chng trnh giao din ngi s dng ha (GUI), hu ht nhng chng trnh ng dng s cho ra giao din s dng con tr v chut phi hp hot ng vi b phn qun l to ra nhng bn ha v biu cung cp nhng tng kt hot ng ca mng di dng thy c. Qua b phn qun l, nhng yu cu c chuyn ti mt hoc nhiu thit b chu s qun l ban u SNMP c pht trin s dng trn mng TCP/IP v nhng mng ny tip tc lm mng vn chuyn cho phn ln cc sn phm qun l mng da trn SNMP. Tuy nhin SNMP cng c th c chuyn qua NetWare IPX v nhng c cu vn chuyn khc.

1.2.3.2. Agent.

Thit b chu s qun l (Agent) l mt nt mng h tr giao thc SNMP v thuc v mng b qun l. Thit b c nhim v thu thp thng tin qun l v lu tr phc v cho h thng qun l mng. Nhng thit b chu s qun l, i khi c gi l nhng phn t mng, c th l cc b nh tuyn v my ch truy nhp (Access Server), switch, bridge, hub v my tnh hay l my in trong mng. Mi thit b chu s qun l bao gm phn mm hoc phn sn (firmware) di dng m phin dch nhng yu cu SNMP v p ng ca nhng yu cu . Phn mm hoc phn sn ny c coi l mt agent. Mc d mi thit b bt buc bao gm mt agent chu qun l trc tip, nhng thit b khng tng thch vi SNMP cng c th qun l c nu nh chng h tr mt giao thc qun l c quyn. thc hin c iu ny phi c agent y nhim (proxy agent). Proxy agent ny c th c coi nh mt b chuyn i giao thc v n phin dch nhng yu cu SNMP thnh giao thc qun l c quyn ca thit b khng hot ng theo giao thc SNMP. Mc d SNMP ch yu l giao thc p ng thm d (poll-respond) vi nhng yu cu do b phn qun l to ra dn n nhng p ng trong agent, agent cng c kh nng xng ra mt p ng t nguyn. p ng t nguyn ny l iu kin cnh bo t vic gim st agent vi hot ng c nh ngha trc v p ng ny cnh bo vic agent ti ngng nh trc. Di s iu khin SNMP, vic truyn cnh bo ny c gi l ci by (TRAP).1.2.3.3. C s thng tin qun l MIB.

Mi thit b chu s qun l c th c cu hnh, trng thi v thng tin thng k nh ngha chc nng v kh nng vn hnh ca thit b. Thng tin ny rt a dng, c th bao gm vic thit lp chuyn mch phn cng, nhng gi tr khc nhau lu tr trong cc bng ghi nh d liu, b h s hoc cc trng thng tin trong h s lu tr cc file v nhng bin hoc thnh phn d liu tng t. Nhn chung, nhng thnh phn d liu ny c coi l C s thng tin qun l ca thit b chu s qun l. Xt ring, mi thnh phn d liu bin i c coi l mt i tng b qun l v bao gm tn, mt hoc nhiu thuc tnh v mt tp cc hot ng (operation) thc hin trn i tng . V vy MIB nh ngha loi thng tin c th khi phc t mt thit b chu s qun l v cch ci t thit b m h thng qun l iu khin.1.2.3.4. M hnh giao thc SNMP.

SNMP s dng cc dch v chuyn ti d liu thng qua cc giao thc UDP/IP. Mt ng dng ca Manager phi nhn dng c Agent cn thng tin vi n. Mt ng dng ca Agent c nhn dng bi a ch IP ca n v mt cng UDP. Mt ng dng Manager ng gi yu cu SNMP trong mt UDP/IP, UDP/IP cha m nhn dng cng ngun, a ch IP ch v m nhn dng cng UDP ca n. Khung UDP s c gi i thng qua thc th IP ti h thng chu s qun l, ti khung UDP s c phn phi bi thc th UDP ti Agent. Tng t, cc bn tin TRAP phi c cc Manager nhn dng. Cc bn tin s dng a ch IP v m nhn dng cng UDP ca Manager SNMP. SNMP s dng 3 lnh c bn l Read, Write, Trap v mt s lnh ty bin qun l thit bLnh Read: c SNMP dng c thng tin t thit b. Cc thng tin ny

c cung cp qua cc bin SNMP lu tr trn thit b v c thit b cp nht.

