Intro

The script visualizes ISIS Segment Routing domain, while provides number of options, Node-SID/Interface/Adj-SID labels, simple SFP path calculation and adjacency SID matrix. It uses actively pySROS, NetworkX and matplotlib. The script designed for use with Nokia 7x50 router family. Tested using SROS 23.3.R2.

A:admin@sre3# show version
TiMOS-B-23.3.R2 both/x86_64 Nokia 7750 SR Copyright (c) 2000-2023 Nokia.
All rights reserved. All use subject to applicable license agreements.

Prerequisites and Installation

Basically the same as for pySROS NETCONF configured on all nodes of SR domain. Configuration example could be found here. It's recommended to take a clone of YANG models in respect of your SROS version, in order to avoid longer time downloading from the NEs and faster execution.

NETCONF user should have the following GNMI paths accessible in R/O mode:

'/nokia-state:state/port[port-id=PORT]/hardware-mac-address'
'/nokia-conf:configure/router[router-name="Base"]/interface[interface-name=INTERFACE]'
'/nokia-state:state/router[router-name="Base"]/isis[isis-instance="0"]'
'/nokia-conf:configure/router[router-name="Base"]/mpls-labels/sr-labels'

Before use required packages have to be installed via pip.

pip3 install -r requirements.txt

Limitations

• ISIS instance number should be 0.
• Supports not more than two p2p interfaces between the same pair of routers.
• Supports P2P interfaces only.

Usage

usage: main.py [-h] [-c CONFIG] [-y YANG] [-n NPORT] [-u USER] [-p PWD] [-a] [-g] [-s SRC] [-d DST]

Visualizes ISIS Segment Routing domain, Node-SID/Interface/Adj-SID labels, performs simple SFP path calculation and provides adjacency SID matrix.

Draw ISIS SR domain graph.

options:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Configuration file name.
  -y YANG, --yang YANG  YANG models directory.
  -n NPORT, --nport NPORT
                        default NETCONF port.
  -u USER, --user USER  default NETCONF username.
  -p PWD, --pwd PWD     default NETCONF password.
  -a, --adjmatrix       Adjacency matrix.
  -g, --graph           Draw Graph.
  -s SRC, --src SRC     Source node.
  -d DST, --dst DST     Destination node.

Drawing Graph

$ /Users/azyablov/py/ISIS_SRexplorer/main.py -g -s sre1 -d sre5
Path from sre1 (14001) to sre5 (14005): [<Name: sre1, SystemID: 0100.0000.0001>, <Name: sre2, SystemID: 0100.0000.0002>, <Name: sre5, SystemID: 0100.0000.0005>]

On the picture below graph is reflecting network topology, directional adjacencies, Node- and Adj-SIDs, interface names and highlight requested SPF path between nodes sre1 -> sre5.

Getting Adjacency Matrix and SFP Path

$ /Users/azyablov/py/ISIS_SRexplorer/main.py -a -s sre1 -d sre5
Adjacency matrix:
                                        | sre1 (14001) -> sre2 (14002): 524287    | sre1 (14001) -> sre3 (14003): 524285    |                                         |                                         | 

sre2 (14002) -> sre1 (14001): 30012     |                                         | sre2 (14002) -> sre3 (14003): 524286    |                                         | sre2 (14002) -> sre5 (14005): 524287    | 

sre3 (14003) -> sre1 (14001): 524287    | sre3 (14003) -> sre2 (14002): 524286    |                                         | sre3 (14003) -> sre4 (14004): 524285    |                                         | 

                                        |                                         | sre4 (14004) -> sre3 (14003): 524286    |                                         | sre4 (14004) -> sre5 (14005): 524287    | 

                                        | sre5 (14005) -> sre2 (14002): 524287    |                                         | sre5 (14005) -> sre4 (14004): 524285    |                                         | 

Path from sre1 (14001) to sre5 (14005): [<Name: sre1, SystemID: 0100.0000.0001>, <Name: sre2, SystemID: 0100.0000.0002>, <Name: sre5, SystemID: 0100.0000.0005>]

Configuration File

Configuration is quite straightforward. Root node is mandatory since used extract key parameters like SRGB. If username, password and / or port aren't provided in the file, then it could be specified via CLI parameter as default value. Default value for NETCONF port is 830.

root:
  host: 127.0.0.1
  user: 'netconf'
  pwd: 'nokia123'
  netconf_port: 1831
nodes:
# sre2
  - host: 127.0.0.1
    user: 'netconf'
    pwd: 'nokia123'
    netconf_port: 1832
# sre3
  - host: 127.0.0.1
    user: 'netconf'
    pwd: 'nokia123'
    netconf_port: 1833
# sre4
  - host: 127.0.0.1
    user: 'netconf'
    pwd: 'nokia123'
    netconf_port: 1834
# sre5
  - host: 127.0.0.1
    user: 'netconf'
    pwd: 'nokia123'
    netconf_port: 1835