Lero tiwona protocol ya BGP. Sitidzayankhula kwa nthawi yayitali chifukwa chake ndi chifukwa chake amagwiritsidwa ntchito ngati ndondomeko yokhayo. Pali zambiri zambiri pankhaniyi, mwachitsanzo .
Ndiye BGP ndi chiyani? BGP ndi protocol yosinthira ndipo ndi protocol yokhayo ya EGP (External Gateway Protocol). Protocol iyi imagwiritsidwa ntchito popanga njira pa intaneti. Tiyeni tiwone momwe oyandikana nawo amamangidwira pakati pa ma router awiri a BGP.
Ganizirani zapafupi pakati pa Router1 ndi Router3. Tiyeni tiwakonze pogwiritsa ntchito malamulo awa:
router bgp 10
network 192.168.12.0
network 192.168.13.0
neighbor 192.168.13.3 remote-as 10
router bgp 10
network 192.168.13.0
network 192.168.24.0
neighbor 192.168.13.1 remote-as 10Oyandikana nawo mkati mwa dongosolo limodzi lodziyimira pawokha ndi AS 10. Pambuyo polowa zambiri pa rauta, monga Router1, rautayo imayesa kukhazikitsa ubale woyandikana ndi Router3. Chikhalidwe choyambirira pamene palibe chikuchitika chimatchedwa Zosayenera. Bgp ikangokhazikitsidwa pa Router1, iyamba kumvera doko la TCP 179 - ilowa m'boma. kugwirizana, ndipo ikayesa kutsegula gawo ndi Router3, idzalowa m'boma yogwira.
Gawoli litakhazikitsidwa pakati pa Router1 ndi Router3, Mauthenga Otsegula amasinthidwa. Uthengawu ukatumizidwa ndi Router1, derali lidzatchedwa Tsegulani Sent. Ndipo ikalandira uthenga Wotsegula kuchokera ku Router3, idzapita ku boma Tsegulani Tsimikizani. Tiyeni tiwone bwinobwino uthenga wa Open:
Uthengawu umapereka zambiri za protocol ya BGP yokha, yomwe router imagwiritsa ntchito. Posinthana mauthenga a Open, Router1 ndi Router3 amalumikizana zokhudzana ndi makonda awo. Ma parameter awa amaperekedwa:
- Version: Izi zikuphatikiza mtundu wa BGP womwe rauta ikugwiritsa ntchito. Mawonekedwe apano a BGP ndi mtundu wa 4 womwe umafotokozedwa mu RFC 4271. Ma router awiri a BGP adzayesa kukambirana ndi Baibulo logwirizana, pamene pali kusagwirizana ndiye kuti sipadzakhala gawo la BGP.
- AS wanga: izi zikuphatikiza nambala ya AS ya rauta ya BGP, ma routers adzayenera kuvomerezana ndi AS nambala(ma) ndipo imatanthawuzanso ngati adzakhala akuyendetsa iBGP kapena eBGP.
- Gwirani Nthawi: ngati BGP sichilandira ma keepalive kapena mauthenga osintha kuchokera kumbali ina kwa nthawi yogwira ntchito ndiye idzalengeza mbali inayo 'yakufa' ndipo idzagwetsa gawo la BGP. Mwachikhazikitso nthawi yogwira imayikidwa masekondi 180 pa ma routers a Cisco IOS, uthenga wa keepalive umatumizidwa masekondi 60 aliwonse. Ma router onse awiri ayenera kuvomereza nthawi yogwira kapena sipadzakhala gawo la BGP.
- BGP ID: iyi ndi ID yakomweko ya BGP rauta yomwe imasankhidwa monga momwe OSPF imachitira:
- Gwiritsani ntchito ID ya rauta yomwe idakonzedwa pamanja ndi bgp router-id command.
- Gwiritsani ntchito adilesi yapamwamba kwambiri ya IP pamawonekedwe a loopback.
- Gwiritsani ntchito adilesi yapamwamba kwambiri ya IP pamawonekedwe akuthupi.
- Zosankha Zosankha: apa mupeza zina mwazosankha za rauta ya BGP. Gawoli lawonjezedwa kuti zinthu zatsopano ziwonjezedwe ku BGP popanda kupanga mtundu watsopano.Zinthu zomwe mungapeze apa ndi:
- thandizo la MP-BGP (Multi Protocol BGP).
