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 $c_if = $cdp->c_if();
my $c_ip = $cdp->c_ip();
my $c_port = $cdp->c_port();
foreach my $cdp_key (keys %$c_ip){
my $iid = $c_if->{$cdp_key};
my $port = $interfaces->{$iid};
my $neighbor = $c_ip->{$cdp_key};
my $neighbor_port = $c_port->{$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 in Cisco and
some HP devices.
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
MIBs can be found at
ftp://ftp.cisco.com/pub/mibs/v2/v2.tar.gz
GLOBAL METHODS¶
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_id()
- 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->c_capabilities()
- Returns Device Functional Capabilities. Results are munged
into an ascii binary string, 7 digits long, MSB. Each digit represents a
bit from the table below.
From
<http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm#18843>:
(Bit) - Description
- (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 "martin -at- lorensen.dk" for a pointer to
this information.
("cdpCacheCapabilities")
- $cdp->c_domain()
- Returns remote VTP Management Domain as defined in
"CISCO-VTP-MIB::managementDomainName"
("cdpCacheVTPMgmtDomain")
- $cdp->c_duplex()
- Returns the port duplex status from remote devices.
("cdpCacheDuplex")
- $cdp->c_id()
- Returns remote device id string
("cdpCacheDeviceId")
- $cdp->c_if()
- Returns the mapping to the SNMP Interface Table.
Note that a lot devices don't implement $cdp-> c_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 $c_index = $device->c_index();
return $c_index if defined $c_index;
# if not, let's fake it
my $c_ip = $device->c_ip();
my %c_if
foreach my $key (keys %$c_ip){
$iid = $key;
## Truncate off .1 from cdp response
$iid =~ s/\.\d+$//;
$c_if{$key} = $iid;
}
return \%c_if;
- $cdp->c_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->
c_if() instead.
See c_if() entry.
("cdpCacheIfIndex")
- $cdp->c_ip()
- If $cdp->c_proto() is supported, returns remote
IPV4 address only. Otherwise it will return all addresses.
("cdpCacheAddress")
- $cdp->c_addr()
- Returns remote address
("cdpCacheAddress")
- $cdp->c_platform()
- Returns remote platform id
("cdpCachePlatform")
- $cdp->c_port()
- Returns remote port ID
("cdpDevicePort")
- $cdp->c_proto()
- Returns remote address type received. Usually IP.
("cdpCacheAddressType")
- $cdp->c_ver()
- Returns remote hardware version
("cdpCacheVersion")
- $cdp->c_vlan()
- Returns the remote interface native VLAN.
("cdpCacheNativeVLAN")
- $cdp->c_power()
- Returns the amount of power consumed by remote device in
milliwatts munged for decimal placement.
("cdpCachePowerConsumption")
Data Munging Callback Subroutines¶
- $cdp->munge_power()
- Inserts a decimal at the proper location.
