IS-IS Configuration Guide

1. Introduction to RBFS IS-IS

The RtBrick Full Stack (RBFS) is a distributed, web-scale network operating system based on micro-service architecture and packaged in a Linux container currently based on Ubuntu 18.04. The RBFS decreases the complexity of a network by providing users with capabilities such as composability, programmability, and elasticity in a visionary way.

The RBFS operating system operates on the leaf and spine framework. This framework provides the network operators with methods to configure and manage a network brick by brick, and provides full control of the network so the focus can be on the deployment of the new services and not the constant juggling of hardware. The Intermediate System-to-Intermediate System (IS-IS) protocol is an interior gateway protocol (IGP) that uses link-state information to make routing decisions.

1.1. IS-IS Overview

IS-IS, or Intermediate System to Intermediate System, is an open standard routing protocol. ISO published the standard as a way to route datagrams as part of their OSI stack. IETF later republished the standard, and added IP route support.

It is a link-state routing protocol, similar to OSPF. It forms neighbor adjacencies, has areas, exchanges link-state packets, builds a link-state database and runs the Dijkstra SPF algorithm to find the best path to each destination, which is installed in the routing table.

This guide provides the various IS-IS configuration and show CLI commands for RBFS.

2. Configuring IS-IS

The basic IS-IS configuration tasks that must be performed are:

enable IS-IS protocol
configure IS-IS Instance
- configure system ID
- configure area addresses
- configure instance level
configure interfaces
configure address-family

2.1. Entering configuration mode

The following example shows how to enter the configuration mode.

root@rtbrick:~$ cli
root@rtbrick: op> switch-mode config
Activating syntax mode : cfg [config]
root@rtbrick: cfg>

From this prompt, you can enter the set commands to configure the various IS-IS components.

2.2. Enabling IS-IS Protocol

To enable IS-IS, you must configure the ISIS protocol under a specific instance.

set instance <instance> protocol isis

instance

Name of the IS-IS instance

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis
root@rtbrick: cfg> commit

2.3. Configuring an IS-IS Instance

After enabling IS-IS, the following parameters can be configured in an instance.

2.3.1. Configure the System ID

A system ID uniquely identifies a device.

set instance <instance> protocol isis system-id <system_id>

instance

Name of the IS-IS instance

system_id

specifies the system ID of the device.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis system-id 1920.0100.4001
root@rtbrick: cfg> commit

2.3.2. Configuring the ISO Area Addresses

set instance <instance> protocol isis area <area>

instance

Name of the IS-IS instance

area

The area can be represented in 1, 3, 5, 13 bytes format.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis area 49.000/24
root@rtbrick: cfg> commit

2.3.3. Configuring the Holding Time

set instance <instance> protocol isis holding-time <holding_time>

instance

Name of the IS-IS instance

holding-time

Specifies how long a neighbor should consider this routing device to be operative without receiving another hello packet.

Default value: 30 seconds

Range: 1 through 65535 seconds

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis holding-time 45
root@rtbrick: cfg> commit

2.3.4. Configuring the SRGB Base

set instance <instance> protocol isis srgb-base <srgb_base>

instance

Name of the IS-IS instance

srgb_base

Specifies the segment routing global block (SRGB) in source packet routing.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis srgb-base 10000
root@rtbrick: cfg> commit

2.3.5. Configuring the SRGB Index Range

set instance <instance> protocol isis srgb-index-range <srgb_range>

instance

Name of the IS-IS instance

srgb_range

Specifies the index range of the SRGB label block.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis srgb-index-range 1000
root@rtbrick: cfg> commit

2.3.6. Configuring the Host Name

set instance <instance> protocol isis <hostname>

instance

Name of the IS-IS instance

hostname

Specifies the hostname mapped to the system identifier.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis hostname SPINE1
root@rtbrick: cfg> commit

2.3.7. Configuring the Authentication Type

set instance <instance> protocol isis authentication level-1 type <level1_authentication_type>

instance

Name of the IS-IS instance

level1_authentication_type

Enables you to specify the authentication scheme for IS-IS. If you enable authentication, you must specify a password by including the authentication-key statement.

