Trunk not getting up

[JAISONTHOMAS]

Hi,

We have an office with two cabinets. One is where our primary switch is located in the basement cabinet and there is a small cabinet on the first floor. Uplink for the first-floor switch is from the basement cabinet switch, and both are Catalyst 9200 stacks. We have power issues in the first-floor cabinet that is being investigated by the electrician now.

After every power issue, the first floor stack gets rebooted, but after reboot, the uplink between the switches doesn't come up. So we have to log in to the basement switch and bounce the uplink interface manually.

Below are the switch uplink configs,

SW_01#sh run int Gig 3/1/1
Building configuration...

Current configuration : 170 bytes
!
interface GigabitEthernet3/1/1
description UPLINK-SW__02
switchport trunk allowed vlan 100-102,200,300
switchport mode trunk
ip dhcp snooping trust
end

---------------------

SW__02#sh run int Gig 1/1/1
Building configuration...

Current configuration : 132 bytes
!
interface GigabitEthernet1/1/1
switchport trunk allowed vlan 100-102,200,300
switchport mode trunk
ip dhcp snooping trust
end

Any idea why the uplink is not coming up after the switch reboot?

Thank you

[pieterh]

no idea you there is not enough information in your post.
try to collect the console-logs and port-status of those switches at the time of a power-outage, there may be some information there,
(interface may be err-disabled for some reason?)

one remark the command "ip dhcp snooping trust" only has use on the uplink pointing to your DHCP server!

if you DO have a bidirectional path over this trunk to your DHCP server, than there may be an unintended loop in your network?
if this is an intended loop (intended as backup link) , then this loop may block your trunk port for comming up after power outage.

[Jens Albrecht]

Hello @JAISONTHOMAS,

you need to check the logs on both sides to see the reason for this problem as @pieterh already mentioned.

However, if I understand your post correctly, then you have setup 2 individual trunk links between 2 stacks, right?

In this case it is strongly recommended to configure these links as an etherchannel and this config change might already solve your problem!

With your current setup STP will always block one of the links and STP is a well-known reason for lots of trouble.
Bundling these 2 links together will not only avoid STP issues but also double the available bandwidth between your stacks.

HTH!

[JAISONTHOMAS]

Hello folks, sorry if my post was incomplete.

Just to clarify, we don't have dual uplinks between these switches. Just one fibre link connecting these switches

Unfortunately I don't have the logs of the second switch during its reboot.

Ideally after the restart, uplink should come up, but that's not happening here.

[pieterh]

>>> Unfortunately I don't have the logs of the second switch during its reboot <<<
does this mean you DO have logs from the first switch ?
can you post some relevant part here?

did you configure one of the switches as spanning-tree root (using spanning-tree priority)?
this can help your network to a more stable configuration.
can you post output from "show spanning-tree" on both switches?

[rsthakur · Accepted solution]

"I'm a bit late to join the Party,

but it looks like this is a classic Native VLAN mismatch issue. You should check your main switch — you’ll likely find logs similar to this:"

This usually means the two ends of a trunk link have different native VLANs configured. It can lead to untagged traffic being misrouted or dropped. Make sure both sides of the trunk have the same native VLAN setting:

interface GigabitEthernet0/1
switchport trunk native vlan XX

switchport mode trunk

[JAISONTHOMAS]

thanks mate, that was the issue native vlan was missing in the config which I didn't really check.

Many thanks everyone, for your inputs.

[JAISONTHOMAS]

Just checked the logs and the SW1 doesn't have any logs of yesterday. So I lost them as well

Spanning Tree - SW1

SW__01#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 32868
Address 7488.bbba.0b80
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 7488.bbba.0b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/1/1 Desg FWD 20000 128.49 P2p
Gi2/0/1 Desg FWD 20000 128.97 P2p Edge
Gi3/0/1 Desg FWD 20000 128.193 P2p
Gi3/0/6 Desg FWD 200000 128.198 P2p Edge
Gi3/0/8 Desg FWD 20000 128.200 P2p
Gi3/0/9 Desg FWD 200000 128.201 P2p Edge
Gi3/0/11 Desg FWD 200000 128.203 P2p Edge
Gi3/0/13 Desg FWD 200000 128.205 P2p Edge
Gi3/0/20 Desg FWD 20000 128.212 P2p
Gi3/0/23 Desg FWD 200000 128.215 P2p Edge
Gi3/0/25 Desg FWD 200000 128.217 P2p Edge
Gi3/0/45 Desg FWD 20000 128.237 P2p Edge
Gi3/0/46 Desg FWD 200000 128.238 P2p Edge
Gi3/0/47 Desg FWD 200000 128.239 P2p Edge
Gi3/0/48 Desg FWD 200000 128.240 P2p Edge
Gi3/1/1 Desg FWD 20000 128.241 P2p

