Tech Corner

Configure and Route Efficiently with the Routing Information Protocol

Flow is important whether it comes to cash flow, traffic flow, or even data flow. To increase network productivity, finding the most efficient way to route data is key to remaining effective in the network. What protocols do you use to efficiently route data within your network? If you have a small to medium-sized network, you may find yourself using Routing Information Protocols (RIP). Though when looking more into large enterprise networks, RIP doesn't quite make the cut so the transition from a distance-vector protocol to a link-state protocol (OSPF) may be necessary. Today, we will look at the benefits of RIP, a few basic RIP configurations on an ASR router, and a sneak-peek into OSPF routing.

A Quick Look at RIP

The RIP is a classic distance-vector Interior Gateway Protocol designed to exchange information within an autonomous system of a small network. Its primary functions are to determine the most efficient way to route data within a network and prevent routing loops.

By using distance-vector routing, it calculates the best path based on the direction and distance between routers. RIP prevents routing loops by limiting the number of 'hops' between the source and destination. Both the distance-vector routing and routing loop prevention use packets to forward information to appropriate routers. The distance vector calculates the distance and direction of the packet while the routing loop prevention uses hops to record each time a packet is forwarded from one router to another.

As you may know, RIP is not the only protocol to consider. Check out how RIP compares to other protocols and how you can leverage them in your network. Click here to view the comparison.

RIP Versions

RIP Version 1 (RIPv1) is a distance-vector protocol that is considered the easiest routing protocol to implement as compared to OSPF. As a Classful Routing Protocol, RIPv1 allows only contiguous blocks of hosts, subnets, or networks to be represented by a single route, severely limiting its usefulness. 

RIP Version 2 (RIPv2) is a Classless Routing Protocol because it sends information of subnet mask in its routing update, unlike Version 1. This version allows more information carried in RIP update packets, such as support for:

  • Route summarizing
  • Classless inter-domain routing 
  • Variable-length subnet masks 
  • Autonomous systems and the use of redistribution
  • Multicast address for RIP advertisements

To highlight the autonomous systems and use of redistribution, redistribution is a process that allows exchanging routing information between different routing processes or from static information to the routing process. RIPv2 multicasts the entire routing table to all adjacent routers at the address, whereas RIPv1 uses 

RIPng (RIP next generation) is an extension of RIPv2. This next-generation Internet Protocol supports IPv6 using IPsec for authentication and exchanges routing information used to compute routes. RIPng is a UDP-based protocol and uses UDP port 521 and the multicast address FF02::9. Similar to the other two versions, the longest network path cannot exceed 15 hops. 

Default Administrative Distance
Routing Protocols Administrative Distance
Connected interface 0
Static route out of an interface 0
Static route to next hop 1
EIGRP Summary Route 5
External BGP 20
Internal EIGRP 90
OSPF 110
IS-IS 115
RIP version 1 and 2 120
External EIGRP 170
Internal BGP 200



Enabling RIP in Cisco ASR (optional)

This task enables RIP routing and establishes a RIP routing process. Although you can configure RIP before you configure an IP address, no RIP routing occurs until at least one IP address is configured.

configuration command enabling rip from pivit global

Customizing RIP

This task describes how to customize RIP for network timing and the acceptance of route entries.

configuration command customizing rip from pivit global

Control Routing Information

This task describes how to control or prevent routing update exchange and propagation. Some reasons to control or prevent routing updates are:

  • To slow or stop the update traffic on a WAN link— if we do not control update traffic on an on-demand WAN link then the link remains up. By default, RIP routing updates occur every 30 seconds.
  • To prevent routing loops— if we have redundant paths or are redistributing routes into another routing domain then we may want to filter the propagation of one of the paths.

configuration command to control routing information in rip from pivit global

Creating a Route Policy for RIP

This task defines a route policy and shows how to attach it to an instance of a RIP process. Route policies can be used to:

  • Control routes sent and received
  • Control which routes are redistributed
  • Control origination of the default route

configuration command to create a route policy for rip from pivit global

Configuring RIP Authentication Keychain

All keychains need to be configured in Cisco IOS XR keychain database using configuration below are the configurations details

configuration command when configuring rip authentication keychain from pivit global

All keychains need to be configured in Cisco IOS XR keychain database using configuration commands described in Implementing Keychain Management module of System Security Configuration Guide for Cisco ASR 9000 Series Routers before they can be applied to a RIP interface/VRF.

configuration command in keychain database in rip from pivit global

RIP Show Commands

show command for rip configuration from pivit global

OSPF Highlight

As a link-state protocol, the OSPF analyzes sources such as speed, cost, and path congestion while identifying the shortest path for data. With OSPF, the router consolidates routing table by getting only required information from the neighboring devices. It never gets the entire routing table of the devices which simplifies the protocol and boosts efficiency. Typically, OSPF fits best in large enterprise networks but can be extremely effective in small networks as well.

OSPF routing protocol does require advanced knowledge about complex networks whereas RIP is much simpler. OSPF converges faster than RIP, and the protocol has better load balancing. A quick fault of using OSPF is that it doesn't scale when there are more routers added to the network and this makes it unsuitable for routing across the Internet. That will wrap up OSPF for today. Click below to learn more about routing protocols and OSPF:

About PivIT Global

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