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--- cisco_discovery_protocol_cdp [2024/01/19 14:41] – [Some CDP Facts] walkeradmin
+++ cisco_discovery_protocol_cdp [2024/01/19 14:56] (current) – [CDP Neighbors Detail] walkeradmin
@@ Line 26: / Line 26: @@
 When a devices receives a CDP message from a neighbouring device, it adds an entry for that device in its CDP Neighbour table.
-When a devices receives a CDP message from a neighboring device, it adds an entry for that device in its CDP Neighbour table.
 By default, the CDP Holdtime is 180 seconds, so if a neighbour isn't heard from after 180s, it is removed from the CDP Neighbour table.
@@ Line 97: / Line 95: @@
   Rack4Control     Gig 0/2           152              S I   WS-C2960- Fas 0/2
 \\
+Look at the diagram below, this is what we have physically:
+\\
+\\
+{{ ::cdp_001.png?900 |}}
+\\
+Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
+\\
+Switch           Gig 0/1           135              S I   WS-C2960- Fas 0/1
+\\
+Rack4Control     Gig 0/2           152              S I   WS-C2960- Fas 0/2
+\\
+\\
+Looking at the table above, we are looking at the perspective of Switch A. Switch A can see two switches (2 neighbours) that are connected to it.
+\\
+\\
+Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
+Switch           Gig 0/1           135              S I   WS-C2960- Fas 0/1
+\\
+\\
+Device ID is the name of the Switch.
+\\
+\\
+Local Intrfce is the interface of the switch we are running this command on (So the Switch called Switch is connected to our switch via local interface Gi01)
+\\
+\\
+Holdtme is the 180 second time, if this drips down to zero, that device will be removed from the CDP Neighbour table.
+\\
+\\
+Capability you can reference to this information at the top of the output:
+<file>
+Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
+                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
+                  D - Remote, C - CVTA, M - Two-port Mac Relay
+</file>
+So Capability S and I means the Switch can be a Switch and use IGMP.
+\\
+\\
+Platform - This is the detected Switch Model (WS-C2960-)
+\\
+\\
+Port ID is the interface of the Neighbour switch that is connected to this switch.
+\\
+\\
+==== CDP Neighbors Detail ====
+This command gives a more expansive set of information than "sh cdp neighbor"
+<file>
+sh cdp neighbor detail
+-------------------------
+Device ID: Switch
+Entry address(es):
+Platform: cisco WS-C2960-48TC-L,  Capabilities: Switch IGMP
+Interface: GigabitEthernet0/1,  Port ID (outgoing port): FastEthernet0/1
+Holdtime : 159 sec
+Version :
+Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(55)SE7, RELEASE SOFTWARE (fc1)
+Technical Support: http://www.cisco.com/techsupport
+Copyright (c) 1986-2013 by Cisco Systems, Inc.
+Compiled Mon 28-Jan-13 10:22 by prod_rel_team
+advertisement version: 2
+Protocol Hello:  OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF0000000000001CDEA7556980FF0000
+VTP Management Domain: ''
+Native VLAN: 10
+Duplex: full
+Management address(es):
+-------------------------
+Device ID: Rack4Control
+Entry address(es):
+  IP address: 192.168.200.128
+Platform: cisco WS-C2960-48TC-L,  Capabilities: Switch IGMP
+Interface: GigabitEthernet0/2,  Port ID (outgoing port): FastEthernet0/2
+Holdtime : 175 sec
+Version :
+Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(55)SE7, RELEASE SOFTWARE (fc1)
+Technical Support: http://www.cisco.com/techsupport
+Copyright (c) 1986-2013 by Cisco Systems, Inc.
+Compiled Mon 28-Jan-13 10:22 by prod_rel_team
+advertisement version: 2
+Protocol Hello:  OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF0000000000001CDEA7556B80FF0000
+VTP Management Domain: ''
+Native VLAN: 1 (Mismatch)
+Duplex: full
+Management address(es):
+  IP address: 192.168.200.128
+</file>
+\\
+It is easy to see that there is much more detail about our neighbors here.
+\\
+\\
+==== Show CDP Interface ====
+This gives some basic CDP information for every interface in your switch.
+<file>
+sh cdp interface
+FastEthernet0 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/1 is up, line protocol is up
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/2 is up, line protocol is up
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/3 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/4 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/5 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/6 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/7 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/8 is up, line protocol is up
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/9 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/10 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/11 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/12 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/13 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/14 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/15 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/16 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/17 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/18 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/19 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/20 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/21 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/22 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/23 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/24 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/25 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/26 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/27 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/28 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/29 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/30 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/31 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/32 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/33 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/34 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/35 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/36 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/37 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/38 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/39 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/40 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/41 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/42 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/43 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/44 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/45 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/46 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/47 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet0/48 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet1/1 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet1/2 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet1/3 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+GigabitEthernet1/4 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+TenGigabitEthernet1/1 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+TenGigabitEthernet1/2 is down, line protocol is down
+  Encapsulation ARPA
+  Sending CDP packets every 60 seconds
+  Holdtime is 180 seconds
+</file>
+\\
+\\