Why is RIP rarely used in production networks today?
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Say this first
The 15 hop limit caps the network size. A silent failure takes minutes to converge. Hop count ignores bandwidth, so a one hop path over a slow WAN beats a two hop path over 10 Gbps links. Sending the whole table every 30 seconds wastes bandwidth and CPU at scale. It has no hierarchy, so you cannot contain changes. It still shows up on small sites, some CPE and appliances, and as a simple way to exchange a few routes with a legacy device.
Go deeper
Hop count in a real path choice
Branch R1 has two ways to the data center:
- One hop over a 10 Mbps backup circuit.
- Two hops over a 1 Gbps fiber pair. RIP picks the 10 Mbps circuit because 1 hop is less than 2. Fixing that needs an offset list to add hops to the backup path, which is manual metric tuning that EIGRP and OSPF do for you.
What replaced it
| Need | Choice |
|---|---|
| Enterprise, multivendor | OSPF |
| Enterprise, all Cisco | EIGRP or OSPF |
| Service provider core | IS-IS or OSPF |
| Between organizations | BGP |
They will ask next
Where would you still accept RIP?
A small site with a few routers and one path, or one link to a device that speaks nothing else. I would keep RIP on that single link and redistribute into the main IGP at one router with a filter.
Traps
- Saying RIP cannot do VLSM. RIPv1 cannot; RIPv2 carries masks.
How did you do?Book 3.4 Routing