Rate and give feedback:  Feedback Received. Thank You!

Rate and give feedback: 

X

This document helped resolve my issue

Yes No

Additional Comments

800 characters remaining

May we contact you if necessary?

Name:  

E-mail: 

Enter a valid Email ID

Need product assistance? Contact Juniper Support

Submit

This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply.

English  

English

Example: Summarizing Routes Through Route Aggregation

Requirements

No special configuration beyond device initialization is required before configuring this example.

Overview

In this example, Device R1 is connected to customer networks 10.200.1.0/24 and 10.200.2.0/24. For demonstration purposes, these routes are represented in this example as loopback interfaces on Device R1.

Device R2 has static routes configured to reach Device R1’s customer networks. Device R2 also has a routing policy configured to advertise all static routes to its neighbors in autonomous system (AS) 65001.

Device R3 is in AS 65001 and receives the static routes from Device R2. When Device R3 sends information about these routes to Device ISP, the information is summarized as a single aggregate route. The aggregate route is 10.200.0.0/16.

Device ISP injects a default route into AS 65001, and Device R3 advertises the default route.

This example shows the configuration for all of the devices and the step-by-step configuration on Device R3.

Figure 1 shows the sample network.

Figure 1: Aggregate Route Advertised to an ISP

Configuration

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Step-by-Step Procedure

1. Configure the interfaces.
   [edit interfaces]user@R3# set ge-1/2/0 unit 3 description R3->R2user@R3# set ge-1/2/0 unit 3 family inet address 10.0.2.1/30
   user@R3# set ge-1/2/1 unit 6 description R3->ISPuser@R3# set ge-1/2/1 unit 6 family inet address 10.0.45.2/30
   user@R3# set lo0 unit 3 family inet address 172.16.3.3/32

2. Configure the AS number.

   [edit routing-options]user@R3# set autonomous-system 65001
3. Configure the BGP session with the ISP device.
   [edit protocols bgp group ext]user@R3# set type externaluser@R3# set peer-as 65000user@R3# set neighbor 10.0.45.1
4. Configure the BGP session with Device R2.
   [edit protocols bgp group int]user@R3# set type internaluser@R3# set local-address 172.16.3.3user@R3# set neighbor 172.16.2.2

5. Configure OSPF.

   [edit protocols ospf area 0.0.0.0]user@R3# set interface ge-1/2/0.3user@R3# set interface lo0.3 passive

6. Configure the aggregate route.

   [edit routing-options]user@R3# set aggregate route 10.200.0.0/16

7. Configure the routing policy to advertise the aggregate route.

   The first term in this policy advertises the aggregate route. The second term prevents more specific routes from being advertised.

   [edit policy-options policy-statement send-aggregate]user@R3# set term 1 from protocol aggregateuser@R3# set term 1 then acceptuser@R3# set term suppress-specific-routes from route-filter 10.200.0.0/16 longeruser@R3# set term suppress-specific-routes then reject

8. Apply the aggregate route policy to the external BGP session with Device ISP.

   [edit protocols bgp group ext]user@R3# set export send-aggregate

9. Configure the routing policy to advertise the default route from Device ISP.

   [edit policy-options policy-statement send-default]user@R3# set from route-filter 0.0.0.0/0 exactuser@R3# set then accept

10. Apply the default routing policy to OSPF.

    [edit protocols ospf]user@R3# set export send-default

11. If you are done configuring the device, commit the configuration.

    [edit]user@R3# commit

Results

Confirm your configuration by issuing the show interfaces, show protocols, show policy-options, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

Verification

Confirm that the configuration is working properly.

• Verifying That Device R3 Has the Expected Routes
• Verifying That Device R3 Advertises the Aggregate Route to Device ISP

Verifying That Device R3 Has the Expected Routes

Purpose

Make sure that Device R3 has the specific static routes.

Action

inet.0: 12 destinations, 12 routes (12 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

A Destination        P Prf   Metric 1   Metric 2  Next hop        AS path
* 0.0.0.0/0          B 170        100            >10.0.45.1       65000 I
* 10.200.1.0/24      B 170        100            >10.0.2.2        I
* 10.200.2.0/24      B 170        100            >10.0.2.2        I

Meaning

The output shows that Device R3 has the specific routes to the 10.200.1.0/24 and 10.200.2.0/24 networks.

Verifying That Device R3 Advertises the Aggregate Route to Device ISP

Purpose

Make sure that Device R3 does not send the specific static routes and only sends the summarized aggregate route.

Action

inet.0: 12 destinations, 12 routes (12 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.200.0.0/16           Self                                    I

Meaning

The output shows that Device R3 sends only the summarized route to Device ISP.