- kuthandizira Kutsitsimutsa Njira.
- kuthandizira manambala a 4-octet AS.
Kukhazikitsa malo oyandikana nawo, zinthu zotsatirazi ziyenera kukwaniritsidwa:
- Nambala ya mtundu. Mtundu wapano ndi 4.
- Nambala ya AS iyenera kufanana ndi zomwe mwakonza oyandikana nawo 192.168.13.3 kutali-monga 10.
- ID ya rauta iyenera kukhala yosiyana ndi yoyandikana nayo.
Ngati zina mwazomwe sizikukwaniritsa izi, rauta idzatumiza Chidziwitso uthenga wosonyeza cholakwika. Pambuyo potumiza ndi kulandira mauthenga Otsegula, ubale wapafupi umalowa m'boma YAKHALA. Pambuyo pake, ma routers amatha kusinthana zambiri zamayendedwe ndikuchita izi pogwiritsa ntchito Pezani mauthenga. Uwu ndiye uthenga Wosintha wotumizidwa ndi Router1 kupita ku Router3:
Apa mutha kuwona maukonde onenedwa ndi Router1 ndi mawonekedwe a Path, omwe ali ofanana ndi ma metric. Tikambirana za Path mwatsatanetsatane. Mauthenga a Keepalive amatumizidwanso mkati mwa gawo la TCP. Amafalitsidwa, mwachisawawa, masekondi 60 aliwonse. Iyi ndi Keepalive Timer. Ngati uthenga wa Keepalive sunalandiridwe panthawi ya Hold Timer, izi zikutanthauza kutayika kwa kulumikizana ndi mnansi. Mwachikhazikitso, ndi ofanana ndi 180 masekondi.
Chizindikiro chothandiza:
Zikuwoneka kuti taganizira momwe ma routers amatumizirana mauthenga kwa wina ndi mzake, tsopano tiyeni tiyese kumvetsetsa malingaliro a protocol ya BGP.
Kulengeza njira yopita ku tebulo la BGP, monga mu ndondomeko za IGP, lamulo la intaneti likugwiritsidwa ntchito, koma malingaliro ogwiritsira ntchito ndi osiyana. Ngati mu IGP, pambuyo pofotokoza njira mu lamulo la maukonde, IGP imayang'ana zomwe zimalumikizana ndi subnet iyi ndikuziphatikiza patebulo lake, ndiye kuti lamulo la netiweki ku BGP limayang'ana pa tebulo lolowera ndikuyang'ana. molondola zimagwirizana ndi njira yomwe ili mu lamulo la netiweki. Ngati izi zipezeka, njirazi ziziwoneka patebulo la BGP.
Yang'anani njira mu tebulo lamakono la IP la router lomwe likufanana ndendende ndi magawo a lamulo la intaneti; ngati njira ya IP ilipo, ikani NLRI yofanana pa tebulo lapafupi la BGP.
Tsopano tiyeni tikweze BGP kwa otsala onse ndikuwona momwe njirayo imasankhidwira mkati mwa AS imodzi. Pambuyo pa rauta ya BGP ilandila njira kuchokera kwa mnansi wake, imayamba kusankha njira yabwino. Apa muyenera kumvetsetsa mtundu wa oyandikana nawo omwe angakhalepo - mkati ndi kunja. Kodi rauta imamvetsetsa mwakusintha ngati mnansi wokonzedwayo ndi wamkati kapena wakunja? Ngati mu timu:
neighbor 192.168.13.3 remote-as 10 kutali-monga parameter imatanthawuza AS, yomwe imapangidwira pa router yokha mu lamulo la router bgp 10. Njira zochokera mkati mwa AS zimaonedwa kuti ndi zamkati, ndipo njira zochokera kunja kwa AS zimaonedwa kuti ndi zakunja. Ndipo kwa aliyense, malingaliro osiyanasiyana olandila ndi kutumiza ntchito. Taganizirani topology iyi:
Routa iliyonse ili ndi mawonekedwe a loopback okonzedwa ndi ip: xxxx 255.255.255.0 - pomwe x ndi nambala ya rauta. Pa Router9 tili ndi mawonekedwe a loopback ndi adilesi - 9.9.9.9 255.255.255.0. Tizilengeza kudzera pa BGP ndikuwona momwe zikufalikira. Njirayi itumizidwa ku Router8 ndi Router12. Kuchokera pa Router8, njira iyi ipita ku Router6, koma kupita ku Router5 sikhala pa tebulo lamayendedwe. Komanso pa Router12 njira iyi idzawonekera patebulo, koma pa Router11 sipadzakhalanso. Tiyeni tiyese kulingalira izi. Tiyeni tiwone zomwe data ndi magawo a Router9 amatumiza kwa oyandikana nawo, ndikuwonetsa njira iyi. Paketi ili pansipa itumizidwa kuchokera ku Router9 kupita ku Router8.
