CLI L2 Data Plugin

CLI L2 Data Plugin can produce diagrams based on OSI model layer 2 information, hence the name “layer 2”. This plugin builds network diagrams with relationships and nodes using CDP and LLDP protocols neighbors information. In addition, adding L1/L2 related data to diagram elements.

CLI L2 Data Plugin uses TTP templates to parse show commands output and transform them in Python dictionary structure. That structure processed further to build a dictionary compatible with N2G’s diagram plugins from_dict method. That method used to populate diagrams with devices and links information.

In addition to parsing relationships for CDP and LLDP protocols, L2 Data Plugin can help to manipulate diagrams by combining links based on certain criteria, adding additional information to elements meta data and adding unknown (to CDP and LLDP) but connected nodes to diagram.

Features Supported

Features Support Matrix

Platform Name	CDP peers	LLDP peers	interface config	interface state	LAG links	links grouping	node facts	Add all connected	Combine peers
cisco_ios	YES	YES	YES	YES	YES	YES	YES	YES	YES
cisco_xr	YES	YES	YES	YES	YES	YES	—	YES	YES
cisco_nxos	YES	YES	YES	YES	YES	YES	YES	YES	YES
huawei	—	YES	YES	—	YES	YES	YES	—	YES
juniper	—	YES	YES	YES	YES	YES	—	YES	YES

Features Description

CDP peers - adds links and nodes for CDP neighbors
LLDP peers - adds links and nodes for LLDP neighbors
interface config - adds interfaces configuration to links data
interface state - add links state information to links data
LAG links - combines links based on LAG membership
links grouping - groups links between nodes
node facts - adds information to nodes for vlans configuration
Add all connected - add nodes for connected interfaces that has no peers via CDP or LLDP
Combine peers - groups CDP/LLDP peers behind same port by adding “L2” node

Required Commands output

cisco_xr:

show cdp neighbor details and/or show lldp neighbor details - mandatory
show lldp - optional, to extract local hostname
show running-configuration interface - optional, used for LAG and interfaces config
show interfaces - optional, used for interfaces state and to add all connected nodes

cisco_ios, cisco_nxos:

show cdp neighbor details and/or show lldp neighbor details - mandatory
show running-configuration - optional, used for LAG and interfaces config
show interface - optional, used for interfaces state and to add all connected nodes

huawei:

display lldp neighbor details - mandatory
display current-configuration interface - optional, used for LAG and interfaces config
display interface - optional, used for interfaces state and to add all connected nodes

juniper:

show lldp local-information - to extract local hostname
show lldp neighbors - to extract LLDP neighbors
show configuration interfaces | display set - to extract interfaces configuration and LAG details
show interfaces detail - to extract interfaces state to add all connected devices

Sample Usage

Code to populate yEd diagram object with CDP and LLDP sourced nodes and links:

from N2G import cli_l2_data, yed_diagram

data = {"cisco_ios": ['''
switch-1#show cdp neighbors detail
-------------------------
Device ID: switch-2
Entry address(es):
  IP address: 10.2.2.2
Platform: cisco WS-C6509,  Capabilities: Router Switch IGMP
Interface: GigabitEthernet4/6,  Port ID (outgoing port): GigabitEthernet1/5

-------------------------
Device ID: switch-3
Entry address(es):
  IP address: 10.3.3.3
Platform: cisco WS-C3560-48TS,  Capabilities: Switch IGMP
Interface: GigabitEthernet1/1,  Port ID (outgoing port): GigabitEthernet0/1

-------------------------
Device ID: switch-4
Entry address(es):
  IP address: 10.4.4.4
Platform: cisco WS-C3560-48TS,  Capabilities: Switch IGMP
Interface: GigabitEthernet1/2,  Port ID (outgoing port): GigabitEthernet0/10

switch-1#show run
interface GigabitEthernet4/6
 description switch-2: access
 switchport
 switchport access vlan 2150
 switchport mode access
 spanning-tree portfast edge
!
interface GigabitEthernet1/1
 description switch-3:Gi0/1
 switchport
 switchport trunk allowed vlan 1771,1887
 switchport mode trunk
 mtu 9216
!
interface GigabitEthernet1/2
 description SW4 Routing Peering
 vrf forwarding VRF1
 ip address 10.0.0.1 255.255.255.0
    ''',
    '''
switch-2#show cdp neighbors detail
-------------------------
Device ID: switch-1
Entry address(es):
  IP address: 10.1.1.1
Platform: cisco WS-C6509,  Capabilities: Router Switch IGMP
Interface: GigabitEthernet1/5,  Port ID (outgoing port): GigabitEthernet4/6

switch-2#show run
interface GigabitEthernet1/5
 description switch-1: access
 switchport
 switchport access vlan 2150
 switchport mode access
 spanning-tree portfast edge
    ''']
    }

config = {
    "add_interfaces_data": True,
    "group_links": False,
    "add_lag": False,
    "add_all_connected": False,
    "combine_peers": False,
    "platforms": ["_all_"]
}

drawing_l2 = yed_diagram()
drawer = cli_l2_data(drawing_l2, **config)
drawer.work(data)
drawer.drawing.dump_file()

API Reference

class N2G.plugins.data.cli_l2_data.cli_l2_data(drawing, ttp_vars=None, add_interfaces_data=True, group_links=False, add_lag=False, add_all_connected=False, combine_peers=False, skip_lag=True, platforms=None)

Class to instantiate L2 (layer two) data plugin to process CDP and LLDP neighbors together with devices’ running configuration and state and produce diagram out of it.

Parameters

drawing – (obj) N2G drawing object instantiated using drawing module e.g. yed_diagram or drawio_diagram
ttp_vars – (dict) dictionary to use as TTP parser object template variables
platforms – (list) - list of platform names to process e.g. cisco_ios, cisco_xr etc, default is _all_
add_interfaces_data – (bool) default True, add interfaces configuration and state data to links
group_links – (bool) default False, group links between nodes
add_lag – (bool) default False, add LAG/MLAG links to diagram
add_all_connected – (bool) default False, add all nodes connected to devices based on interfaces state
combine_peers` – (bool) default False, combine CDP/LLDP peers behind same interface by adding L2 node
skip_lag – (bool) default True, skip CDP peers for LAG, some platforms send CDP/LLDP PDU from LAG ports

work(data)

Method to parse text data and add nodes and links to N2G drawing.

Parameters: data – (dict or str) dictionary or OS path string to directories with text files

If data is dictionary, keys must correspond to “Platform” column in Features Supported section table, values are lists of text items to process.

Data dictionary sample:

data = {
    "cisco_ios" : ["h1", "h2"],
    "cisco_ios": ["h3", "h4"],
    "cisco_nxos": ["h5", "h6"],
    ...etc...
}

Where hX devices show commands output.

If data is an OS path directory string, child directories’ names must correspond to Platform column in Features Supported section table. Each child directory should contain text files with show commands output for each device, names of files are arbitrary, but output should contain device prompt to extract device hostname.

Directories structure sample:

├───folder_with_data
    ├───cisco_ios
    │       switch1.txt
    │       switch2.txt
    └───cisco_nxos
            nxos_switch_1.txt
            nxos_switch_2.txt

To point N2G to above location data attribute string can be /var/data/n2g/folder_with_data/