VLAN0101
Spanning tree enabled protocol rstp
Root ID Priority 32869
Address 7488.bbba.0b80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32869 (priority 32768 sys-id-ext 101)
Address 7488.bbba.0b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/1 Desg FWD 20000 128.49 P2p
Gi3/0/4 Desg FWD 20000 128.196 P2p
Gi3/0/8 Desg FWD 20000 128.200 P2p
Gi3/0/20 Desg FWD 20000 128.212 P2p
Gi3/1/1 Desg FWD 20000 128.241 P2p

VLAN0102
Spanning tree enabled protocol rstp
Root ID Priority 32870
Address 7488.bbba.0b80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32870 (priority 32768 sys-id-ext 102)
Address 7488.bbba.0b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/6 Desg FWD 20000 128.6 P2p Edge
Gi1/0/7 Desg FWD 20000 128.7 P2p Edge
Gi1/0/10 Desg FWD 20000 128.10 P2p Edge
Gi1/0/13 Desg FWD 20000 128.13 P2p Edge
Gi1/0/36 Desg FWD 20000 128.36 P2p Edge
Gi1/0/38 Desg FWD 20000 128.38 P2p Edge
Gi1/0/41 Desg FWD 20000 128.41 P2p Edge
Gi1/0/42 Desg FWD 20000 128.42 P2p Edge
Gi1/1/1 Desg FWD 20000 128.49 P2p
Gi2/0/3 Desg FWD 20000 128.99 P2p Edge
Gi2/0/5 Desg FWD 20000 128.101 P2p Edge
Gi2/0/8 Desg FWD 20000 128.104 P2p Edge
Gi2/0/10 Desg FWD 20000 128.106 P2p Edge
Gi2/0/12 Desg FWD 20000 128.108 P2p Edge
Gi2/0/15 Desg FWD 20000 128.111 P2p Edge
Gi2/0/17 Desg FWD 20000 128.113 P2p Edge
Gi2/0/18 Desg FWD 20000 128.114 P2p Edge
Gi2/0/19 Desg FWD 20000 128.115 P2p Edge
Gi2/0/20 Desg FWD 200000 128.116 P2p Edge
Gi3/0/5 Desg FWD 20000 128.197 P2p
Gi3/0/8 Desg FWD 20000 128.200 P2p
Gi3/0/12 Desg FWD 20000 128.204 P2p Edge
Gi3/0/14 Desg FWD 20000 128.206 P2p Edge
Gi3/0/16 Desg FWD 20000 128.208 P2p Edge
Gi3/0/20 Desg FWD 20000 128.212 P2p
Gi3/1/1 Desg FWD 20000 128.241 P2p

VLAN0200
Spanning tree enabled protocol rstp
Root ID Priority 32968
Address 7488.bbba.0b80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32968 (priority 32768 sys-id-ext 200)
Address 7488.bbba.0b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/6 Desg FWD 20000 128.6 P2p Edge
Gi1/0/7 Desg FWD 20000 128.7 P2p Edge
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/0/10 Desg FWD 20000 128.10 P2p Edge
Gi1/0/13 Desg FWD 20000 128.13 P2p Edge
Gi1/0/36 Desg FWD 20000 128.36 P2p Edge
Gi1/0/38 Desg FWD 20000 128.38 P2p Edge
Gi1/0/41 Desg FWD 20000 128.41 P2p Edge
Gi1/0/42 Desg FWD 20000 128.42 P2p Edge
Gi1/1/1 Desg FWD 20000 128.49 P2p
Gi2/0/1 Desg FWD 20000 128.97 P2p Edge
Gi2/0/3 Desg FWD 20000 128.99 P2p Edge
Gi2/0/5 Desg FWD 20000 128.101 P2p Edge
Gi2/0/8 Desg FWD 20000 128.104 P2p Edge
Gi2/0/10 Desg FWD 20000 128.106 P2p Edge
Gi2/0/12 Desg FWD 20000 128.108 P2p Edge
Gi2/0/15 Desg FWD 20000 128.111 P2p Edge
Gi2/0/17 Desg FWD 20000 128.113 P2p Edge
Gi2/0/18 Desg FWD 20000 128.114 P2p Edge
Gi2/0/19 Desg FWD 20000 128.115 P2p Edge
Gi2/0/20 Desg FWD 200000 128.116 P2p Edge
Gi3/0/2 Desg FWD 20000 128.194 P2p
Gi3/0/6 Desg FWD 200000 128.198 P2p Edge
Gi3/0/9 Desg FWD 200000 128.201 P2p Edge
Gi3/0/11 Desg FWD 200000 128.203 P2p Edge
Gi3/0/12 Desg FWD 20000 128.204 P2p Edge
Gi3/0/13 Desg FWD 200000 128.205 P2p Edge
Gi3/0/14 Desg FWD 20000 128.206 P2p Edge
Gi3/0/16 Desg FWD 20000 128.208 P2p Edge
Gi3/0/23 Desg FWD 200000 128.215 P2p Edge
Gi3/0/25 Desg FWD 200000 128.217 P2p Edge
Gi3/0/45 Desg FWD 20000 128.237 P2p Edge
Gi3/0/46 Desg FWD 200000 128.238 P2p Edge
Gi3/0/47 Desg FWD 200000 128.239 P2p Edge
Gi3/0/48 Desg FWD 200000 128.240 P2p Edge
Gi3/1/1 Desg FWD 20000 128.241 P2p