Lnh Write: c SNMP dng ghi cc thng tin iu khin ln thit b bng cch thay i gi tr cc bin SNMP.

Lnh Trap: Dng nhn cc s kin gi t thit b n SNMP. Mi khi c

mt s kin xy ra trn thit b mt lnh Trap s c gi ti NMS.

SNMP iu khin, theo di thit b bng cch thay i hoc thu thp thng tin qua cc bin gi tr lu trn thit b. Cc Agent ci t trn thit b tng tc vi nhng chip iu khin h tr SNMP ly ni dung hoc vit li ni dung.

Giao thc SNMP s dng kiu kt ni v hng (connectionless) trao i thng tin gia cc phn t v h thng qun l mng (c th l UDP - User Datagram Protolcol - Giao thc d liu ngi s dng). UDP truyn cc gi tin theo cc khi ring bit. Tuy vy c th ty s dng cc giao thc khc truyn cc gi tin SNMP. Khi gi cc gi tin qua mng, cc phn t mng hay h thng qun l mng vn gi nguyn nh dng ca SNMP.

Ta thy, SNMP thuc v lp ng dng trong m hnh giao thc, n s dng UDP lm

giao thc lp vn chuyn trn mng IP.

Qun l lin lc gia manager vi cc agent: Nhn trn phng din truyn thng, manager v cc agent cng l nhng ngi s dng, s dng mt giao thc ng dng. Giao thc qun l yu cu c ch vn chuyn h tr tng tc gia cc agent v manager. Manager trc ht phi xc nh c cc agent m n mun lin lc. C th xc nh c ng dng agent bng a ch IP ca n v cng UDP c gn cho n. Cng UDP 161 c dnh ring cho cc agent SNMP. Manager gi lnh SNMP vo mt tiu UDP/IP. Tiu ny cha cng ngun, a ch IP ch v cng 161. Mt thc th IP ti ch s chuyn giao gi UDP ti h thng b qun l. Tip , mt thc th UDP ti ch s chuyn pht n ti cc agent. Tng t nh vy, lnh TRAP cng cn xc nh nhng manager m n cn lin h. Chng s dng a ch IP cng nh cng UDP dnh cho SNMP manager, l cng 162.

