--- name: "SNMP::Info::CDP" section: "3pm" platform: "linux" package: "libsnmp-info-perl" version: "3.972002-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/SNMP::Info::CDP" --- # SNMP::Info::CDP(3pm) SNMP Interface to Cisco Discovery Protocol (CDP) using SNMP ## NAME SNMP::Info::CDP - SNMP Interface to Cisco Discovery Protocol (CDP) using SNMP ## AUTHOR Max Baker ## SYNOPSIS ``` my $cdp = new SNMP::Info ( AutoSpecify => 1, Debug => 1, DestHost => 'router', Community => 'public', Version => 2 ); my $class = $cdp->class(); print " Using device sub class : $class\n"; $hascdp = $cdp->hasCDP() ? 'yes' : 'no'; # Print out a map of device ports with CDP neighbors: my $interfaces = $cdp->interfaces(); my $cdp_if = $cdp->cdp_if(); my $cdp_ip = $cdp->cdp_ip(); my $cdp_port = $cdp->cdp_port(); foreach my $cdp_key (keys %$cdp_ip){ my $iid = $cdp_if->{$cdp_key}; my $port = $interfaces->{$iid}; my $neighbor = $cdp_ip->{$cdp_key}; my $neighbor_port = $cdp_port->{$cdp_key}; print "Port : $port connected to $neighbor / $neighbor_port\n"; } ``` ## DESCRIPTION SNMP::Info::CDP is a subclass of SNMP::Info that provides an object oriented interface to CDP information through SNMP. CDP is a Layer 2 protocol that supplies topology information of devices that also speak CDP, mostly switches and routers. CDP is implemented by Cisco and several other vendors. Create or use a device subclass that inherits this class. Do not use directly. Each device implements a subset of the global and cache entries. Check the return value to see if that data is held by the device. ### Inherited Classes None. ### Required MIBs - *CISCO-CDP-MIB* ## GLOBALS These are methods that return scalar values from SNMP - $cdp-\>**hasCDP()** Is CDP is active in this device? Accounts for SNMP version 1 devices which may have CDP but not **cdp\_run()** - $cdp-\>**cdp\_run()** Is CDP enabled on this device? Note that a lot of Cisco devices that implement CDP don't implement this value. @#%$! (`"cdpGlobalRun"`) - $cdp-\>**cdp\_interval()** Interval in seconds at which CDP messages are generated. (`"cdpGlobalMessageInterval"`) - $cdp-\>**cdp\_holdtime()** Time in seconds that CDP messages are kept. (`"cdpGlobalHoldTime"`) - $cdp-\>**cdp\_gid()** Returns CDP device ID. This is the device id broadcast via CDP to other devices, and is what is retrieved from remote devices with `$cdp`-\>**id()**. (`"cdpGlobalDeviceId"`) ## TABLE METHODS These are methods that return tables of information in the form of a reference to a hash. ### CDP CACHE ENTRIES - $cdp-\>**cdp\_capabilities()** Returns Device Functional Capabilities. Results are munged into an ascii binary string, MSB. Each digit represents a bit from the table below from the CDP Capabilities Mapping to Smartport Type table within the Cisco Small Business 200 Series Smart Switch Administration Guide, \: (Bit) - Description - (0x400) - Two-Port MAC Relay. - (0x200) - CAST Phone Port / CVTA / Supports-STP-Dispute depending upon platform. - (0x100) - Remotely-Managed Device. - (0x80) - VoIP Phone. - (0x40) - Provides level 1 functionality. - (0x20) - The bridge or switch does not forward IGMP Report packets on non router ports. - (0x10) - Sends and receives packets for at least one network layer protocol. If the device is routing the protocol, this bit should not be set. - (0x08) - Performs level 2 switching. The difference between this bit and bit 0x02 is that a switch does not run the Spanning-Tree Protocol. This device is assumed to be deployed in a physical loop-free topology. - (0x04) - Performs level 2 source-route bridging. A source-route bridge would set both this bit and bit 0x02. - (0x02) - Performs level 2 transparent bridging. - (0x01) - Performs level 3 routing for at least one network layer protocol. Thanks to Martin Lorensen for a pointer to the original information and CPAN user Alex for updates. (`"cdpCacheCapabilities"`) - $cdp-\>**cdp\_domain()** Returns remote VTP Management Domain as defined in `"CISCO-VTP-MIB::managementDomainName"` (`"cdpCacheVTPMgmtDomain"`) - $cdp-\>**cdp\_duplex()** Returns the port duplex status from remote devices. (`"cdpCacheDuplex"`) - $cdp-\>**cdp\_id()** Returns remote device id string (`"cdpCacheDeviceId"`) - $cdp-\>**cdp\_if()** Returns the mapping to the SNMP Interface Table. Note that a lot devices don't implement `$cdp`-\>**cdp\_index()**, So if it isn't around, we fake it. In order to map the cdp table entry back to the **interfaces()** entry, we truncate the last number off of it : ``` # it exists, yay. my $cdp_index = $device->cdp_index(); return $cdp_index if defined $cdp_index; # if not, let's fake it my $cdp_ip = $device->cdp_ip(); my %cdp_if foreach my $key (keys %$cdp_ip){ $iid = $key; ## Truncate off .1 from cdp response $iid =~ s/\.\d+$//; $cdp_if{$key} = $iid; } return \%cdp_if; ``` - $cdp-\>**cdp\_index()** Returns the mapping to the SNMP2 Interface table for CDP Cache Entries. Most devices don't implement this, so you probably want to use `$cdp`-\>**cdp\_if()** instead. See **cdp\_if()** entry. (`"cdpCacheIfIndex"`) - $cdp-\>**cdp\_ip()** If `$cdp`-\>**cdp\_proto()** is supported, returns remote IPV4 address only. Otherwise it will return all addresses. (`"cdpCacheAddress"`) - $cdp-\>**cdp\_addr()** Returns remote address (`"cdpCacheAddress"`) - $cdp-\>**cdp\_platform()** Returns remote platform id (`"cdpCachePlatform"`) - $cdp-\>**cdp\_port()** Returns remote Port-ID. Most of the time this is a string with the port name, but this is not guaranteed to be so. (`"cdpCacheDevicePort"`) - $cdp-\>**cdp\_proto()** Returns remote address type received. Usually IP. (`"cdpCacheAddressType"`) - $cdp-\>**cdp\_ver()** Returns remote hardware version (`"cdpCacheVersion"`) - $cdp-\>**cdp\_vlan()** Returns the remote interface native VLAN. (`"cdpCacheNativeVLAN"`) - $cdp-\>**cdp\_power()** Returns the amount of power consumed by remote device in milliwatts munged for decimal placement. (`"cdpCachePowerConsumption"`) - $cdp-\>**cdp\_cap()** Returns hash of arrays with each array containing the system capabilities supported by the remote system. Possible elements in the array are `"Router"`, `"Trans-Bridge"`, `"Source-Route-Bridge"`, `"Switch"`, `"Host"`, `"IGMP"`, `"Repeater"`, `"VoIP-Phone"`, `"Remotely-Managed-Device"`, `"Supports-STP-Dispute"`, and `"Two-port Mac Relay"`. ## Data Munging Callback Subroutines - $cdp-\>**munge\_power()** Inserts a decimal at the proper location.