Zambiri zanjira zimakhala ndi mawonekedwe a Path.
Makhalidwe anjira amagawidwa m'magulu 4:
- Wodziwika bwino kukakamizidwa - Ma routers onse omwe akuyendetsa BGP ayenera kuzindikira izi. Ayenera kupezeka pazosintha zonse.
- Odziwika discretionary - Ma routers onse omwe akuyendetsa BGP ayenera kuzindikira izi. Atha kukhalapo pazosintha, koma kupezeka kwawo sikofunikira.
- Zosintha ngati mukufuna - sizingadziwike ndi machitidwe onse a BGP. Ngati rauta sichizindikira chikhalidwecho, imayika zosinthazo ngati pang'onopang'ono ndikuzitumiza kwa oyandikana nawo, ndikusunga mawonekedwe osadziwika.
- Zosasintha - sizingadziwike ndi machitidwe onse a BGP. Ngati rauta sazindikira chikhumbocho, ndiye kuti chikhalidwecho chimanyalanyazidwa ndikutayidwa chikaperekedwa kwa oyandikana nawo.
Zitsanzo za mawonekedwe a BGP:
- Wodziwika bwino kukakamizidwa:
- Njira ya Autonomous System
- Chotsatira-hop
- Origin
- Odziwika discretionary:
- Zokonda kwanuko
- Atomiki aggregate
- Zosintha ngati mukufuna:
- Chiwerengero
- Madera
- Zosasintha:
- Multi-exit discriminator (MED)
- ID yoyambitsa
- Mndandanda wamagulu
Pankhaniyi, pakadali pano tikhala ndi chidwi ndi Origin, Next-hop, AS Path. Popeza njirayo imadutsa pakati pa Router8 ndi Router9, ndiye kuti, mkati mwa AS imodzi, imatengedwa kuti ndi yamkati ndipo tidzatchera khutu ku Origin.
Choyambira - chikuwonetsa momwe njira yosinthira idalandilidwa. Zomwe zingatheke:
- 0 - IGP: NLRI idalandiridwa mkati mwadongosolo lodziyimira palokha;
- 1 - EGP: NLRI imaphunziridwa pogwiritsa ntchito Exterior Gateway Protocol (EGP). Predecessor to BGP, osagwiritsidwa ntchito
- 2 - Yosakwanira: NLRI idaphunziridwa mwanjira ina
Kwa ife, monga momwe tingawonere pa paketi, ndi yofanana ndi 0. Njirayi ikatumizidwa ku Router12, code iyi idzakhala ndi code 1.
Kenako, Next-hop. Chotsatira-hop chikhalidwe
- Iyi ndi adilesi ya IP ya rauta ya eBGP yomwe njira yopita ku netiweki imadutsa.
- Khalidwe limasintha pamene choyambirira chitumizidwa ku AS wina.
Pankhani ya iBGP, ndiye kuti, mkati mwa AS imodzi, Next-hop idzawonetsedwa ndi amene adaphunzira kapena kuwuza za njirayi. Kwa ife, idzakhala 192.168.89.9. Koma njira iyi ikadutsa kuchokera ku Router8 kupita ku Router6, Router8 isintha ndikuyika yakeyake. Chotsatira-hop chidzakhala 192.168.68.8. Izi zikutifikitsa ku malamulo awiri:
- Ngati rauta ipititsa patsogolo njira yopita kwa mnansi wake wamkati, sizisintha parameter Next-hop.