C ch vn chuyn thng tin gia manager v agent: Vic la chn c ch vn chuyn l c lp vi giao thc truyn thng . SNMP ch i hi c ch vn chuyn khng tin cy d liu (datagram) truyn a cc PDU (n v d liu giao thc) gia manager v cc agent. iu ny cho php s nh x ca SNMP ti nhiu nhm giao thc. M hnh vn chuyn datagram gim c phc tp ca nh x tng vn chuyn. Tuy nhin, vn c mt s la chn cho tng vn chuyn. Cc tng vn chuyn khc nhau c th s dng nhiu k thut nh a ch khc nhau. Cc tng vn chuyn khc nhau c th a ra nhng hn ch quy m ca PDU. nh x tng vn chuyn c trch nhim phi x l cc vn nh a ch, hn ch quy m PDU v mt s tham s tng vn chuyn khc. Trong phin bn th hai ca SNMP, ngi ta n gin ha qu trnh nh x ti cc chun vn chuyn khc nhau. Giao thc qun l c tch khi mi trng vn chuyn v iu ny cng c khuyn khch s dng cho bt c nhm giao thc no.Bo v truyn thng lin lc gia manager v cc agent khi s c: Trong iu kin mng thiu n nh v tin cy th vic truyn thng qun l cng tr nn quan trng. Lm th no cc manager lin lc vi cc agent mt cch tin cy? Vic SNMP s dng c ch UDP lin lc lm thiu i tin cy v UDP hot ng theo kiu d liu . SNMP li cho chng trnh manager hon ton chu trch nhim v x l vic mt thng tin. Cc lnh GET, GET-NEXT v SET u c phc p bng mt lnh GET-RESPONSE. H thng c th d dng pht hin ra vic b mt mt lnh khi khng nhn c lnh tr li. N c th lp li yu cu mt ln na hoc c nhng hnh ng khc. Tuy nhin, cc bn tin TRAP do agent to ra li khng yu cu phc p. Khi b tht lc bn tin TRAP, cc chng trnh agent s khng bit c iu (tt nhin l manager cng khng hay bit v iu ny). Thng thng cc bn tin TRAP mang nhng thng tin ht sc quan trng cho manager, do vy manager cn ch v cn bo m vic vn chuyn chng mt cch tin cy. Mt cu hi t ra l lm th no vn chuyn m trnh c mt mt, tht lc cc bn tin TRAP? Ta c th thit k cho cc agent gi lp li bn tin TRAP. Bin s MIB c th c s ln lp li theo yu cu. Lnh SET ca manager c th t cu hnh cho bin s ny. C mt cch khc l agent c th lp li lnh TRAP cho n khi manager t bin s MIB chm dt s c. Tuy nhin, c hai phng php trn u ch cho ta nhng gii php tng phn. Trong trng hp th nht, s ln lp li c th khng m bo lin lc mt cch tin cy. Trong trng hp th hai, mt s c mng c th dn n vic hng lot bn tin TRAP b mt ty thuc vo tc m cc agent to ra chng. iu ny lm cho s c mng tr nn trm trng hn. Trong c hai trng hp, nu ta cn chuyn nhng bn tin TRAP ti nhiu manager th c th xy ra tnh trng khng nht qun gia cc manager hoc xy ra hin tng tht lc thng tin rt phc tp. Nu cc agent phi chu trch nhim thit k cho vic phc hi nhng bn tin TRAP th cng lm tng thm phc tp trong vic qun l cc agent trong mi trng a nh ch to. Ngi ta cng c gng ci tin c ch x l bn tin s c cho phin bn th hai ca SNMP. Th nht l n nguyn TRAP c b i v thay th n bng mt lnh GET/RESPONSE. Lnh ny do agent to ra v chuyn n cho manager by ti cng UDP-162. iu ny phn nh quan im l b phn qun l s c c th thng nht cc bn tin s c ri tr li cho cc yu cu o. Bng cch b i mt n th, giao thc c n gin ha. Ngi ta cng b sung thm mt c s thng tin qun l c bit TRAP MIB thng nht vic x l s c, cc manager nhn bn tin v cc s c ny v vic lp li c thc hin ci thin tin cy trong vic vn chuyn thng tin.nh hng ca tng vn chuyn ti kh nng qun l mng: Vic s dng mng b qun l h tr cc nhu cu thng tin lin lc qun l (qun l trong bng) gy ra nhiu vn th v. Vic qun l trong bng v ngoi bng c lp vi vic la chn giao thc qun l. Qun l trong bng c th dn n tnh trng mt lin lc vi mt agent ng lc agent cn s ch v qun l (ty thuc vo ngun ca s c). Ngi ta c th lm gim nh c vn ny nu chnh cc thc th m agent qun l li bo v ng truy nhp ti cc agent ny. C mt nh hng nh v kh nng qun l xut hin trong vic nh a ch tng vn chuyn. V d: c th xc nh duy nht mt agent SNMP bng a ch IP v s cng UDP. iu ny c ngha l vi mt a ch IP cho trc th ta ch c th tip cn c mt agent duy nht. Hn th na agent ny li ch duy tr mt c s thng tin qun l MIB duy nht. Do vy, vi mt a ch IP duy nht ch tn ti mt MIB. Vic gn kt MIB vi a ch IP c th hn ch c phc tp ca bin s liu m agent cung cp. Xem xt trong cng mt hon cnh trong h thng yu cu nhiu MIB qun l cc thnh phn khc nhau ca n. Cn phi thng nht cc MIB khc nhau ny di mt cy MIB tnh duy nht c th truy nhp chng thng qua mt agent duy nht. Trong mt s hon cnh nht nh, vic thng nht khng th thc hin c. Trong nhng trng hp nh vy, mi MIB i hi phi c ring mt nhm giao thc SNMP/UDP/IP. iu ny lm tng phc tp trong vic t chc qun l (cc thng tin tng quan t nhiu MIB thuc mt h thng cho trc) cng nh vic truy nhp n (thng qua nhiu a ch IP). C mt cch khc l mt agent duy nht trong mt h thng c th gi vai tr nh mt proxy m rng cho cc agent ph ng gi nhng c s d liu MIB khc nhau cng lin quan ti mt phn h cho trc. Cc phin bn m rng SNMPv2 h tr phng php ny x l nhu cu truyn thng ca manager. Cc phin bn m rng ny cho php agent ng vai tr nh mt manager ca cc agent con ti ch, do vy cho php tip cn hng lot cc agent con.1.2.4. Cc thnh phn trong giao thc SNMP

