Have you ever been on a Data ONTAP system without a clear idea
of how the physical network is connected, and wish you could interrogate your
network to try and find out? If so, CDP – the Cisco Discovery Protocol – might be the help you’re
looking for. This can be very useful on systems with large or complex Ethernet
configurations.
Once CDP is enabled in Data ONTAP, your Cisco switches will
become aware of which NetApp systems are cabled to which ports. It wil know
both the source port (on the NetApp) and the destination port (on the Cisco
switch).
CDP has been available in Netapp Data ONTAP since version 7.3.3,
and is supported in both 7-mode and cDOT, and it’s simply enabled with an option command.
To enable CDP in
7-mode:
options cdpd.enable on
To enable CDP in cDOT:
node run -node * options cdpd.enable on
NOTE that the command
is cdpd.enable, not cdp.enable
The nice thing about
NetApp’s CDP implementation is that it is bi-directional. That means you can
query CDP from either the Cisco switch or the NetApp controller and see
information — meaning you don’t have to rely on a network administrator to
provide you the information!
To view CDP information from 7-mode Data ONTAP, you would use the cdpd show-neighbors command.
Here’s some sample
output:
nas1> cdpd show-neighbors
Local
Remote Remote Remote Hold
Remote
Port
Device Interface Platform Time
Capability
------ --------------- ----------------------
---------------- ----- ----------
e0M
charles e0M FAS3170 146
H
e0M
nane-cat4948-sw GigabitEthernet1/8
cisco WS-C4948-. 174 RSI
e3a
nane-nx5010-sw. Ethernet1/4
N5K-C5010P-BF 173 SI
e4a
nane-nx5010-sw. Ethernet1/14
N5K-C5010P-BF 177 SI
Note that we can see that Filer’s HA partner, charles, is in the output.
Here we can see that e0M is cabled to port Giga1/8 on nane-cat4948, whereas e3a and e4a are cabled to Eth1/4 andEth1/14 on nane-nx5010-sw respectively.
This is incredibly
useful information if you’re ever trying to track down how a system is cabled!
To view CDP information from clustered Data ONTAP, use the run -node nodeName cdpd show-neighbors command.
The output is the same
format as in 7-mode:
dot83cm::> node run -node local cdpd
show-neighbors
Local
Remote Remote Remote Hold
Remote
Port
Device Interface Platform Time
Capability
------ --------------- ----------------------
---------------- ----- ----------
e6a
nane-nx5010-sw. Ethernet1/12
N5K-C5010P-BF 145
SI
e6b
nane-nx5010-sw. Ethernet1/5
N5K-C5010P-BF 145 SI
e4a
dot83cm-01 e4a FAS3240 161
H
e4b
dot83cm-01 e4b FAS3240 161
H
e0a
nane-cat4948-s. GigabitEthernet1/9
cisco WS-C4948-. 168 RSI
In this case, e6a and e6b go to the same
switch, with e4a and e4b going to the
other node in this HA pair — that’s my switchless cluster interconnect. e0a goes to an older
Catalyst switch.
To view CDP information from Cisco IOS or NX-OS, use the show cdp neighbors command.
Sample output:
nane-nx5010-sw# show cdp neighbors
Capability Codes: R - Router, T - Trans-Bridge, B
- Source-Route-Bridge
S - Switch, H - Host, I - IGMP, r - Repeater,
V - VoIP-Phone, D - Remotely-Managed-Device,
s - Supports-STP-Dispute, M - Two-port Mac Relay
Device ID Local Intrfce Hldtme
Capability Platform Port ID
US-WLM-LS02 mgmt0 124 R S I
WS-C6509 Gig5/1
nane-cat4948-sw Eth1/2 179 R S I
WS-C4948-10GE Ten1/49
dot83cm-01 Eth1/3 163 H
FAS3240 e6b
mystic Eth1/4 127 H
FAS3170 e3a
dot83cm-02 Eth1/5 158 H
FAS3240 e6b
In IOS/NX-OS, you may wish to run show cdp neighbors detail to gather more information.
To view CDP information using the vSphere/VI Client: Connect to the vCenter
Server/Virtual Center or ESX host using the vSphere/VI Client.
·
Select the ESX host in
the Inventory.
·
Click the Configuration tab.
·
Click Networking.
·
Click the Info icon to
the right of the vSwitch, under Properties.
More detailed
information about the output of CDP commands can be found in the relevant Ontap Network Management Guide, Cisco and VMware documentation.
Hope you don’t have to
trace the network cables the hard way anymore!