- Ngati rauta itumiza njira kwa mnansi wake wakunja, imasintha Next-hop kupita ku IP ya mawonekedwe omwe rautayi imadutsa.
Izi zimatipangitsa kumvetsetsa vuto loyamba - Chifukwa chake sipadzakhala njira patebulo la Router5 ndi Router11. Tiyeni tione bwinobwino. Chifukwa chake, Router6 idalandira zambiri za njira 9.9.9.0/24 ndikuwonjezera bwino patebulo lolowera:
Router6#show ip route bgp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
9.0.0.0/24 is subnetted, 1 subnets
B 9.9.9.0 [20/0] via 192.168.68.8, 00:38:25<source>
Π’Π΅ΠΏΠ΅ΡΡ Router6 ΠΏΠ΅ΡΠ΅Π΄Π°Π» ΠΌΠ°ΡΡΡΡΡ Router5 ΠΈ ΠΏΠ΅ΡΠ²ΠΎΠΌΡ ΠΏΡΠ°Π²ΠΈΠ»Ρ Next-hop Π½Π΅ ΠΈΠ·ΠΌΠ΅Π½ΠΈΠ». Π’ΠΎ Π΅ΡΡΡ, Router5 Π΄ΠΎΠ»ΠΆΠ΅Π½ Π΄ΠΎΠ±Π°Π²ΠΈΡΡ <b>9.9.9.0 [20/0] via 192.168.68.8</b> , Π½ΠΎ Ρ Π½Π΅Π³ΠΎ Π½Π΅Ρ ΠΌΠ°ΡΡΡΡΡΠ° Π΄ΠΎ 192.168.68.8 ΠΈ ΠΏΠΎΡΡΠΎΠΌΡ Π΄Π°Π½Π½ΡΠΉ ΠΌΠ°ΡΡΡΡΡ Π΄ΠΎΠ±Π°Π²Π»Π΅Π½ Π½Π΅ Π±ΡΠ΄Π΅Ρ, Ρ
ΠΎΡΡ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΡ ΠΎ Π΄Π°Π½Π½ΠΎΠΌ ΠΌΠ°ΡΡΡΡΡΠ΅ Π±ΡΠ΄Π΅Ρ Ρ
ΡΠ°Π½ΠΈΡΡΡΡ Π² ΡΠ°Π±Π»ΠΈΡΠ΅ BGP:
<source><b>Router5#show ip bgp
BGP table version is 1, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
* i 9.9.9.0/24 192.168.68.8 0 100 0 45 i</b>Zomwezo zidzachitika pakati pa Router11-Router12. Kuti mupewe izi, muyenera kukonza Router6 kapena Router12, podutsa njira yopita kwa oyandikana nawo amkati, kuti mulowe m'malo mwa adilesi yawo ya IP monga Next-hop. Izi zimachitika pogwiritsa ntchito lamulo:
neighbor 192.168.56.5 next-hop-selfPambuyo pa lamulo ili, Router6 idzatumiza uthenga Wosintha, pomwe ip ya mawonekedwe a Gi0 / 0 Router6 idzafotokozedwa ngati Next-hop kwa maulendo - 192.168.56.6, pambuyo pake njirayi idzaphatikizidwa kale patebulo lolowera.
Tiyeni tipite patsogolo ndikuwona ngati njira iyi ikuwoneka pa Router7 ndi Router10. Sizikhala patebulo lolowera ndipo titha kuganiza kuti vuto ndi lofanana ndi loyamba lomwe lili ndi Next-hop parameter, koma ngati tiyang'ana zotsatira za ip bgp command, tiwona kuti Njira sinalandilidwe kumeneko ngakhale ndi Next-hop yolakwika, zomwe zikutanthauza kuti njirayo sinapatsidwe nkomwe. Ndipo izi zidzatifikitsa ku kukhalapo kwa lamulo lina:
Njira zolandilidwa kuchokera kwa oyandikana nawo amkati sizimafalitsidwa kwa oyandikana nawo amkati.