Kin trc ca SNMP bao gm 2 thnh phn : cc trm qun l mng (network management station) v cc thnh t mng (network element). Network management station thng l mt my tnh chy phn mm qun l SNMP (SNMP management application), dng gim st v iu khin tp trung cc network element Network element l cc thit b, my tnh, hoc phn mm tng thch SNMP v c qun l bi network management station. Nh vy element bao gm device, host v application. Mt management station c th qun l nhiu element, mt element cng c th c qun l bi nhiu management station. Vy nu mt element c qun l bi 2 station th iu g s xy ra? Nu station ly thng tin t element th c 2 station s c thng tin ging nhau. Nu 2 station tc ng n cng mt element th element s p ng c 2 tc ng theo th t ci no n trc. Ngoi ra cn c khi nim SNMP agent. SNMP agent l mt tin trnh (process) chy trn network lement, c nhim v cung cp thng tin ca lement cho station, nh station c th qun l c lement. Chnh xc hn l application chy trn station v agent chy trn element mi l 2 tin trnh SNMP trc tip lin h vi nhau.

1.2.5. Cc c ch bo mt SNMP.

Mt SNMP management station c th qun l/gim st nhiu SNMP element, thng qua hot ng gi request v nhn trap. Tuy nhin mt SNMP element c th c cu hnh ch cho php cc SNMP management station no c php qun l/gim st mnh. Cc c ch bo mt n gin ny gm c: community string, view v SNMP access control list.

Community string: Community string l mt chui k t c ci t ging nhau trn c SNMP manager v SNMP agent, ng vai tr nh mt khu gia 2 bn khi trao i d liu. Community string c 3 loi: Read-community, Write-Community v Trap-Community. Khi manager gi GetRequest, GetNextRequest n agent th trong bn tin gi i c cha Read-Community. Khi agent nhn c bn tin request th n s so snh Read-community do manager gi v Read-community m n c ci t. Nu 2 chui ny ging nhau, agent s tr li; nu 2 chui ny khc nhau, agent s khng tr li.

View: Khi manager c read-community th n c th c ton b OID ca agent. Tuy nhin agent c th quy nh ch cho php c mt s OID c lin quan nhau, tc l ch c c mt phn ca MIB. Tp con ca MIB ny gi l view, trn agent c th nh ngha nhiu view.

SNMP access control list: SNMP ACL l mt danh sch cc a ch IP c php qun l/gim st agent, n ch p dng ring cho giao thc SNMP v c ci trn agent. Nu mt manager c IP khng c php trong ACL gi request th agent s khng x l, d request c community string l ng. a s cc thit b tng thch SNMP u cho php thit lp SNMP ACL.

CHNG 2: TRIN KHAI QUN L MNG VI PHN MM CACTI2.1. GII THIU V CACTI.

Cung vi s phat trin cua cac doanh nghip la s gia tng khng ngng cua cac thit bi phn cng mang, nh: may tinh ca nhn, may chu, thit bi inh tuyn, Switch, Hub va cac dich vu mang nh truyn file FTP, VPN, MAIL.. cung vi s oi hoi ln hn v bng thng mang. Nhu cu v mt h thng quan l mang ngay cang tr nn cn thit. Quan ly mang co th xem nh quan ly tt ca cac tai nguyn trong mang nhm duy tri va am bao s n inh cua toan b h thng mang, am bao an toan thng tin trn mang va m rng mang. Hin nay co rt nhiu phn mm quan ly h thng tai nguyn mang s dung thit bi phn cng t tin. Tuy nhin mt s phn mm ngun m cung ap ng mt cach toan din vi nhiu tinh nng linh hoat vt tri. Vi phn mm CACTI co kha nng b sung nhiu chng rinh plugins giup giai quyt c toan b nhng kho khn cua doanh nghip trong vic quan ly tai nguyn, cho phep quan ly s c, quan ly topo mang va cu hinh thit bi mang. Tao nn mt h thng mang chu ng. 2.2. M HNH TRIN KHAI.