VLAN0300
Spanning tree enabled protocol rstp
Root ID Priority 33068
Address 7488.bbba.0b80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33068 (priority 32768 sys-id-ext 300)
Address 7488.bbba.0b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/1 Desg FWD 20000 128.49 P2p
Gi3/0/3 Desg FWD 20000 128.195 P2p
Gi3/0/8 Desg FWD 20000 128.200 P2p
Gi3/0/20 Desg FWD 20000 128.212 P2p
Gi3/1/1 Desg FWD 20000 128.241 P2p

SW__01#

Spanning Tree SW 2

SW__02#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 32868
Address 7488.bbba.0b80
Cost 20000
Port 25 (GigabitEthernet1/1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address d0e0.425e.5980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/2 Desg FWD 20000 128.2 P2p Edge
Gi1/0/3 Desg FWD 20000 128.3 P2p
Gi1/0/4 Desg FWD 20000 128.4 P2p Edge
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/0/19 Desg FWD 20000 128.19 P2p
Gi1/0/20 Desg FWD 20000 128.20 P2p
Gi1/1/1 Root FWD 20000 128.25 P2p
Gi2/0/2 Desg FWD 200000 128.98 P2p Edge
Gi2/0/5 Desg FWD 200000 128.101 P2p Edge
Gi2/0/6 Desg FWD 200000 128.102 P2p Edge
Gi2/0/9 Desg FWD 200000 128.105 P2p Edge
Gi2/0/11 Desg FWD 200000 128.107 P2p Edge
Gi2/0/12 Desg FWD 200000 128.108 P2p Edge
Gi2/0/13 Desg FWD 200000 128.109 P2p Edge
Gi2/0/14 Desg FWD 200000 128.110 P2p Edge
Gi2/0/16 Desg FWD 200000 128.112 P2p Edge
Gi2/0/24 Desg FWD 200000 128.120 P2p Edge
Gi2/0/25 Desg FWD 200000 128.121 P2p Edge
Gi2/0/26 Desg FWD 200000 128.122 P2p Edge
Gi2/0/28 Desg FWD 200000 128.124 P2p Edge
Gi2/0/29 Desg FWD 200000 128.125 P2p Edge
Gi2/0/31 Desg FWD 200000 128.127 P2p Edge
Gi2/0/32 Desg FWD 200000 128.128 P2p Edge
Gi2/0/36 Desg FWD 200000 128.132 P2p Edge
Gi2/0/38 Desg FWD 200000 128.134 P2p Edge
Gi2/0/39 Desg FWD 200000 128.135 P2p Edge
Gi2/0/42 Desg FWD 200000 128.138 P2p Edge
Gi2/0/43 Desg FWD 200000 128.139 P2p Edge
Gi2/0/44 Desg FWD 200000 128.140 P2p Edge
Gi2/0/45 Desg FWD 200000 128.141 P2p Edge
Gi2/0/46 Desg FWD 200000 128.142 P2p Edge
Gi3/0/14 Desg FWD 200000 128.206 P2p Edge
Gi3/0/30 Desg FWD 200000 128.222 P2p Edge
Gi3/0/39 Desg FWD 20000 128.231 P2p Edge

