RIPv1 vs. RIPv2
RIP is a distance-vector routing protocol, that’s limited by it’s hop count. The maximum number of hops allowed for RIP is 15. This hop limit however also limits the size of networks that RIP can support. RIP is well suited as an IGP in that it has no concept of Autonomous Systems. RIP considers a hop count of 16 as an infinite distance and inaccessible, inoperable, or otherwise undesirable route in the selection process. When I consider IGP routing protocols RIP is the first one that comes to mind simply due to its simplicity.
RIPv1
- IPv4
- Classful
- Updates do not carry subnet information
- No support for variable length subnet masks or VLSM
- Broadcast it’s entire routing table
- Distance Victor
- Count to infinity metric = 16
- UDP 520
- Broadcast 255.255.255.255
- RFC – 1058
RIPv2
- IPv4
- Classless
- Control Plan security supports both clear text and MD5 authentication
- Supports Redistribution
- Supports Route Tagging
- Distance Victor
- Count to infinity metric = 16
- UDP 520
- Link Local Multicast 224.0.0.9
- RFC – 2453
RIPng
- IPv6
- Classless – The concept of classes such as A, B, C, D don’t exist within IPv6
- Control Plan Security supports both clear text and MD5 authentication
- Supports Redistribution
- Supports Route Tagging
- Distance Victor
- Count to infinity metric = 16
- UDP 521
- Link Local Multicast FF02::9
- RFC – 2080
Split Horizon vs. Poison Reverse
- SH: Doesn’t advertise routes back out the interface from which they were learned
- PR: Advertise the route or routes back out the same interface, but with an infinite metric of 16
The RIP Database
Much like EIGRP, and OSPF the RIP protocol utilizes a separate table or database to store routes received from other RIP neighbors. The RIP database is used help determine which routes are installed or injected in the routing table along with generating outbound RIP updates. RIP summary routes will appear only in the RIP database, and not in the routing table.
Default Timers and Administrative Distance
- Update: 30
- Invalid: 180
- Hold Down: 180
- Flush: 240
- AD: 120
Common Routing Decision
- Prefer the route with the longest Prefix Length
- Prefer the route with the lowest Metric
- Prefer the route with the lowest Administrative Distance
RIP is simply a Distance / Vector routing protocol nothing more nothing less. It computes the best route or path to a destination using distance ( Hop Count ) and a vector ( Next Hop) to derive its routes. For instance, all the routers in the network in Figure 1 are running Routing Information Protocol (RIP). Router Two chooses the path to Network A by examining the hop count through each available path.