M hnh gm c 1 Server Cacti ci t h iu hnh Centos, 3 PC ci t h windows, 1 Router kt ni ra internet v mng LAN, nhim v ca Server Cacti s thc hin chc nng quan ly thit bi va cac thng s trong mang trn h thng.

2.3. CI T CACTI.

Ci t cc gi cn thit trc khi ci t Cacti

Snmp-mysql, net-snmp, php-snmp, mysql-server, php-mysql, php, phpmyadmin.

S dng lnh: yum install

Ci t Cacti: Download gi cacti version mi nht ci t ti a ch http://www.cacti.net/index.php .Hoc ci trc tip bng lnh: yum install cacti.

Cu hinh thng s cho mysql thc hin lu tr c s d liu cho cacti.

Sau khi cai t xong tin hanh ng nhp vao giao din quan ly cua cacti.

2.4. CU HNH CACTI.Giao din chinh cua chng trinh.

2.4.1. Thm Thit bi quan ly.

Sau khi ng nhp thanh cng vao h thng chung ta thc hin mt s thao tac cu hinh c ban nh: Create devices for network, create graphs for your new devices, view your new graphs. thm mi mt thit bi thc hin quan ly

Chon add cu hinh thng tin thit bi thm vao quan ly.

Chung ta tin hanh in nhng thng tin c ban v thit bi.

Description: tn cn th hin cua host.

Hostname: ia chi IP hoc hostname cua may tram.

Host template: co th chon none hoc template co sn.

Downed device detection: phng phap c cacti s dung ly thng tin SNMP.

SNMP version: phin ban s dung cua SNMP trn host.

SNMP community: c cai t trn SNMP service cua host.

2.4.2. Tao graphs quan ly theo s .

La chon nhng data cn monitor va add vao danh sach, sau o save hoan tt. Sau khi tao xong new device chung ta chon create graphs for this host tao graphic cho nhng data thu thp c cua device nay, chung ta chi nn chon nhng d liu thng s thit bi nao ma chung ta cn quan tm tao graphic.

2.4.3. Quan ly c ban h thng.

Tuy thuc vao tng thit bi chung ta s dung nhng templates khac nhau co th download templace tai http://forums.cacti.net/about15067.html.Thm xong thit bi tin hanh xy dng s hinh cy hin thi tt ca cac d liu thu thp h thng quan ly d dang.

Chung ta co th import cac templace mi quan ly thit bi di dang cac biu c d dang hn.Tuy thuc vao mi thit bi va dich vu chung ta mun quan ly s co mt templates thich hp giup ngi quan tri d dang hn.

Nhng thit bi c quan ly rt chi tit v cac thng s nh: Memory, CPU, proceses

T nhng thng tin cu hinh kt hp vi templace chung ta co th quan sat h thng di dang nhng s .

Co th xem lai nhng thng tin theo ngay giup ngi quan tri nm vng tinh hinh h thng cua minh.

Chuyn sang tab graphs quan ly theo s co th la chon ngay, thang. Cu hinh ngng canh bao cho h thng

Chung ta co th add thm nhng ngng mi tuy thuc theo yu cu cua h thng. Thng thng se co mc inh mt s ngng cn thit trc.

.

Thit lp c s mang cua h thng giup quan sat thit bi c toan din hn.

KT LUN

ng trc s pht trin nhanh mnh ca nn cng ngh thng tin th gii ni chung cng nh nn cng ngh thng tin Vit Nam ni ring th h thng mng pht trin ngy cnh mnh, c th ni mt h thng mng l rt quan trng cho ngnh Cng ngh thng tin. Vi vic phi qun l c mt h thng mng tht s l rt kh khn i vi nhiu ngi, vic pht trin v qun l h thng mng ton cu rt ph hp vi nhu cu ngi dng.