Popeza Router5 idalandira njira kuchokera ku Router6, sipatsirana kwa oyandikana nawo ena amkati. Kuti kusamutsa kuchitike, muyenera kukonza ntchito , kapena sinthani maulalo oyandikana nawo (Full Mesh), ndiye kuti, Router5-7 aliyense adzakhala woyandikana nawo aliyense. Pankhaniyi, tigwiritsa ntchito Route Reflector. Pa Router5 muyenera kugwiritsa ntchito lamulo ili:
neighbor 192.168.57.7 route-reflector-clientRoute-Reflector amasintha machitidwe a BGP podutsa njira yopita kwa mnansi wamkati. Ngati woyandikana naye wamkati atchulidwa kuti njira-reflector-kasitomala, ndiye njira zamkati zidzalengezedwa kwa makasitomalawa.
Njirayo sinawonekere pa Router7? Musaiwale za Next-hop mwina. Pambuyo pakusintha uku, njirayo iyeneranso kupita ku Router7, koma izi sizichitika. Izi zikutifikitsa ku lamulo lina:
Lamulo lotsatira-hop limagwira ntchito panjira Zakunja. Kwa njira zamkati, mawonekedwe a hop yotsatira samasinthidwa.
Ndipo timapeza nthawi yomwe kuli kofunikira kupanga malo pogwiritsa ntchito static routing kapena IGP protocol kuti tidziwitse ma routers za misewu yonse mkati mwa AS. Tiyeni tilembetse njira zokhazikika pa Router6 ndi Router7 ndipo pambuyo pake tipeza njira yomwe tikufuna patebulo la rauta. Mu AS 678, tidzachita mosiyana pang'ono - tidzalembetsa mayendedwe okhazikika a 192.168.112.0/24 pa Router10 ndi 192.168.110.0/24 pa Router12. Kenako, tikhazikitsa ubale wapafupi pakati pa Router10 ndi Router12. Tidzakonzanso Router12 kuti itumize hop yake yotsatira ku Router10:
neighbor 192.168.110.10 next-hop-selfZotsatira zake zikhala kuti Router10 ilandila njira 9.9.9.0/24, ilandila kuchokera ku Router7 ndi Router12. Tiyeni tiwone chomwe Router10 imapanga:
Router10#show ip bgp
BGP table version is 3, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*>i 9.9.9.0/24 192.168.112.12 0 100 0 45 i
192.168.107.7 0 123 45 i
Monga tikuonera, njira ziwiri ndi muvi (>) zikutanthauza kuti njira yodutsa 192.168.112.12 yasankhidwa.
Tiyeni tiwone momwe kusankha njira kumagwirira ntchito:
- Gawo loyamba mukalandira njira ndikuwunika kupezeka kwa Next-hop yake. Ichi ndichifukwa chake, titalandira njira pa Router5 popanda kukhazikitsa Next-hop-self, njira iyi sinakonzedwenso.
- Kenako pakubwera Weight parameter. Parameter iyi si Path Attribute (PA) ndipo sichimatumizidwa mu mauthenga a BGP. Zimakonzedwa kwanuko pa rauta iliyonse ndipo zimangogwiritsidwa ntchito kuwongolera kusankha njira pa rauta yokha. Tiyeni tione chitsanzo. Pamwambapa mutha kuwona kuti Router10 yasankha njira ya 9.9.9.0/24 kudzera pa Router12 (192.168.112.12). Kuti musinthe gawo la Wieght, mutha kugwiritsa ntchito mapu-njira kukhazikitsa njira zinazake, kapena perekani zolemetsa kwa mnansi wake pogwiritsa ntchito lamulo:
neighbor 192.168.107.7 weight 200Tsopano njira zonse zochokera kwa mnansi uyu zidzakhala ndi kulemera kwake. Tiyeni tiwone momwe kusankha kwanjira kumasinthira pambuyo pakusintha uku:
Router10#show bgp *Mar 2 11:58:13.956: %SYS-5-CONFIG_I: Configured from console by console BGP table version is 2, local router ID is 6.6.6.6 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 9.9.9.0/24 192.168.107.7 200 123 45 i * i 192.168.112.12 0 100 0 45 iMonga mukuonera, njira yodutsa pa Router7 yasankhidwa, koma izi sizikhala ndi zotsatira pa ma router ena.
