docs: Update OpenFabric page to VyOS 1.5 standards (#2060) (#2094)

* docs: Update OpenFabric page to VyOS 1.5 standards

* Update openfabric.md

* Update openfabric.md

* Update openfabric.md

(cherry picked from commit 754295dcb7c048e8142b36eb90b9a0b18cad506d)

# Conflicts:
#	docs/configuration/protocols/openfabric.md

Co-authored-by: LiudmylaNad <l.nadolina@vyos.io>

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+---
+myst:
+  html_meta:
+    description: |
+      OpenFabric is a routing protocol derived from IS-IS that provides
+      link-state routing with optimized flooding, making it well-suited
+      for spine-leaf topologies.
+    keywords: openfabric, isis, link-state, spine-leaf, fabric, net, lsp
+---
+
+(openfabric)=
+
+# OpenFabric
+
+% stop_vyoslinter
+OpenFabric, specified in [draft-white-openfabric-06.txt](https://datatracker.ietf.org/doc/html/draft-white-openfabric-06),
+% start_vyoslinter
+is a routing protocol derived from IS-IS. It provides link-state routing with
+optimized flooding, making it well-suited for spine-leaf topologies.
+
+OpenFabric is a dual-stack protocol. A single instance can simultaneously
+route both IPv4 and IPv6 traffic.
+
+## Configuration
+
+### Mandatory settings
+
+Each OpenFabric router must be configured with a unique
+{abbr}`NET (Network Entity Title)`, the
+{abbr}`CLNS (Connectionless Network Service)` equivalent of a Router ID. The
+6-byte system identifier portion of the NET must be unique across the fabric.
+
+```{cfgcmd} set protocols openfabric net \<network-entity-title\>
+
+**Configure the Network Entity Title (NET) for the router.**
+
+A typical NET looks like ``49.0001.1921.6800.1002.00``.
+
+The NET consists of the following parts:
+
+- **{abbr}`AFI (Authority and Format Identifier)`** (`49`): OpenFabric
+  conventionally uses AFI value 49 for private addressing.
+- **Area identifier** (`0001`): The area number within the fabric (in this
+  case, Area 1).
+- **System identifier** (`1921.6800.1002`): Uniquely identifies the router
+  within the fabric. We recommend deriving this value from the router IP
+  address or MAC address. To construct the system identifier from an IPv4
+  address (for example, `192.168.1.2`):
+
+  - Pad each octet with leading zeros: `192.168.1.2` → `192.168.001.002`.
+  - Regroup the digits into three 4-digit blocks: `192.168.001.002` →
+    `1921.6800.1002`.
+
+- **NET selector** (`00`): Must always be `00` to indicate the local system.
+```
+
+Example:
+
+```none
+set protocols openfabric net 49.0001.1921.6800.1002.00
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> address-family \<ipv4|ipv6\>
+
+**Configure the named OpenFabric domain on a specific interface for the
+given address family (IPv4 or IPv6).**
+
+For dual-stack operation, run the command twice: once with `ipv4` and once
+with `ipv6`.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth1 address-family ipv4
+set protocols openfabric domain fabric1 interface eth1 address-family ipv6
+```
+
+### OpenFabric global configuration
+
+```{cfgcmd} set protocols openfabric domain \<name\> domain-password \<plaintext-password|md5\> \<password\>
+
+**Configure the authentication password for the specified OpenFabric
+domain.**
+
+The password can be specified as either plain text or
+an {abbr}`MD5 (Message-Digest Algorithm 5)` hash.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 domain-password md5 'shared-secret'
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> purge-originator
+
+**Enable {abbr}`POI (Purge Originator Identification)` for the specified
+OpenFabric domain.**
+
+POI is defined in RFC 6232.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 purge-originator
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> set-overload-bit
+
+**Configure the overload bit for the specified OpenFabric domain.**
+
+This instructs other routers in the domain not to use this router for
+transit traffic.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 set-overload-bit
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> log-adjacency-changes
+
+**Enable logging of adjacency state changes in the specified OpenFabric
+domain.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 log-adjacency-changes
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> fabric-tier \<0-14\>
+
+**Configure a static tier number for the specified OpenFabric domain.**
+
+The router advertises the tier value to indicate its location in the
+OpenFabric domain.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 fabric-tier 1
+```
+
+### Interface configuration
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> hello-interval \<1-600\>
+
+**Configure the interval, in seconds, at which the router transmits Hello
+packets on this interface.**
+
+Hello packets are exchanged with neighbors to establish and maintain
+adjacencies.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 hello-interval 5
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> hello-multiplier \<2-100\>
+
+**Configure the multiplier used to compute the Hello hold time on the
+specified interface.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 hello-multiplier 3
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> metric \<0-16777215\>
+
+**Configure the routing metric for the specified interface.**
+
+This metric is used in path selection to determine the most efficient
