Troubleshooting steps if the Layer 2 network map is not discovered

Troubleshooting steps if the Layer 2 network map is not discovered

If your map is not discovered after entering the details in Discover Layer 2 Map, or if you see this message "Device mapping does not exist for this map.":
  • Check if the device is reachable through SNMP. 
  • Check if your seed device satisfies the following conditions.
    The seed device should 
    1. either be a core router or an L3 switch in your network. 
    2. have SNMP enabled; only then it can be queried to draw links automatically. 
    3. have ipForwarding set to 1 for the OID - .1.3.6.1.2.1.4.1.0. (identified by querying the OID - 1.3.6.1.2.1.4.20.1.1)
    4. have two or more interfaces. 
  • Select suitable Discovery Mechanisms from the drop-down list.

Type of device
Discovery mechanism
Cisco device
CDP
Layer 3 switches and routers
ARP
Switches
FDB
Wired LAN ethernet
LLDB
Routers and switches
IP route

List of OIDs used for Layer2 Discovery 
BRIDGE-MIB 
  1. .1.3.6.1.2.1.17.4.3.1.1 
  2. .1.3.6.1.2.1.17.4.3.1.2 
  3. .1.3.6.1.2.1.17.4.3.1.3 
  4. .1.3.6.1.2.1.17.1.4.1.1
  5. .1.3.6.1.2.1.17.1.4.1.2 
RFC1213.MIB (NetToMediaTable) 
  1. .1.3.6.1.2.1.4.22.1.1 
  2. .1.3.6.1.2.1.4.22.1.2 
  3. .1.3.6.1.2.1.4.22.1.3 
  4. .1.3.6.1.2.1.4.22.1.4
RFC1213 (IPRouteTable) 
  1. .1.3.6.1.2.1.4.21.1.1 
  2. .1.3.6.1.2.1.4.21.1.2 
  3. .1.3.6.1.2.1.4.21.1.7 
  4. .1.3.6.1.2.1.4.21.1.8 
  5. .1.3.6.1.2.1.4.21.1.11
CISCO-CDP.MIB (CDP) - MIB files attached
  1. .1.3.6.1.4.1.9.9.23.1.2.1.1.4 
  2. .1.3.6.1.4.1.9.9.23.1.2.1.1.7 
  3. .1.3.6.1.4.1.9.9.23.1.2.1.1.9 
LLDP.MIB(LLDP) - MIB files attached
  1. .1.0.8802.1.1.2.1.4.1.1.4
  2. .1.0.8802.1.1.2.1.4.1.1.5
  3. .1.0.8802.1.1.2.1.4.1.1.8
  4. .1.0.8802.1.1.2.1.4.1.1.9
  5. .1.0.8802.1.1.2.1.4.1.1.12
  6. .1.0.8802.1.1.2.1.4.2.1.2
  7. .1.0.8802.1.1.2.1.4.2.1.3
IF-MIB 
  1. ifIndex - .1.3.6.1.2.1.2.2.1.1
  2. ifName - .1.3.6.1.2.1.31.1.1.1.1
Router Discovery Algorithm
  1. "ipForwarding" of the device must be set to 1 - .1.3.6.1.2.1.4.1.0
  2. The object must have two or more interfaces. - .1.3.6.1.2.1.4.20.1.1
Switch Discovery Algorithm
  1. Bridge MIB OIDs should respond.

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