- Pamalo achitatu tili ndi Local Preference. Parameter iyi ndi yodziwika bwino ya discretionary, zomwe zikutanthauza kuti kupezeka kwake ndikosankha. Izi ndizovomerezeka mkati mwa AS imodzi ndipo zimakhudza kusankha njira kwa oyandikana nawo amkati. Ichi ndichifukwa chake amafalitsidwa kokha mu Mauthenga Osintha omwe amaperekedwa kwa mnansi wamkati. Palibe mu Mauthenga a Update kwa oyandikana nawo akunja. Chifukwa chake, idasankhidwa kukhala yodziwika bwino ya discretionary. Tiyeni tiyese kugwiritsa ntchito pa Router5. Pa Router5 tiyenera kukhala ndi njira ziwiri za 9.9.9.0/24 - imodzi kudzera pa Router6 ndi yachiwiri kudzera pa Router7.
Tikuwona:
Router5#show bgp BGP table version is 2, local router ID is 5.5.5.5 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.56.6 0 100 0 45 iKoma monga tikuwona njira imodzi kudutsa Router6. Kodi njira yodutsa pa Router7 ili kuti? Mwina Router7 alibenso? Tiyeni tiwone:
Router#show bgp BGP table version is 10, local router ID is 7.7.7.7 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.56.6 0 100 0 45 i 192.168.107.10 0 678 45 iChodabwitsa, zonse zikuwoneka bwino. Chifukwa chiyani sichikuperekedwa ku Router5? Chowonadi ndi chakuti BGP ili ndi lamulo:
Router imatumiza njira zokhazo zomwe imagwiritsa ntchito.
Router7 imagwiritsa ntchito njira yodutsa pa Router5, kotero njira yodutsa pa Router10 sipatsirana. Tiyeni tibwerere ku Local Preference. Tiyeni tiyike Local Preference pa Router7 ndikuwona momwe Router5 imachitira izi:
route-map BGP permit 10 match ip address 10 set local-preference 250 access-list 10 permit any router bgp 123 neighbor 192.168.107.10 route-map BGP in</b>Chifukwa chake, tidapanga mapu amayendedwe omwe ali ndi njira zonse ndipo tidauza Router7 kuti musinthe zokonda za Local Preference kukhala 250 zikalandiridwa, zokhazikika ndi 100. Tiyeni tiwone zomwe zidachitika pa Router5:
Router5#show bgp BGP table version is 8, local router ID is 5.5.5.5 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.57.7 0 250 0 678 45 iMonga tikuonera tsopano Router5 imakonda njira yodutsa Router7. Chithunzi chomwechi chidzakhala pa Router6, ngakhale ndizopindulitsa kwambiri kuti asankhe njira kudzera pa Router8. Timawonjezeranso kuti kusintha parameter iyi kumafuna kuyambiranso kwapafupi kuti kusinthaku kuchitike. Werengani . Tasankha Local Preference. Tiyeni tipite ku gawo lotsatira.
- Kukonda njira yokhala ndi Next-hop parameter 0.0.0.0, ndiko kuti, njira zakomweko kapena zophatikiza. Njirazi zimangoperekedwa kwa Weight parameter yofanana ndi pazipita-32678-atalowa lamulo lamaneti:
Router#show bgp BGP table version is 2, local router ID is 9.9.9.9 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 9.9.9.0/24 0.0.0.0 0 32768 i - Njira yayifupi kwambiri yodutsa AS. Gawo lalifupi kwambiri la AS_Path lasankhidwa. Njira yocheperako ikadutsa, imakhala yabwinoko. Ganizirani njira yopita ku 9.9.9.0/24 pa Router10:
Router10#show bgp BGP table version is 2, local router ID is 6.6.6.6 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 9.9.9.0/24 192.168.107.7 0 123 45 i *>i 192.168.112.12 0 100 0 45 iMonga mukuwonera, Router10 idasankha njira kudzera pa 192.168.112.12 chifukwa panjira iyi AS_Path parameter ili ndi 45 yokha, ndipo mwanjira ina 123 ndi 45. Mwachidziwitso momveka bwino.