The following authentication types are supported:

clear_text
md5
sha1

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 type md5
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 type md5
root@rtbrick: cfg> commit

2.3.8. Configuring the Authentication Keys

set instance <instance> protocol isis authentication level-1 key1-plain-text <level1_authentication_key>

set instance <instance> protocol isis authentication level-2 key1-plain-text <level2_authentication_key>

set instance <instance> protocol isis authentication level-1 key2-plain-text <level1_authentication_key2>

set instance <instance> protocol isis authentication level-2 key2-plain-text <level2_authentication_key2>

instance

Name of the IS-IS instance

level1_authentication_key level2_authentication_key level1_authentication_key2 level2_authentication_key2

The level-1/level-2 authentication keys specify the authentication keys (passwords) that are used by the neighboring routing devices to verify the authenticity of packets sent from this interface. For the key to work, you also must include the authentication-type statement.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key1-plain-text testkey1
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key2-plain-text testkey2
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key1-plain-text testkey1
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key2-plain-text testkey2
root@rtbrick: cfg> commit

2.3.9. Configuring the Authentication Key ID

set instance <instance> protocol isis authentication level-1 key-id1 <level1_authentication_key_id>

set instance <instance> protocol isis authentication level-1 key-id2 <level1_authentication_key_id2>

set instance <instance> protocol isis authentication level-2 key-id1 <level2_authentication_key_id>

set instance <instance> protocol isis authentication level-2 key-id2 <level2_authentication_key_id2>

instance

Name of the IS-IS instance

level1_authentication_key_id level1_authentication_key_id2 level2_authentication_key_id level2_authentication_key_id2

The key ID allows you to specify the key identifiers for level-1/level-2 authentication.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key-id1 100
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key-id2 200
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key-id1 100
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key-id2 200
root@rtbrick: cfg> commit

2.3.10. Configuring the Authentication Check

set instance <instance> protocol isis authentication level-1 check <level1_authentication_check>

set instance <instance> protocol isis authentication level-2 check <level2_authentication_check>

instance

Name of the IS-IS instance

level1_authentication_check level2_authentication_check

The level-1/level-2 authentication check parameter specifies an authentication check to reject PDUs that do not match the type or key requirements. You can enable or disable the authentication check.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 check disable
root@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 check disable
root@rtbrick: cfg> commit

Configuration example

admin@rtbrick:~$ cli
admin@rtbrick: op> switch-mode config
Activating syntax mode : cfg [config]
admin@rtbrick: cfg> set instance ip2vrf protocol isis system-id 1920.0100.4001
admin@rtbrick: cfg> set instance ip2vrf protocol isis area 49.000/24
admin@rtbrick: cfg> set instance ip2vrf protocol isis holding-time 45
admin@rtbrick: cfg> set instance ip2vrf protocol isis srgb-base 10000
admin@rtbrick: cfg> set instance ip2vrf protocol isis srgb-index-range 1000
admin@rtbrick: cfg> set instance ip2vrf protocol isis hostname SPINE1
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 type md5
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key1-plain-text testkey1
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 key2-plain-text testkey2
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-1 check disable
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 type md5
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key1-plain-text testkey1
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 key2-plain-text testkey2
admin@rtbrick: cfg> set instance ip2vrf protocol isis authentication level-2 check disable
admin@rtbrick: cfg> commit
admin@rtbrick: cfg>

3. Configuring IS-IS Interface

By default, there are no interfaces associated with IS-IS.You must configure at least one IS-IS interface for ISIS adjacency formation.

