I understand we able to verify links that created on the equipment. Protocols lldp, lsp, ospf can provide those information but what is the best command that able to show link between neighbors? I try to understand how link is created with the neighbours and at the same time able to provide local and neighbour links information. Is there any specific command that able to provide local and neighbor info that created the link (source port/ip/mac address/destn port/ip/mac address) . I have lookup example of show lldp neighbor and show ospf neighbour
Local Interface Parent Interface Chassis Id Port info System Name
xe-3/0/4.0 ae31.0 b0:c6:9a:63:80:40 xe-0/0/0.0 host.jnpr.net
xe-3/0/5.0 ae31.0 b0:c6:9a:63:80:40 xe-0/0/1.0 host.jnpr.net
Address Interface State ID Pri Dead
10.1.12.2 so-0/0/0.0 Full 10.0.0.2 128 39
10.1.15.2 so-0/0/1.0 Full 10.0.0.5 128 39
10.1.13.2 so-0/0/2.0 Full 10.0.0.3 128 33
show lldp neighbr does not show interface/mac address of neighbor device.
What is the initial info require to create a link between 2 devices?
Im sorry ..noob in this but learning from you guyz and hope you could enlighten me. Thanks you for you support.
OSPF is layer 3 by default so does show the router-id ip address in the return. But generally this will not be active on all links only layer 3 connections out of a device so is less comprehensive for building topologies.
Steve Puluka BSEET - Juniper Ambassador IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP) http://puluka.com/home
There are LLDP show commands providing information about local device and providing more details about neighbor on specific interface. The support of the commands and their output is platform and version specific.
device > show lldp neighbors interface <interface-name>
device > show lldp local-information
You can more information and example output in command reference in TechLibrary:
You can capture the control traffic on specific device interface if needed to further decode more information. You can capture only traffic destined to control plane (Routing Engine - RE). Use command:
Option layer2-headers will show you also source and destination MAC address. The keyword matching can narrow captured traffic (syntax is similar to tcpdump). There is also hidden option to write output to PCAP file ( write-file <file-name>) - one can analyze output later in Wireshark for example.
One example - capture the OSPFv2 traffic on interface ge-0/0/1.0 :