---
title: "Routing criteria; RIP, OSPF, BGP, IGRP, EIGRP"
subject: "Computer Networks and Security"
chapter: 4
key: "semester_7/computer_networks_and_security:routing-criteria-protocols"
source: https://www.bctengineer.com/q/semester_7/computer_networks_and_security/routing-criteria-protocols
site: BCT Engineering
---

# Routing criteria; RIP, OSPF, BGP, IGRP, EIGRP

Computer Networks and Security · Chapter 4: Network Layer

- Asked in: 2074 Chaitra, 2+6 marks
- Video: [RIP vs OSPF vs EIGRP: Which Routing Protocol Wins?](https://www.youtube.com/watch?v=j7OPw0WiOCs) — IT Boost by Formip
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/computer_networks_and_security/routing-criteria-protocols
- Whole chapter: https://www.bctengineer.com/md/semester_7/computer_networks_and_security/chapter-4

## Question

Mention the criteria for good routing. Explain RIP, OSPF, BGP, IGRP and EIGRP.

## Short answer

Good routing must be correct, robust, stable, fair, adaptive, and efficient. RIP uses hop count (max 15) with 30s updates. OSPF uses Dijkstra with bandwidth cost and areas for fast convergence. BGP is a path-vector protocol for inter-AS routing with policy control. IGRP uses composite metric; EIGRP uses DUAL for fast, loop-free convergence with VLSM support.

## Answer

#### Criteria for good routing
A good routing algorithm should be:
1. **Correct and simple:** it delivers packets to the destination with low overhead.
2. **Robust:** works despite hardware or topology failures.
3. **Stable:** converges to a steady state and avoids loops.
4. **Fair and optimal:** shortest or least-cost path by hop count, delay, bandwidth or cost, and fair to all users.
5. **Adaptive and scalable:** adjusts to traffic and topology change, and works for large networks.
6. **Efficient:** low use of CPU, memory and bandwidth.

#### Routing protocols
| Protocol | Type | Key points |
|---|---|---|
| RIP | Interior, distance vector | Metric hop count (max 15), updates every 30 s, UDP 520, simple, slow convergence |
| OSPF | Interior, link state | Uses Dijkstra (SPF), cost metric based on bandwidth, areas (area 0 backbone), fast convergence, multicast hello, IP protocol 89 |
| BGP | Exterior, path vector | Between autonomous systems, uses path attributes and policy, runs over TCP 179, backbone of the Internet |
| IGRP | Interior, distance vector (Cisco) | Composite metric of bandwidth, delay, reliability, load; max 255 hops; updates every 90 s; replaced by EIGRP |
| EIGRP | Interior, advanced distance vector (Cisco) | DUAL algorithm, fast convergence, partial triggered updates, composite metric, supports VLSM, loop free, neighbour tables |

**Interior vs exterior:** RIP, OSPF, IGRP and EIGRP route inside one AS (intra-domain), while BGP routes between ASs (inter-domain).

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which is an exterior protocol running on TCP 179?
   A. RIP
   B. OSPF
   C. BGP
   D. EIGRP
   Answer: C. BGP is path vector between autonomous systems. (Key point: BGP)

2. Which statement fits OSPF?
   A. Distance vector, hop count
   B. Link state with Dijkstra and area 0 backbone
   C. Path vector
   D. Cisco-only
   Answer: B. OSPF is link state using SPF and areas. (Key point: OSPF)

3. EIGRP uses which algorithm?
   A. Bellman-Ford only
   B. DUAL
   C. Dijkstra
   D. Path attributes
   Answer: B. EIGRP is advanced distance vector using DUAL, loop-free. (Key point: EIGRP)

4. Which is true of IGRP?
   A. Max 15 hops, 30 s
   B. Cisco, composite metric, max 255 hops, 90 s updates
   C. Exterior
   D. Uses TCP
   Answer: B. IGRP was replaced by EIGRP. (Key point: IGRP)

## Related in Computer Networks and Security

- [Routing Information Protocol (RIP)](https://www.bctengineer.com/question.md?key=semester_7%2Fcomputer_networks_and_security%3Arip-protocol) — Computer Networks and Security, chapter 4

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