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CDP is showing the wrong information.

amjadkhan1920
Level 1
Level 1

dear all,

 

i have one core switch 3800 and access 2960 there is no loops no stp no ether channel no hub not bridge  straight connectivity with each other (point to point ) but once i put the show cdp neighbor on core it show me one switch with tow ports while going to the access layer and show it show correct any idea please  

23 Replies 23

dear all,

 

hope you are doing well 

 

i did all the possibility but this is strange may be IOS have some issues? but once you check the access layer all the information is correct while core mismatch 

 

CORETWO#ping 10.67.0.12
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.67.0.12, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/10 ms
CORETWO#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.64.6.196 232 0012.daf6.b53f ARPA Vlan11
Internet 10.64.7.78 108 0012.daf6.b53f ARPA Vlan11
Internet 10.67.0.12 16 e8ba.7078.2ec1 ARPA Vlan11
Internet 10.67.0.254 - 706e.6d51.ecd4 ARPA Vlan11
CORETWO#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.64.6.196 234 0012.daf6.b53f ARPA Vlan11
Internet 10.64.7.78 110 0012.daf6.b53f ARPA Vlan11
Internet 10.67.0.12 19 e8ba.7078.2ec1 ARPA Vlan11
Internet 10.67.0.254 - 706e.6d51.ecd4 ARPA Vlan11
CORETWO#cle
CORETWO#clear arp
CORETWO#
CORETWO#ping 10.67.0.12
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.67.0.12, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/10 ms
CORETWO#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.64.6.196 0 0012.daf6.b53f ARPA Vlan11
Internet 10.64.7.78 0 0012.daf6.b53f ARPA Vlan11
Internet 10.67.0.12 0 e8ba.7078.2ec1 ARPA Vlan11
Internet 10.67.0.254 - 706e.6d51.ecd4 ARPA Vlan11
CORETWO#
 

dear deepak below is the stp result 

CORETWO#sh sp

VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 24577
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0002
Spanning tree enabled protocol rstp
Root ID Priority 24578
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0003
Spanning tree enabled protocol rstp
Root ID Priority 24579
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32771 (priority 32768 sys-id-ext 3)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0011
Spanning tree enabled protocol rstp
Root ID Priority 20491
Address 706e.6d51.ec80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 20491 (priority 20480 sys-id-ext 11)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Desg FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0051
Spanning tree enabled protocol rstp
Root ID Priority 32819
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32819 (priority 32768 sys-id-ext 51)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

dear deepak below is the stp result 

CORETWO#sh sp

VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 24577
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0002
Spanning tree enabled protocol rstp
Root ID Priority 24578
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0003
Spanning tree enabled protocol rstp
Root ID Priority 24579
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32771 (priority 32768 sys-id-ext 3)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0011
Spanning tree enabled protocol rstp
Root ID Priority 20491
Address 706e.6d51.ec80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 20491 (priority 20480 sys-id-ext 11)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Desg FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p Peer(STP)
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p Peer(STP)
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

VLAN0051
Spanning tree enabled protocol rstp
Root ID Priority 32819
Address 0012.daf6.b500
Cost 4
Port 1 (TenGigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32819 (priority 32768 sys-id-ext 51)
Address 706e.6d51.ec80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/0/1 Root FWD 4 128.1 P2p
Te1/0/2 Desg FWD 4 128.2 P2p
Te1/0/3 Desg FWD 4 128.3 P2p Peer(STP)
Te1/0/4 Desg FWD 4 128.4 P2p Peer(STP)
Te1/0/5 Desg FWD 4 128.5 P2p Peer(STP)
Te1/0/6 Desg FWD 4 128.6 P2p Peer(STP)
Te1/0/7 Desg FWD 4 128.7 P2p
Te1/0/8 Desg FWD 4 128.8 P2p Peer(STP)
Te1/0/9 Desg FWD 4 128.9 P2p
Te1/0/10 Desg FWD 4 128.10 P2p Peer(STP)
Te1/0/11 Desg FWD 4 128.11 P2p Peer(STP)

 

Hello
What is connected to this port?
IT_Cabinet_3_2 Ten 1/0/8 155 S I WS-C2960S Gig 1/0/27

IT_Cabinet2 Ten 1/0/8 147 S I WS-C2960G Gig 0/24
IT_CABINET3 Ten 1/0/8 150 S I WS-C2960G Gig 0/21


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Kind Regards
Paul

dear paul ,

 

physically my self i pull new fiber cable 3 times i cross check my self  this is very strange and first time i am facing such a issue may be IOS have some bugs ?

dear paul,

 

physically ten1/0/8 is connected to IT_CABINET3 below is the details of access layer

 

IT_CABINET3#sh cdp nei
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

Device ID Local Intrfce Holdtme Capability Platform Port ID
CORETWO Gig 0/21 130 S I WS-C3850- Ten 1/0/8
IT_CABINET3#

dear paul,

 

physically ten1/0/8 is connected to IT_CABINET3 below is the details of access layer

 

IT_CABINET3#sh cdp nei
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

Device ID Local Intrfce Holdtme Capability Platform Port ID
CORETWO Gig 0/21 130 S I WS-C3850- Ten 1/0/8
IT_CABINET3#

Strange indeed.  1/0/3 and 1/0/8 on the Core switch have the same MAC address coming in?

dear this is very strange and first time i am facing this issue i know only possible when hub or bridge is  live with in infrastructure but here nothing i 3 time cross check the physical connectivity my self there is no loops no stp nothing 

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