show cdp neighbor is it only way, fastest way, to ID lines?

inscom.brigadeinscom.brigade I like soupMember Posts: 400 ■■■□□□□□□□
I have to find what is on the other end of the line in my own network. Is show cdp neighbor the fastest and only way?

I do not have any topology map that is what I am making, I can not physicaly trace it either; the run is to long.

I have lots of lines to do the id and write the desctiption, and wonder if any thing that you know might go quicker.

thank you


  • networker050184networker050184 Went to the dark side.... Mod Posts: 11,962 Mod
    Its the fastest way via the CLI. You could also look at MAC/IP addresses as well but that would be a little slower going. Possibly you have ISIS configured, but that's unlikely.

    There are also programs that will do this for you via SNMP.
    An expert is a man who has made all the mistakes which can be made.
  • RouteMyPacketRouteMyPacket Senior Member Member Posts: 1,104
    CDP is how I discovered my trunk links/fiber runs at all of my sites. It wasn't fast but it's effective and that for me is what matters.

    Cisco Network Assistant would literally provide you with a topology layout showing everything you need to know. You would need to configure devices though so you would need SNMP and IP information
    Modularity and Design Simplicity:

    Think of the 2:00 a.m. test—if you were awakened in the
    middle of the night because of a network problem and had to figure out the
    traffic flows in your network while you were half asleep, could you do it?
  • EildorEildor Senior Member Member Posts: 444
    Correct me if I am wrong but I don't think you need to configure SNMP for CNA... you would need to enable HTTP or HTTPS though.
  • inscom.brigadeinscom.brigade I like soup Member Posts: 400 ■■■□□□□□□□
    I am not having much luck, if i do a show cdp neighbor, i get 6 connected routes.
    if i do a show interface status, it shows uncountable number of connected lines.
    How do i trace the other connected lines?
  • EildorEildor Senior Member Member Posts: 444
    Sure those aren't links connecting to end devices? Look at the configuration on the interface.
  • azaghulazaghul Senior Member Member Posts: 569 ■■■■□□□□□□
    I had to do something similar for one of our smaller Data Centres last year, map the topology for everything including end devices, took 3 weeks of chasing cables to just build the spreadsheet. Sometimes an eyeball is the only thing that works. Thankfully all cables are labelled to make it managable, otherwise I'd still be at it.

    CDP only gets you so far being a Cisco proprietary protocol, so if you're not connecting to a Cisco device (and a couple of others who have licensed it) or if CDP is not turned on, its a slow, tedious task.

    I'm currently documenting our minor sites (1 router & up to 3 switches usually), thankfully all Cisco kit, and now they want servers added. Just waiting on the IP address or hostname for each device, then use show arp and show mac-address-table.

    I'd rather be doing builds, or almost anything other than documentation, but I also like to get paid.:D
  • inscom.brigadeinscom.brigade I like soup Member Posts: 400 ■■■□□□□□□□
    this is a new data center build, it is going up fast, it is like a reality TV show but for real!

    these are on nexus 7k & 5k

    On 7k A1

    I did a:

    int e 101/1/2
    (config-if)show cdp nei detail

    I think it says that port is connected to

    7k A2 port e1/5

    but I can not ping it so?

    It is my 3rd day on the job, I was at the data center yesterday, but now i am at the Cube Farm.
    I cannot do much at this time because I am waiting on congress to give the ok to give me Local admin rights on my PC. I am lucky I was able to get my portable terminal emulator to work. the told me that if I pluged in my flash drive that it would become encypted.
  • tech_usertech_user Junior Member Member Posts: 5 ■□□□□□□□□□
    you could use tcl or eem script to find cdp neighbors and you could also get some portion of the outputs
  • inscom.brigadeinscom.brigade I like soup Member Posts: 400 ■■■□□□□□□□
    guess I am going to be using the cdp neighbor command, show interface status, maybe get in some iterfaces and use the show cdp neighbors detail.
    built a spread sheet and present it to my supervisor, to accept the changes.
  • EildorEildor Senior Member Member Posts: 444
    I don't have any real-world experience so I'm not in a position to give advice.

    But I guess it would be a good idea to think everything through thoroughly first to avoid going back and doing it all over again.

    What kind of information are you going to be recording?

    As for the interface you can't ping, have you tried telnet/SSH into it?
  • inscom.brigadeinscom.brigade I like soup Member Posts: 400 ■■■□□□□□□□
    Oh yeah I can ssh into all the devices. I got more information I got a real rough drawing 2, 7k nexus, 2, 5k nexus, and 12, 2k nexus. We just stated this new data center, it is a new building. the cable/wire guys are still getting in wires. we /I have also been their tonight till 12midnight. tomorow I get to go again for a 12 hour shift so this is cool. I been given the first draft spread sheet asignment to build the topology. I learned some new NEXUS show commands, Probably not ok to post them public though. I just get home I wil post some photos soon. My fingers so sore from getting some stuff from the old DATA center, I took down 3 cisco 6500's full of copper and fiber.

    Everyone has their own stuff I am just on the crew with routers and switches, dun't even have to deal with ASA we have security team,VM team, SAN team, but I ran a wire today for a cisco ironport to a 4509E, dang this job is so fing cool!! my first week, can you tell. haha!
  • EildorEildor Senior Member Member Posts: 444
    Sounds very exciting. Lucky you!
  • ThunderPipeThunderPipe Senior Member Member Posts: 120
    I would log into the Nexus, grab some paper and a pen, do a "show cdp nei", and get to drawing it by hand the hard way. After you've got all of those devices listed (IP, port, name, you dont have to find it again), log into each one, one at a time, and do the same thing. It's a long boring process. But you'll learn the network better and have full control over the design of the drawing. I'm surprised SNMP wasn't enable to begin with.
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