After enabling IS-IS, you need to specify on which interface IS-IS will be run with the following command:

set instance <instance> protocol isis interface <interface>

instance

Name of the IS-IS instance

interface

Name of the interface

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0
root@rtbrick: cfg> commit

3.1. Configuring the Interface Type

set instance <instance> protocol isis interface <interface> type <interface_type>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

interface_type

The interface_type specifies the interface type. NOTE: The point-to-point is the default interface type and hence you actually do not need to configure it.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 type point-to-point
root@rtbrick: cfg> commit

3.2. Configuring the Interface Adjacency

set instance <instance> protocol isis interface <interface> level-1 adjacency-disable <level1_disable>

set instance <instance> protocol isis interface <interface> level-2 adjacency-disable <level2_disable>

These commands allow you to disable level-1/level-2 adjacencies on an interface.

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

level1_disable level2_disable

These parameters allow you to enable to disable the level-1/level-2 interface adjacency

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-1 adjacency-disable true
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-2 adjacency-disable true
root@rtbrick: cfg> commit

3.3. Configuring the Interface Level Metric

set instance <instance> protocol isis interface <interface> level-1 metric <level1_metric>

set instance <instance> protocol isis interface <interface> level-2 metric <level2_metric>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

level1_metric level2_metric

These parameters allow you to specify the interface level-1/level-2 metric value. If the metric value is not set, the default value is set to 1000000.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-1 metric 10
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-2 metric 10
root@rtbrick: cfg> commit

3.4. Configuring the IS-IS interfaces as passive

set instance <instance> protocol isis interface <interface> passive <is_passive>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

is_passive

This parameter sets the interface in passive mode. In this mode, no IS-IS hello packets are sent out on the interface and no IS-IS adjacencies are created. But the IP prefixes will be mentioned in the self LSP to make the network reachable via other links. The is_passive parameter can be configured as one of two values: true or false.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 passive true
root@rtbrick: cfg> commit

3.5. Configuring IS-IS LSP Interval

set instance <instance> protocol isis interface <interface> lsp-interval <lsp_interval>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

lsp_interval

Specifies the link-state PDU interval time.

The default interval time is 100 milliseconds.

The range is 1 to 1000 milliseconds.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 lsp-interval 600
root@rtbrick: cfg> commit

3.6. Configuring the Interface System ID

set instance <instance> protocol isis interface <interface> system-id <local_system_id>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

local_system_id

The local_system_id specifies the system ID of the device.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 system-id 2af0.1100.da44
root@rtbrick: cfg> commit

3.7. Configuring the Segment Routing IPv4/IPv6 Index

set instance <instance> protocol isis interface <interface> segment-routing ipv4 index <ipv4_sid>

set instance <instance> protocol isis interface <interface> segment-routing ipv6 index <ipv6_sid>

set instance <instance> protocol isis interface <interface> segment-routing ipv4 anycast-index <ipv4_anycast_sid>

set instance <instance> protocol isis interface <interface> segment-routing ipv6 anycast-index <ipv6_anycast_sid>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

ipv4_sid

ipv6_sid

ipv4_anycast_sid

ipv6_anycast_sid

These parameters specify the segment routing IPv4/IPv6 index

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 segment-routing ipv4 index 100
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 segment-routing ipv6 index 200
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 segment-routing ipv4 anycast-index 300
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 segment-routing ipv6 anycast-index 400
root@rtbrick: cfg> commit

3.8. Configuring the Level-1/Level-2 SNP Authentication

set instance <instance> protocol isis interface <interface> level-1 snp-authentication <level1_snp_authentication>

set instance <instance> protocol isis interface <interface> level-2 snp-authentication <level2_snp_authentication>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

level1_snp_authentication level2_snp_authentication

These parameters allow you to specify the Sequence Number PDU (SNP) Authentication. You can either enable or disable the SNP authentication.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-1 snp-authentication disable
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-2 snp-authentication disable

root@rtbrick: cfg> commit

3.9. Configuring the Level-1/Level-2 Hello Authentication

set instance <instance> protocol isis interface <interface> level-1 hello-authentication <level1_hello_authentication>

set instance <instance> protocol isis interface <interface> level-2 hello-authentication <level2_hello_authentication>

instance

Name of the IS-IS instance

interface

Name of the IS-IS interface

level1_hello_authentication level2_hello_authentication

These parameters can be used to enable or disable the authentication for hello packets.

