(module-isis)= # IS-IS Configuration Module This configuration module configures the IS-IS routing process on Cisco IOS, Cisco NX-OS, Arista EOS, Junos (tested on vSRX), Nokia SR OS, and Nokia SR Linux. The module supports the following IS-IS features: * IPv4 and IPv6 * IS type (L1 and/or L2) * Multi-topology IPv6 (enabled by default as soon as the node has at least one IPv6 address, cannot be disabled) * Wide metrics (enabled by default, cannot be turned off) * Unnumbered IPv4 interfaces * Passive interfaces * BFD ```eval_rst .. contents:: Table of Contents :depth: 2 :local: :backlinks: none ``` ## Platform Support The following table describes per-platform support of individual IS-IS features: | Operating system | IS type | IPv6 AF | Multi
topology | Unnumbered
interfaces | IPv4
BFD | IPv6
BFD | | ------------------ | :-: | :-: | :-: | :-: | :-: | :-: | | Arista EOS | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | | Cisco ASAv | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | | Cisco IOS | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | Cisco IOS XE[^18v] | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | Cisco IOS XRv | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | | Cisco Nexus OS | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | | FRR | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | | Junos[^Junos] | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | Nokia SR Linux | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | | Nokia SR OS | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | | VyOS | ✅ | ✅ | ❌ | ❌ | ✅ | ✅ | [^18v]: Includes Cisco CSR 1000v and Cisco Catalyst 8000v [^Junos]: Includes vMX, vSRX, vPTX and vJunos-switch **Notes:** * On Arista EOS, IPv6 is enabled on all interfaces as soon as one has an IPv6 address. Arista EOS implementation of IS-IS refuses to work on interfaces with missing address families. * On VyOS, IPv6 is enabled on all interfaces as soon as one has an IPv6 address. * Cisco ASA does not support P2P IS-IS links. You could add `isis.network_type: false` to point-to-point links connecting ASA to other devices. ```{tip} See [IS-IS Integration Tests Results](https://release.netlab.tools/_html/coverage.isis) for more details. ``` ## Global Parameters * **isis.area** -- CLNS area prefix. Router address (NET) is computed from area prefix, 6-byte system ID (using **id** node attribute), and NSAP selector (.00) * **isis.type** -- IS-IS router type (**level-1**, **level-2** or **level-1-2**. Default: **level-2**) * **isis.bfd** -- enable BFD for IS-IS. This parameter could be a boolean value (*True*/*False*) or a dictionary of address families, for example: ``` isis: area: "49.0002" bfd: ipv4: True ipv6: True ``` ```{warning} Specify **‌isis.area** with a single dot (example: 49.0001) within quotes to tell the YAML parser it's not a floating-point number. ``` ## Node Parameters You can specify node parameters as global values (top-level topology elements) or within individual nodes. You can specify **isis.net** on individual nodes instead of using **isis.area** (see [example](#example) for details). **Note:** * When specifying **isis.net**, avoid values in range *area.0000.0000.0001.00* through *area.0000.0000.0099.00* as they are used for auto-generated NETs. IS-IS is automatically started on all interfaces within an autonomous system (interfaces with no EBGP neighbors; see also [](routing_external)). To disable IS-IS on an intra-AS link, set the **isis** link parameter to *False* (see also [](routing_disable)). ```{tip} The IS-IS configuration module is automatically removed from a node that does not run IS-IS on any non-loopback interface. In that case, _netlab_ generates a warning that can be turned off by setting **‌defaults.isis.warnings.inactive** to **‌False**. ``` ## Link Parameters * **isis.type** -- Link type (**level-1**, **level-2** or **level-1-2**). Recognized as a valid attribute but not implemented. Please feel free to fix the configuration templates and submit a pull request. * **isis.network_type** -- Set IS-IS network type. Valid values are **point-to-point** or *False* (do not set the network type). See also [Default Link