Trong phm vi n mn hc qun l h thng mng, nhm chng em c nhn n tm hiu v giao thc SNMP v qun l h thng mng vi Cacti, trong qu trnh nghin cu ngoi mt s thun li nh rt nhiu ti liu trn mng s ch bo nhit tnh ca thy gio b mn, cch lm vic nhm hiu qu vi s nhit tnh ca cc thnh vin trong nhm ... th vn tn ti mt s kh khn nh phi trin khai th trn h iu hnh centos v nhiu ngun ti liu khng chnh thng, hn ch v kh nng t nghin cu ca mi thnh vin ..... tuy vy trong qu trnh thc hin nhm cng tm hiu c tng quan v giao thc SNMP v cch trin khai qun l h thng mng vi cacti, kin trc, cng ngh v quan trng hn na l bc u trin khai thnh cng cch qun l h thng mng vi cacti trn h iu hnh centos.

Tuy nhin Do thi gian hn ch v trnh hiu bit ca bn thn cha nhiu nn cha th nghin cu v trin khai qun l h thng mng hon thin, n vn mang tnh cht hc hi, trao i v bt u lm quen vi thc t. Nhng qua n mn hc ny, cc thnh vin trong nhm hc hi c nhiu kinh nghim trong qu trnh lm vic theo nhm v nghin cu mt ti quan trng, ng thi cng b sung kin thc cho bn thn.Ti liu tham kho:

[1] Insertion, Evatsion and Denial of Service: Eluding Network Intrusion Detection (Thomas H.Ptacek, Timothy N.Newsham.

[2] Diep Thanh Nguyen, 04-2010, SNMP toan tp.[3] http://www.server-world.info/en/note?os=CentOS_5&p=zabbix&f=3[4] http://www.cacti.net/index.php[5] http://www.asterisk.vn/forum/viewtopic.php?f=18&t=174&p=657#p657

Hnh 1.0: M hnh qun l tp trung

Hnh 1.7: Cu trc bn tin SNMPv2

Hnh 1.1: M hnh qun l phn tn

Hnh 1.8: Bng thng tin trong trng PDU Type

Hnh 1.12: Giao tip gia management v element

Hinh 1.2 : Cac phng thc trong SNMPv1

Hinh 2.8: S quan ly hinh cy cua chng trinh

Hinh 2.7 : Tao graphs mi cho host

Hinh 1.6: cu truc PDU setrequest

Hinh 1.5 : cu truc cua get-next

Hinh 1.4: s dung Wireshark kim tra

Hinh 1.3 : Cu trc Get/GetNext/Set/Response PDU

Hnh 2.1: M hnh trin khai

Hnh 1.11 : V tr ca SNMP trong chng giao thc TCP/IP

Hinh 2.6: Danh sach monitor

Hinh 2.5: Thng tin c ban v host

Hinh 2.4: Thit lp thit bi mi

Hnh 1.10 : M hnh giao thc hot ng SNMP

Hnh 1.9: Mi quan h gia cc thnh phn SNMP

Hinh 2.3: Giao din chinh cua chng trinh

Ging vin hng dn: Ths.L T Thanh

Lp: MM02A Nhm 5

Sinh vin thc hin- V Hong Long

- Trn Th Minh Trung

BO CO N MN HC

QUAN LY H THNG MANG

ti: Tim hiu giao thc SNMP v phn mm quan ly h thng mang CACTI

Nng, 03/2011

Hinh 2.9: Import thm templates mi

Hinh 2.16: S mang h trn h thng

Hinh 2.15: Thng tin gii han cua h thng

Hinh 2.14: Thit lp ngng canh bao cho h thng

Hinh 2.10: Thng tin cua mt templates

Hinh 2.2: ng nhp vao giao din quan ly

Hinh 2.11: Thng tin quan ly cua cac thit bi trong mang

Hinh 2.13: Quan ly theo lich

Hinh 2.12: Quan ly di dang s