IS-IS Lab 10 Metric

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Download Lab: VIRL | EVE-NG | GNS3


Image requirements:
 Cisco IOSv (vios-adventerprisek9-m.vmdk.SPA.156-2.T)


Introduction:
This is a very small lab, the goal is to modify the metics of leaf subnets across the topology in both areas. Internal routers in areas A100 and B200 are configured with loopback interfaces to simulates local subnets, by default when enabled IS-IS on the interfaces, the metric is 10, you have to change to 50 on the routers A1, A3, and B2, B3 for loopback 172 interfaces. The IS-IS has two types of metrics, narrow and wide and can be modified in the IS-IS router configuration mode. A wide metric means that it supports a bigger metric than the original narrow one. Wide metric required when deploying IS-IS for IPv6 networks. Configure and verify a wide metric on all nodes in the topology. 


Nodes Access: 
Enable:       cisco 
Username:  cisco 
Password:   cisco 


Topology: 

 

 Lab Tasks:

1. Identify the current metrics for subnets in the topology by using the IS-IS database information. 

2. Change metrics on the routers A1, A3, B2, and B3 for interfaces loopback 172 to 50. Then verify the results of the modification.  

3. Check the current configuration for the IS-IS metric type on all nodes in the topology. 

4. Change to the wide metric across all devices. Then confirm your work with the appropriate command. 


Lab procedure:  

Step1: Use the "show isis database" command to find out the metric of subnets belong to the loopback 172 interfaces on the router A1, A3, B2, and B3.  

Verification example:

A1#show  isis database detail A1.00-00
IS-IS Level-1 LSP A1.00-00
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime/Rcvd      ATT/P/OL
A1.00-00            * 0x00000002   0x3167                1146/*         0/0/0
  Area Address: 49.a100
  NLPID:        0xCC
  Hostname: A1
  Metric: 1          IS A1.01
  IP Address:   192.168.0.1
  Metric: 1          IP 10.0.0.0 255.255.0.0
  Metric: 10         IP 172.16.0.0 255.255.255.0
  Metric: 10         IP 172.16.1.0 255.255.255.0
  Metric: 10         IP 172.16.2.0 255.255.255.0
  Metric: 10         IP 172.16.3.0 255.255.255.0
  Metric: 10         IP 172.16.4.0 255.255.255.0
  Metric: 10         IP 172.16.5.0 255.255.255.0
  Metric: 10         IP 172.16.6.0 255.255.255.0
  Metric: 10         IP 172.16.7.0 255.255.255.0
  Metric: 10         IP 192.168.0.1 255.255.255.255 


Step2: Enter the interface configuration mode and change the IS-IS metric with the following command: 

A1(config)#interface  lo172
A1(config-if)#isis metric 50 

Confirm that the metric has been changed to the new parameter. 

A1#show  isis database detail A1.00-00
IS-IS Level-1 LSP A1.00-00
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime/Rcvd      ATT/P/OL
A1.00-00            * 0x00000003   0x61F4                 987/*         0/0/0
  Area Address: 49.a100
  NLPID:        0xCC
  Hostname: A1
  Metric: 1          IS A1.01
  IP Address:   192.168.0.1
  Metric: 1          IP 10.0.0.0 255.255.0.0
  Metric: 50         IP 172.16.0.0 255.255.255.0
  Metric: 50         IP 172.16.1.0 255.255.255.0
  Metric: 50         IP 172.16.2.0 255.255.255.0
  Metric: 50         IP 172.16.3.0 255.255.255.0
  Metric: 50         IP 172.16.4.0 255.255.255.0
  Metric: 50         IP 172.16.5.0 255.255.255.0
  Metric: 50         IP 172.16.6.0 255.255.255.0
  Metric: 50         IP 172.16.7.0 255.255.255.0
  Metric: 10         IP 192.168.0.1 255.255.255.255

Step3: Narrow metric is configured by default, to verify which metric-style is enabled use show command to display the IS-IS protocol parameters.

A1#show isis protocol
  IS-IS Router: <Null Tag>
  System Id: 1921.6800.0001.00  IS-Type: level-1
  Manual area address(es):
        49.a100
  Routing for area address(es):
        49.a100
  Interfaces supported by IS-IS:
        GigabitEthernet0/1 - IP
        Loopback172 - IP
        Loopback0 - IP
  Redistribute:
    static (on by default)
  Distance for L2 CLNS routes: 110
  RRR level: none
  Generate narrow metrics: level-1-2
  Accept narrow metrics:   level-1-2
  Generate wide metrics:   none
  Accept wide metrics:     none


Step4: Configure wide style metric across the entire topology, starting with router A1.
  
A1(config)#router isis
A1(config-router)#metric-style wide  

Verify your changes with show isis protocol command.