Parameters](#default-link-parameters). * **isis.metric** or **isis.cost** -- Interface cost. Both parameters are recognized to make IS-IS configuration similar to OSPF (*metric* takes precedence over *cost*) * **isis.bfd** -- enable or disable BFD on individual interfaces. Like with the node-level **isis.bfd** parameter, this parameter could be a boolean value (*True* to enable BFD for all address families, *False* to disable IS-IS BFD on the interface) or a dictionary of address families, for example: Example: ``` links: - name: Link with IPv4-only BFD sros_r1: srlinux_r2: isis.bfd: ipv4: True ipv6: False ``` ## Default Link Parameters The number of neighbors on an interface is used to set IS-IS network type unless it's specified with **isis.network_type** link or interface attribute. Interfaces with exactly one non-host neighbor (point-to-point links) have **isis.network_type** set to **point-to-point**. When the **isis.passive** interface parameter is not set on a link or an interface, _netlab_ uses the link roles together with the link types to decide whether to include an interface in an IS-IS process and whether to make an interface passive: * External links (links with **role: external**) are not included in the IS-IS process. * Links with **role** set to **passive** are configured as *passive* IS-IS interfaces. * Interfaces connected to links with a single router or routing daemon attached are *passive* IS-IS interfaces. **Notes:** * The BGP module could set link role. Links with devices from different AS numbers attached to them get a role specified in **defaults.bgp.ebgp_role** parameter. The system default value of that parameter is **external**, excluding inter-AS links from the IS-IS process. * Management interfaces are never added to the IS-IS process. They are not in the set of device links and, thus, not considered in the IS-IS configuration template. ## Example We want to create a three-router multi-area IS-IS network: * R1 and R2 are in area 49.0001 * R3 is in area 49.0002. All devices run OSPF: ``` module: [ isis ] ``` The default IS-IS area is 49.0001: ``` isis: area: 49.0001 ``` R1 and R2 are in the default IS-IS area. We'll specify explicit NET for R2: ``` nodes: r1: device: iosv r2: device: eos isis: net: 49.0001.0000.cafe.0002.00 ``` R3 is in area 49.0002. ``` nodes: r3: device: nxos isis: area: 49.0002 ``` Each router has a stub interface: ``` links: - r1: - r2: - r3: ``` We'll specify per-link IS-IS metric on the link between R1 and R2: ``` links: - isis: metric: 10 r1: r2: ``` We'll specify asymmetric per-node IS-IS metrics on the link between R2 and R3: ``` links: - r2: isis: metric: 20 r3: isis: metric: 30 ``` ### Resulting Device Configurations The above topology generates the following device configurations: #### R1 (Cisco IOS) ``` router isis Gandalf log-adjacency-changes hostname dynamic is-type level-2 metric-style wide net 49.0001.0000.0000.0001.00 passive-interface GigabitEthernet0/1 address-family ipv4 unicast ! interface Loopback0 ip router isis Gandalf ! interface GigabitEthernet0/1 ip router isis Gandalf ! interface GigabitEthernet0/2 ip router isis Gandalf isis metric 10 ``` #### R2 (Arista EOS) ``` router isis Gandalf log-adjacency-changes is-hostname r2 is-type level-2 net 49.0001.0000.cafe.0002.00 address-family ipv4 unicast ! interface Loopback0 isis enable Gandalf ! interface Ethernet1 isis enable Gandalf isis passive ! interface Ethernet2 isis enable Gandalf isis metric 10 ! interface Ethernet3 isis enable Gandalf isis metric 20 ``` #### R3 (Cisco Nexus OS) ``` feature isis ! router isis Gandalf log-adjacency-changes is-type level-2 hostname dynamic net 49.0002.0000.0000.0003.00 address-family ipv4 unicast ! interface Loopback0 ip router isis Gandalf ! interface Ethernet1/1 ip router isis Gandalf isis passive-interface level-1-2 ! interface Ethernet1/2 ip router isis Gandalf isis metric 30 level-1 isis metric 30 level-2 ``` ### Complete Network Topology ``` module: [ isis ] isis: area: 49.0001 nodes: r1: device: iosv r2: device: eos isis: net: 49.0001.0000.cafe.0002.00 r3: device: nxos isis: area: 49.0002 links: - r1: - r2: - r3: - isis: metric: 10 r1: r2: - r2: isis: metric: 20 r3: isis: metric: 30 ```