Configuring RIP Triggered Updates

By default RIP sends its updates on a fixed interval which can consume bandwidth. Triggered updates is a method that RIP can use so only updates are sent when the routes change. This lab will discuss and demonstrate the configuration and verification of RIP Triggered Updates.

Real World Application & Core Knowledge

So looking back at the architecture of RIP you’ll remember that RIP will send all its routing table in updates to its neighboring routers, in by doing so bandwidth is required. This bandwidth over a WAN link can be excessive and even more excessive when you have modified the RIP timers. No need to fear, triggered updates are here!!!

Proposed in RFC2092, triggered updates only send updates to neighboring routers under specific conditions to conserve bandwidth. Triggered updates are exactly how they sound. Updates are not send to neighboring routers unless one of four things happen to cause the update to be sent which include the following;

The router receives a specific request for an update.
Information from another interfaces has caused a modification to the RIP database causing an update to be triggered.
An interface goes up or down; in which case a partial database update is sent.
A router is powered on thus triggering an update of the FULL database.

The configuration of triggered updates is done on a per interface basis and must be configured on both sides of the link. The command used to enable triggered updates is ip rip triggered You can verify the configuration via the show ip protocols command.

This lab will use the same logical topology as used previous Lab 7-3 as shown below;

In this lab you will configure triggered updates on the point to point Frame relay link between R2 and R3.

Familiarize yourself with the following new command(s);

Command	Description
ip rip triggered	This command is executed under interface configuration mode to enable the RIP RFC2092 Triggered Updates extension.

Lab Prerequisites

If you are using GNS3 than load the Free CCNA Workbook GNS3 topology than start devices; R1, R2 and R3.
Establish a console session with devices R1, R2 and R3 than load the initial configurations provided below by copying the config from the textbox and pasting it into the respected routers console.

!################################################## !# Free CCNA Workbook Lab 7-4 R1 Initial Config # !################################################## ! enable configure terminal ! hostname R1 ! interface Loopback0 description ### SIMULATED NETWORK ### ip address 10.70.10.1 255.255.255.0 ! interface Serial0/0 description ### PHYSICAL FRAME RELAY INTERFACE ### no ip address encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp ! interface Serial0/0.122 point-to-point description ### FRAME RELAY LINK TO R2 ### ip address 10.70.12.1 255.255.255.252 frame-relay interface-dlci 122 ! interface Serial0/0 no shut ! interface Serial0/1 description ### PPP Link TO R2 ### ip address 10.70.21.1 255.255.255.252 encapsulation ppp serial restart-delay 0 clock rate 128000 no shut ! exit ! router rip version 2 network 10.0.0.0 timers basic 30 40 10 60 ! end !################################################## !# Free CCNA Workbook Lab 7-4 R2 Initial Config # !################################################## ! enable configure terminal ! hostname R2 ! interface Loopback0 description ### SIMULATED NETWORK ### ip address 10.70.20.1 255.255.255.0 ! interface Serial0/0 description ### PHYSICAL FRAME RELAY INTERFACE ### no ip address encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp ! interface Serial0/0.221 point-to-point description ### FRAME RELAY LINK TO R1 ### ip address 10.70.12.2 255.255.255.252 frame-relay interface-dlci 221 ! interface Serial0/0.223 point-to-point description ### FRAME RELAY LINK TO R3 ### ip address 10.70.23.1 255.255.255.252 frame-relay interface-dlci 223 ! interface Serial0/0 no shut exit ! interface Serial0/1 description ### PPP LINK TO R1 ### ip address 10.70.21.2 255.255.255.252 encapsulation ppp serial restart-delay 0 clock rate 128000 no shut exit ! router rip version 2 network 10.0.0.0 timers basic 30 40 10 60 ! end !################################################## !# Free CCNA Workbook Lab 7-4 R3 Initial Config # !################################################## ! enable configure terminal ! hostname R3 ! interface Loopback0 description ### SIMULATED NETWORK ### ip address 10.70.30.1 255.255.255.0 ! interface Serial0/0 description ### PHYSICAL FRAME RELAY INTERFACE ### no ip address encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp ip rip advertise 10 ! interface Serial0/0.322 point-to-point description ### FRAME RELAY LINK TO R2 ### ip address 10.70.23.2 255.255.255.252 frame-relay interface-dlci 322 ! interface Serial0/0 no shut exit ! router rip version 2 network 10.0.0.0 timers basic 30 40 10 60 ! end

Lab Objectives

Configure the point-to-point Frame Relay link between R2 and R3 to use triggered rip updates to conserve bandwidth.
Verify the RIP Triggered updates configuration.

Lab Instruction

Objective 1. – Configure the point-to-point Frame Relay link between R2 and R3 to use triggered rip updates to conserve bandwidth.

R2#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#interface Serial0/0.223
R2(config-subif)#ip rip triggered
R2(config-subif)#end
R2#

R3#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R3(config)#interface Serial0/0.322
R3(config-subif)#ip rip triggered
R3(config-subif)#end
R3#

Objective 2. – Verify the RIP Triggered updates configuration.

This can be done using the show ip protocols command as shown below;

R2#show ip protocols
Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 14 seconds
  Invalid after 40 seconds, hold down 0, flushed after 60
  Redistributing: rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    Serial0/0.221         2     2                                    
    Serial0/0.223         2     2          Yes                       
    Serial0/1             2     2                                    
    Loopback0             2     2                                    
  Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    10.0.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    10.70.12.1            120      00:00:07
    10.70.23.2            120      00:01:28
    10.70.21.1            120      00:00:18
  Distance: (default is 120)

R2#

R3#show ip protocols
Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 23 seconds
  Invalid after 40 seconds, hold down 0, flushed after 60
  Redistributing: rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    Serial0/0.322         2     2          Yes                       
    Loopback0             2     2                                    
  Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    10.0.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    10.70.23.1            120      00:00:09
  Distance: (default is 120)

R3#

Examine the show ip protocols information and you’ll see that Serial0/0.223 has “yes” under triggered on R2 and Serial0/0.322 has yes under triggered on R3.

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