s vermill wrote: > > J. Johnson wrote: > > > > Is there a CDP config option that will tell a cisco box to > keep > > a log of CDP > > activity? If so, how would an administrator access it? It > > might be nice > > to see a history of when neighbors come up or go down, or when > > they change > > settings.
There doesn't seem to be any such thing. It sure would be useful. Send a message to Cisco to ask for an enhancement! The debug cdp command tells you some stuff but it's hard to parse and tells you too much. It could be dangerous to enable it, since it spews so much output every 60 seconds at least (more if it's receiving CDP messages too). I think Scott just mentioned it because he discovered the debug cdp ip command, which is indeed strange. We all know that CDP is a data-link-layer protocol. Scott, I think it must be useful only when you're using on-demand routing (ODR), which uses CDP, I guess. See here for more info: http://www.cisco.com/warp/public/105/39.html _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > > > James > > > > > > I found this to be pretty interesting: > > ____________________________ > debug cdp > Use the debug cdp EXEC command to enable debugging of Cisco > Discovery Protocol (CDP). The no form of this command disables > debugging output. > > [no] debug cdp {packets | adjacency | events} > Syntax Description > > packets > Enables packet-related debugging output. > > adjacency > Enables adjacency-related debugging output. > > events > Enables output related to error messages, such as detecting a > bad checksum. > > > > Usage Guidelines > Use debug cdp commands to display information about CDP packet > activity, activity between CDP neighbors, and various CDP events. > > Sample Display > The following is sample output from debug cdp packets, debug > cdp adjacency, and debug cdp events commands: > > Router# debug cdp packets > CDP packet info debugging is on > Router# debug cdp adjacency > CDP neighbor info debugging is on > Router# debug cdp events > CDP events debugging is on > CDP-PA: Packet sent out on Ethernet0 > CDP-PA: Packet received from gray.cisco.com on interface > Ethernet0 > CDP-AD: Deleted table entry for violet.cisco.com, interface > Ethernet0 > CDP-AD: Interface Ethernet2 coming up > CDP-EV: Encapsulation on interface Serial2 failed > debug cdp ip > Use the debug cdp ip EXEC command to enable debug output for > the IP routing information that is carried and processed by the > Cisco Discovery Protocol (CDP). The no form of this command > disables debugging output. > > > [no] debug cdp ip > Usage Guidelines > CDP is a media- and protocol-independent device-discovery > protocol that runs on all Cisco routers. > > You can use the debug cdp ip command to determine the IP > network prefixes CDP is advertising and whether CDP is > correctly receiving this information from neighboring routers. > > Use the debug cdp ip command with the debug ip routing command > to debug problems that occur when on-demand routing (ODR) > routes are not installed in the routing table at a hub router. > You can also use the debug cdp ip command with the debug cdp > packet and debug cdp adjacency commands along with > encapsulation-specific debug commands to debug problems that > occur in the receipt of CDP IP information. > > Sample Display > The following is sample output from the debug cdp ip command. > This example shows the transmission of IP-specific information > in a CDP update. In this case, three network prefixes are being > transmitted, each with a different network mask. > > Router# debug cdp ip > CDP-IP: Writing prefix 172.1.69.232.112/28 > CDP-IP: Writing prefix 172.19.89.0/24 > CDP-IP: Writing prefix 11.0.0.0/8 > In addition to these messages, you might see the following > messages: > > This message indicates that CDP is attempting to install the > prefix 172.1.1.0/24 into the IP routing table: > CDP-IP: Updating prefix 172.1.1.0/24 in routing table > This message indicates a protocol error occurred during an > attempt to decode an incoming CDP packet: > CDP-IP: IP TLV length (3) invalid > This message indicates the receipt of the IP prefix > 172.1.1.0/24 from a CDP neighbor connected via the Ethernet > interface 0/0. The neighbor's IP address is 10.0.01. > CDP-IP: Reading prefix 172.1.1.0/24 source 10.0.0.1 via > Ethernet0/0 > Related Commands > debug cdp adjacency > debug cdp packet > debug ip routing > > ________________________________ > > What the heck was all that stuff about exchanging prefixes via > CDP? > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61524&t=61471 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
