Trunk port not working between C3850 and C3560X

[RookieNet55]

Hi everyone,

I have C3560X switch which is the current core, trying to add a new switch C3850-24XS via the trunk port. The link status is up, I can see the lights on both ports physically. But no communication between the switches via trunk port, no CDP neighbours either. There is VTP on both switches, C3560X is server and C3850 is configured as client, I have double checked the passwords and they are good.

Any help is appreciated on getting this trunk up and running. I can provide more config info as required.

Below are some configurations.

C3560X side

ip routing

interface Vlan100
description Management VLAN
ip address 172.18.100.1 255.255.255.0

interface GigabitEthernet0/24
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport trunk allowed vlan 100
switchport mode trunk

sh int gi0/24 status

Port Name Status Vlan Duplex Speed Type
Gi0/24 new san test connected trunk a-full a-1000 10/100/1000BaseTX

VTP Version                     : running VTP2
Configuration Revision          : 17
Maximum VLANs supported locally : 1005
Number of existing VLANs        : 15
VTP Operating Mode              : Server
VTP Domain Name                 : CDCCORPVTP1
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Enabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x89 0x03 0xC4 0x18 0xAD 0x3D 0xAD 0xB3
Configuration last modified by 0.0.0.0 at 3-1-93 00:20:35
Local updater ID is 172.18.2.1 on interface Vl2 (lowest numbered VLAN interface found)

C3850 side

ip routing

interface Vlan100
ip address 172.18.100.9 255.255.255.0
!
ip route 0.0.0.0 0.0.0.0 172.18.100.1

interface TenGigabitEthernet1/0/24
switchport trunk native vlan 100
switchport trunk allowed vlan 100
switchport mode trunk

sh int te1/0/24 status

Port Name Status Vlan Duplex Speed Type
Te1/0/24 connected trunk a-full a-1000 10/100/1000BaseTX SFP

sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 2
VTP Domain Name                 : CDCCORPVTP1
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 0056.2bd9.1e80
Configuration last modified by 172.18.100.9 at 12-21-23 21:55:55

Feature VLAN:
--------------
VTP Operating Mode                : Client
Maximum VLANs supported locally   : 1005
Number of existing VLANs          : 7
Configuration Revision            : 0
MD5 digest                        : 0xB3 0x4C 0x27 0x65 0xCD 0x6D 0x7D 0x1C
                                    0xAF 0x5B 0x02 0x3A 0x60 0x47 0xA0 0xAF

[RookieNet55]

even with this config shouldn't the cdp neighbours at least be showing up ?

[MHM Cisco World]

You disable cdp ?

If not Solve the native  and make stp have one root and check again.

MHM

[RookieNet55]

Unless we disable the cdp on port it is enabled by default right ?

[MHM Cisco World]

Yes is enable by defualt.

MHM

[RookieNet55]

It is enabled but for some reason, even CDP is not showing any neighbours.

Okay so what you are suggesting is that I simply remove the native vlan on this trunk and just have vlan 100 as allowed ?

[MHM Cisco World]

Friend there are five trunk four have native vlan 100 and one have 218?

Can you check why is this appear 

MHM

[RookieNet55]

This was set up before me, but it seems to be done on purpose as it is connected a vpn appliance and want to have all traffic coming from that port to be tagged with that vlan 218.

[MHM Cisco World]

OK let me review all info you provide again 
thanks 
MHM

[RookieNet55]

Thank you for checking this.

Here is another detail I checked. The SFP used on C3850-24XS is "SFP-GE-T". On checking the SFP compatibility with my model, It is compatible.

[MHM Cisco World]

VLAN0100
  Spanning tree enabled protocol ieee
  Root ID    Priority    32868
             Address     0056.2bd9.1e80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32868  (priority 32768 sys-id-ext 100)
             Address     0056.2bd9.1e80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

VLAN0100
  Spanning tree enabled protocol ieee
  Root ID    Priority    32868
             Address     0018.7392.c600
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32868  (priority 32768 sys-id-ext 100)
             Address     0018.7392.c600
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

sh int gi0/24 status

Port      Name               Status       Vlan       Duplex  Speed Type
Gi0/24    SAN switch test    connected    trunk      a-full a-1000 10/100/1000BaseTX

sh int te1/0/24 status

Port         Name               Status       Vlan       Duplex  Speed Type
Te1/0/24                        connected    trunk      a-full a-1000 10/100/1000BaseTX SFP

from above the interface show connect BUT
the STP see two Root 
the CDP not even show neighbor 
so there is issue in SFP the packet is not seen from each side
so let check STP is it send receive the BPDU or not check that by below command 

cat#show spanning-tree interface gi0/24 detail

Port 130 (GigabitEthernet3/2) of MST00 is backup blocking
   Port path cost 20000, Port priority 128, Port Identifier 128.130.
   Designated root has priority 0, address 0007.4f1c.e847
   Designated bridge has priority 32768, address 00d0.003f.8800
   Designated port id is 128.129, designated path cost 2000019
   Timers: message age 4, forward delay 0, hold 0
   Number of transitions to forwarding state: 0
   Link type is point-to-point by default, Internal
   Loop guard is enabled by default on the port
   BPDU: sent X, received X

for CDP check 
SW# show cdp traffic

MHMN

[RookieNet55]

Here is what I tried to test the most basic item. I defaulted the config on both these interfaces on respective switches and then checked the CDP neighbours that doesn't show up anything. 

CDP neighbours should still show up when there is physical connectivity between the links right ? 

I will be onsite today, so I can test more SFP's and kepp you posted. But sincere thanks again for taking time to look into my problem.

[MHM Cisco World]

No thanks friend 

You are so welcome 

MHM