+route. Lower metrics indicate preferred paths.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 metric 100
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> passive
+
+**Enable passive mode for the specified interface.**
+
+In passive mode, the router does not send Hello packets on the interface
+and does not form adjacencies.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 passive
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> password \<plaintext-password|md5\> \<password\>
+
+**Configure the authentication password for the specified interface.**
+
+The password can be specified as either plain text or
+an {abbr}`MD5 (Message-Digest Algorithm 5)` hash.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 password plaintext-password link-secret
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> csnp-interval \<1-600\>
+
+**Configure the interval, in seconds, at which
+{abbr}`CSNPs (Complete Sequence Number PDUs)` are sent on the specified
+interface.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 csnp-interval 10
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> interface \<interface\> psnp-interval \<0-120\>
+
+**Configure the interval, in seconds, at which
+{abbr}`PSNPs (Partial Sequence Number PDUs)` are sent on the specified
+interface.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 interface eth0 psnp-interval 2
+```
+
+### Timers
+
+```{cfgcmd} set protocols openfabric domain \<name\> lsp-gen-interval \<1-120\>
+
+**Configure the minimum interval, in seconds, between successive
+generations of the same {abbr}`LSP (Link State PDU)` in the OpenFabric
+domain.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 lsp-gen-interval 5
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> lsp-refresh-interval \<1-65235\>
+
+**Configure the LSP refresh interval, in seconds, for the OpenFabric
+domain.**
+```
+
+```{note}
+The value must be lower than `max-lsp-lifetime`. Otherwise, LSPs will
+time out before they can be refreshed.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 lsp-refresh-interval 900
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> max-lsp-lifetime \<360-65535\>
+
+**Configure the maximum lifetime, in seconds, for LSPs in the OpenFabric
+domain.**
+
+By default, LSPs remain in the link-state database for 1200 seconds and
+are deleted if they are not refreshed.
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 max-lsp-lifetime 1200
+```
+
+```{cfgcmd} set protocols openfabric domain \<name\> spf-interval \<1-120\>
+
+**Configure the minimum interval, in seconds, between consecutive
+{abbr}`SPF (Shortest Path First)` calculations in the OpenFabric domain.**
+```
+
+Example:
+
+```none
+set protocols openfabric domain fabric1 spf-interval 5
+```
+
+## Example
+
+The following example demonstrates a basic OpenFabric configuration between
+two routers.
+
+**Node 1:**
+
+```none
+set interfaces loopback lo address '198.51.100.1/32'
+set interfaces ethernet eth1 address '192.0.2.1/24'
+
+set protocols openfabric domain VyOS interface eth1 address-family ipv4
+set protocols openfabric domain VyOS interface lo address-family ipv4
+set protocols openfabric domain VyOS interface lo passive
+set protocols openfabric net '49.0001.1980.5110.0001.00'
+```
+
+**Node 2:**
+
+```none
+set interfaces loopback lo address '198.51.100.2/32'
+set interfaces ethernet eth1 address '192.0.2.2/24'
+
+set protocols openfabric domain VyOS interface eth1 address-family ipv4
+set protocols openfabric domain VyOS interface lo address-family ipv4
+set protocols openfabric domain VyOS interface lo passive
+set protocols openfabric net '49.0001.1980.5110.0002.00'
+```
+
+After committing the configuration, verify the neighbor adjacencies on both
+nodes: 
+
+```none
+vyos@node-1:~$ show openfabric neighbor
+show openfabric neighbor
+Area VyOS:
+  System Id           Interface   L  State        Holdtime SNPA
+  node-2              eth1        2  Up            27      2020.2020.2020
+
+
+vyos@node-2:~$ show openfabric neighbor
+show openfabric neighbor
+Area VyOS:
+  System Id           Interface   L  State        Holdtime SNPA
+  node-1              eth1        2  Up            30      2020.2020.2020
+```
+
+Verify that the OpenFabric routes have successfully populated:
+
+```none
+vyos@node-1:~$ show ip route openfabric
+show ip route openfabric
+Codes: K - kernel route, C - connected, S - static, R - RIP,
+       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
+       T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
+       f - OpenFabric,
+       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
+       t - trapped, o - offload failure
+
+f   192.0.2.0/24 [115/20] via 192.0.2.2, eth1 onlink, weight 1, 00:00:10
+f>* 198.51.100.2/32 [115/20] via 192.0.2.2, eth1 onlink, weight 1, 00:00:10
+
+vyos@node-2:~$ show ip route openfabric
+show ip route openfabric
+Codes: K - kernel route, C - connected, S - static, R - RIP,
+       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
+       T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
+       f - OpenFabric,
+       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
+       t - trapped, o - offload failure
+
+f   192.0.2.0/24 [115/20] via 192.0.2.1, eth1 onlink, weight 1, 00:00:48
+f>* 198.51.100.1/32 [115/20] via 192.0.2.1, eth1 onlink, weight 1, 00:00:48
+```