🎤 CCNP ENARSI 300-410 — Interview Q&A

❓ EIGRP DUAL کیسے کام کرتا ہے؟EIGRP DUAL kaise kaam karta hai?How does EIGRP DUAL work?

DUAL (Diffusing Update Algorithm) successor اور feasible successor راستے نکالتا ہے۔ Feasible successor feasibility condition پوری کرتا ہے (اس کا advertised distance میرے feasible distance سے کم)، اس لیے بغیر active ہوئے فوراً سنبھال لیتا ہے۔DUAL (Diffusing Update Algorithm) successor aur feasible successor raste nikalta hai. Feasible successor feasibility condition poori karta hai (uska advertised distance mere feasible distance se kam), is liye baghair active hue foran sambhal leta hai.DUAL (Diffusing Update Algorithm) computes successor and feasible successor routes. A feasible successor meets the feasibility condition (its advertised distance is less than my feasible distance), so it can take over instantly without going active.

❓ Stub، totally stubby اور NSSA areas کا موازنہ کریں۔Stub, totally stubby aur NSSA areas ka mawazna karein.Compare stub, totally stubby, and NSSA areas.

Stub Type 5 روکتا ہے (default route ملتا ہے)۔ Totally stubby Type 3 اور 5 روکتا ہے۔ NSSA Type 7 کی اجازت دیتا ہے تاکہ اندر ASBR ہو سکے۔Stub Type 5 rokta hai (default route milta hai). Totally stubby Type 3 aur 5 rokta hai. NSSA Type 7 ki ijazat deta hai taake andar ASBR ho sake.Stub blocks Type 5 (gets default route). Totally stubby blocks Types 3 and 5. NSSA allows Type 7 so an ASBR can exist inside the area.

❓ Mutual redistribution میں loops کیسے روکتے ہیں؟Mutual redistribution mein loops kaise rokte hain?How do you prevent loops in mutual redistribution?

Route tags: ایک سمت میں راستوں پر tag لگائیں اور واپسی کے route-map میں اس tag کو deny کریں۔ ساتھ ہی صحیح seed metrics، subnets keyword اور مناسب AD استعمال کریں۔Route tags: ek simt mein raston par tag lagayein aur wapsi ke route-map mein is tag ko deny karein. Sath hi sahi seed metrics, subnets keyword aur munasib AD istemal karein.Route tags: tag routes in one direction and deny that tag in the reverse route-map. Also use correct seed metrics, the subnets keyword, and sane AD.

❓ BGP best-path selection سمجھائیں۔BGP best-path selection samjhayein.Walk me through BGP best-path selection.

Weight → Local-preference → locally originated → چھوٹا AS-path → کم origin → کم MED → eBGP over iBGP → کم IGP metric → کم router-ID۔Weight → Local-preference → locally originated → chhota AS-path → kam origin → kam MED → eBGP over iBGP → kam IGP metric → kam router-ID.Weight → Local-preference → locally originated → shortest AS-path → lowest origin → lowest MED → eBGP over iBGP → lowest IGP metric → lowest router-ID.

❓ MPLS L3VPN customer راستوں کو الگ کیسے رکھتا ہے؟MPLS L3VPN customer raston ko alag kaise rakhta hai?How does an MPLS L3VPN keep customer routes separate?

ایک راؤٹر ہر customer کے لیے الگ routing tables رکھتا ہے (VRF)۔ RD overlapping prefixes کو MP-BGP میں منفرد بناتا ہے؛ RT (extended community) طے کرتا ہے کہ کون سی VRF کون سا route import کرے۔Ek router har customer ke liye alag routing tables rakhta hai (VRF). RD overlapping prefixes ko MP-BGP mein munfarid banata hai; RT (extended community) tay karta hai ke kaun si VRF kaun sa route import kare.One router holds separate routing tables per customer (VRF). RD makes overlapping prefixes unique in MP-BGP; RT (extended community) decides which VRF imports which route.

❓ DMVPN کے تینوں phases سمجھائیں۔DMVPN ke teenon phases samjhayein.Explain the three DMVPN phases.

Phase 1: spoke-to-spoke hub سے جاتا ہے۔ Phase 2: spokes direct tunnel بناتے ہیں (routing سے subnets معلوم)۔ Phase 3: hub NHRP redirect بھیجتا ہے اور spokes shortcut switching کرتے ہیں — تجویز کردہ ڈیزائن۔Phase 1: spoke-to-spoke hub se jata hai. Phase 2: spokes direct tunnel banate hain (routing se subnets maloom). Phase 3: hub NHRP redirect bhejta hai aur spokes shortcut switching karte hain — tajweez karda design.Phase 1: spoke-to-spoke goes via the hub. Phase 2: spokes build direct tunnels (subnets known via routing). Phase 3: hub sends NHRP redirects and spokes use shortcut switching — the recommended design.

❓ PBR vs عام routing — PBR کب استعمال کریں گے؟PBR vs aam routing — PBR kab istemal karenge?PBR vs normal routing — when would you use PBR?

PBR source، protocol یا port پر forwarding فیصلہ کرتی ہے اور routing table کو override کرتی ہے۔ عام routing destination-based RIB lookup ہے۔ PBR policy exceptions کے لیے ہے؛ RIB default رہتی ہے۔PBR source, protocol ya port par forwarding faisla karti hai aur routing table ko override karti hai. Aam routing destination-based RIB lookup hai. PBR policy exceptions ke liye hai; RIB default rehti hai.PBR makes forwarding decisions on source, protocol, or port and overrides the routing table. Normal routing is destination-based RIB lookup. PBR is for policy exceptions; the RIB stays the default.

❓ Routing مسئلے کے لیے اپنا troubleshooting طریقہ بتائیں۔Routing masle ke liye apna troubleshooting tareeqa batayein.Describe your troubleshooting approach for a routing issue.

مسئلے کی تعریف کریں، Layer 1/2 چیک کریں، routing table دیکھیں، protocol-specific checks چلائیں، ضرورت پر محدود debug، حل کی تصدیق کریں اور دستاویز کریں۔Masle ki tareef karein, Layer 1/2 check karein, routing table dekhein, protocol-specific checks chalayein, zaroorat par mehdood debug, hal ki tasdeeq karein aur dastavez karein.Define the problem, check Layer 1/2, check the routing table, run protocol-specific checks, use scoped debug only if needed, verify the fix, and document it.