- Chotsatira chotsatira ndi Origin. IGP (njira anapezerapo ntchito BGP) ndi bwino kuposa EGP (njira anapezerapo ntchito BGP a kuloΕ΅edwa m'malo, salinso ntchito), ndi EGP ndi bwino kuposa chosakwanira? (zopezedwa ndi njira ina, mwachitsanzo pogawanso).
- Chotsatira chotsatira ndi MED. Tidali ndi Wieght yomwe inkangogwira ntchito kwanuko pa rauta. Panali Local Preference, yomwe inkangogwira ntchito mkati mwa dongosolo limodzi lodzilamulira. Monga momwe mungaganizire, MED ndi gawo lomwe lidzafalikira pakati pa machitidwe odziyimira pawokha. Zabwino kwambiri za parameter iyi.
Sipadzagwiritsidwanso ntchito, koma ngati njira ziwiri zili ndi mawonekedwe ofanana, ndiye kuti malamulo otsatirawa amagwiritsidwa ntchito:
- Sankhani njira yodutsa mnansi wapafupi wa IGP.
- Sankhani njira yakale kwambiri yanjira ya eBGP.
- Sankhani njira yodutsa mnansi ndi ID yaying'ono ya rauta ya BGP.
- Sankhani njira kudzera mwa mnansi wokhala ndi adilesi yotsika kwambiri ya IP.
Tsopano tiyeni tione nkhani ya BGP convergence.
Tiyeni tiwone zomwe zingachitike ngati Router6 itaya njira 9.9.9.0/24 kudzera pa Router9. Tiyeni tiyimitse mawonekedwe a Gi0/1 a Router6, omwe amvetsetsa nthawi yomweyo kuti gawo la BGP ndi Router8 lathetsedwa ndipo woyandikana nawo wasowa, zomwe zikutanthauza kuti njira yomwe idalandilidwa siili yolondola. Router6 nthawi yomweyo imatumiza Mauthenga Osintha, pomwe imawonetsa netiweki 9.9.9.0/24 m'gawo la Njira Zochotsa. Router5 ikangolandira uthenga wotere, imatumiza ku Router7. Koma popeza Router7 ili ndi njira yodutsa Router10, iyankha nthawi yomweyo ndi Kusintha ndi njira yatsopano. Ngati sizingatheke kuzindikira kugwa kwa mnansi kutengera momwe mawonekedwe ake alili, ndiye kuti muyenera kudikirira kuti Hold Timer iwotche.
Confederation.
Ngati mukukumbukira, tidakambirana kuti nthawi zambiri muyenera kugwiritsa ntchito topology yolumikizidwa kwathunthu. Ndi ma routers ambiri m'modzi AS izi zingayambitse mavuto akulu, kuti mupewe izi muyenera kugwiritsa ntchito chitaganya. Mmodzi wa AS amagawidwa m'magulu angapo a AS, omwe amawalola kuti azigwira ntchito popanda kufunikira kwa topology yolumikizidwa kwathunthu.
Nawu ulalo wa izi ndi Kusintha kwa GNS3.
Mwachitsanzo, ndi topology iyi tiyenera kulumikiza ma routers onse mu AS 2345 wina ndi mzake, koma pogwiritsa ntchito Confederation, tikhoza kukhazikitsa maubwenzi oyandikana okha pakati pa ma routers ogwirizana. Tiyeni tikambirane zimenezi mwatsatanetsatane. Tikadakhala ndi AS 2345, ndiye laForge atalandira ulendo kuchokera Picard angawuze kwa ma routers Deta ΠΈ Worf, koma sanauze rauta za izo Crusher . Komanso njira zogawidwa ndi rauta yokha laForge, sakanasamutsidwa Crusher ngakhale Worf-o, pa Deta.
Muyenera kukonza Route-Reflector kapena ubale wolumikizidwa kwathunthu. Pogawa AS 2345 imodzi mu 4 sub-AS (2,3,4,5) pa router iliyonse, timathera ndi malingaliro osiyana ogwiritsira ntchito. Chilichonse chikufotokozedwa bwino .
Zotsatira:
- CCIE Routing and Switching v5.0 Official Cert Guide, Volume 2, Fifth Edition, Narbik Kocharians, Terry Vinson.
- webusaiti
- webusaiti .
Source: www.habr.com