Example

root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-1 hello-authentication disable
root@rtbrick: cfg> set instance ip2vrf protocol isis interface memif-1/2/1/0 level-2 hello-authentication disable
root@rtbrick: cfg> commit

4. Configuring Address Family

The address-family command allows you to enable the address families that IS-IS will route and configure settings that are distinct to that address family. The address families supported are IPv4 unicast and IPv6 unicast.

4.1. Configuring Route Redistribution

set instance <instance> protocol isis address-family <afi> <safi> redistribute level-1 <source>

set instance <instance> protocol isis address-family <afi> <safi> redistribute level-2 <source>

instance

Name of the IS-IS instance

afi

safi

These parameters specify the address-family.

source

Specifies the source from which the routes are to be redistributed from. The available options are bgp, ospf, direct, and static.

Configuration Example

root@rtbrick: cfg> set instance ip2vrf protocol isis address-family ipv4 unicast redistribute level-1 static
root@rtbrick: cfg> set instance ip2vrf protocol isis address-family ipv4 unicast redistribute level-2 static
admin@rtbrick: cfg> commit

5. IS-IS Show Configuration

The following examples show how to display the IS-IS running configurations.

root@rtbrick: cfg> show config global protocol isis
{
  "rtbrick-network-instance:isis": {
    "flood-filter": [
      {
        "filter-name": "spine1_lsr1_flood_filter",
        "ordinal": 1,
        "ordinal-name": "spine1",
        "system-id": "1920.0100.4001",
        "action": "flood"
      }
    ]
  }
}

root@rtbrick: cfg> show config instance ip2vrf protocol isis
{
  "rtbrick-config:isis": {
    "system-id": "1920.0100.4001",
    "holding-time": 45,
    "area": "49.0001/24",
    "hostname": "SPINE1",
    "authentication": {
      "level-1": {
        "type": "md5",
        "key1-encrypted-text": "$2630a640edb7d6b5cf66795402f66ed20",
        "key2-encrypted-text": "$21b4a9a2a404ea5878cb2aa5c5a4a716b",
        "check": "disable"
      },
      "level-2": {
        "type": "md5",
        "key1-encrypted-text": "$2630a640edb7d6b5cf66795402f66ed20",
        "key2-encrypted-text": "$21b4a9a2a404ea5878cb2aa5c5a4a716b",
        "check": "disable"
      }
    },
    "srgb-base": 10000,
    "srgb-index-range": 1000,
    "interface": [
      {
        "name": "lo-0/0/1/0",
        "segment-routing": {
          "ipv4": {
            "index": 100
          },
          "ipv6": {
            "index": 200
          }
        }
      },
      {
        "name": "lo-0/0/2/0",
        "segment-routing": {
          "ipv4": {
            "anycast-index": 300
          },
          "ipv6": {
            "anycast-index": 400
          }
        }
      },
      {
        "name": "memif-1/2/1/0",
        "flood-filter": "spine1_lsr1_flood_filter",
        "type": "point-to-point",
        "lsp-interval": 600,
        "passive": true,
        "level-1": {
          "snp-authentication": "disable",
          "hello-authentication": "disable",
          "metric": 10,
          "adjacency-disable": "true"
        },
        "level-2": {
          "snp-authentication": "disable",
          "hello-authentication": "disable",
          "metric": 10,
          "adjacency-disable": "true"
        }
      }
    ],
    "address-family": [
      {
        "afi": "ipv4",
        "safi": "unicast",
        "redistribute": [
          {
            "source": "static",
            "destination-subtype": "level-1"
          },
          {
            "source": "static",
            "destination-subtype": "level-2"
          }
        ]
      }
    ]
  }
}

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