VLAN0101
Spanning tree enabled protocol rstp
Root ID Priority 32869
Address 7488.bbba.0b80
Cost 20000
Port 25 (GigabitEthernet1/1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Bridge ID Priority 32869 (priority 32768 sys-id-ext 101)
Address d0e0.425e.5980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/3 Desg FWD 20000 128.3 P2p
Gi1/0/10 Desg FWD 200000 128.10 P2p Edge
Gi1/0/12 Desg FWD 200000 128.12 P2p Edge
Gi1/0/19 Desg FWD 20000 128.19 P2p
Gi1/0/20 Desg FWD 20000 128.20 P2p
Gi1/1/1 Root FWD 20000 128.25 P2p
Gi2/0/30 Desg FWD 20000 128.126 P2p Edge
Gi3/0/2 Desg FWD 20000 128.194 P2p Edge
Gi3/0/3 Desg FWD 20000 128.195 P2p Edge
Gi3/0/4 Desg FWD 20000 128.196 P2p Edge
Gi3/0/7 Desg FWD 20000 128.199 P2p Edge
Gi3/0/10 Desg FWD 20000 128.202 P2p Edge
Gi3/0/11 Desg FWD 20000 128.203 P2p Edge
Gi3/0/15 Desg FWD 20000 128.207 P2p Edge
Gi3/0/19 Desg FWD 20000 128.211 P2p Edge
Gi3/0/21 Desg FWD 20000 128.213 P2p Edge
Gi3/0/24 Desg FWD 20000 128.216 P2p Edge
Gi3/0/31 Desg FWD 20000 128.223 P2p Edge
Gi3/0/33 Desg FWD 20000 128.225 P2p Edge
Gi3/0/35 Desg FWD 20000 128.227 P2p Edge
Gi3/0/41 Desg FWD 20000 128.233 P2p Edge
Gi3/0/42 Desg FWD 200000 128.234 P2p Edge
Gi3/0/45 Desg FWD 20000 128.237 P2p Edge

VLAN0200
Spanning tree enabled protocol rstp
Root ID Priority 32968
Address 7488.bbba.0b80
Cost 20000
Port 25 (GigabitEthernet1/1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32968 (priority 32768 sys-id-ext 200)
Address d0e0.425e.5980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/2 Desg FWD 20000 128.2 P2p Edge
Gi1/0/4 Desg FWD 20000 128.4 P2p Edge
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/0/10 Desg FWD 200000 128.10 P2p Edge
Gi1/0/12 Desg FWD 200000 128.12 P2p Edge
Gi1/1/1 Root FWD 20000 128.25 P2p
Gi2/0/2 Desg FWD 200000 128.98 P2p Edge
Gi2/0/5 Desg FWD 200000 128.101 P2p Edge
Gi2/0/6 Desg FWD 200000 128.102 P2p Edge
Gi2/0/9 Desg FWD 200000 128.105 P2p Edge
Gi2/0/11 Desg FWD 200000 128.107 P2p Edge

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi2/0/12 Desg FWD 200000 128.108 P2p Edge
Gi2/0/13 Desg FWD 200000 128.109 P2p Edge
Gi2/0/14 Desg FWD 200000 128.110 P2p Edge
Gi2/0/16 Desg FWD 200000 128.112 P2p Edge
Gi2/0/24 Desg FWD 200000 128.120 P2p Edge
Gi2/0/25 Desg FWD 200000 128.121 P2p Edge
Gi2/0/26 Desg FWD 200000 128.122 P2p Edge
Gi2/0/28 Desg FWD 200000 128.124 P2p Edge
Gi2/0/29 Desg FWD 200000 128.125 P2p Edge
Gi2/0/30 Desg FWD 20000 128.126 P2p Edge
Gi2/0/31 Desg FWD 200000 128.127 P2p Edge
Gi2/0/32 Desg FWD 200000 128.128 P2p Edge
Gi2/0/36 Desg FWD 200000 128.132 P2p Edge
Gi2/0/38 Desg FWD 200000 128.134 P2p Edge
Gi2/0/39 Desg FWD 200000 128.135 P2p Edge
Gi2/0/42 Desg FWD 200000 128.138 P2p Edge
Gi2/0/43 Desg FWD 200000 128.139 P2p Edge
Gi2/0/44 Desg FWD 200000 128.140 P2p Edge
Gi2/0/45 Desg FWD 200000 128.141 P2p Edge
Gi2/0/46 Desg FWD 200000 128.142 P2p Edge
Gi3/0/2 Desg FWD 20000 128.194 P2p Edge
Gi3/0/3 Desg FWD 20000 128.195 P2p Edge
Gi3/0/4 Desg FWD 20000 128.196 P2p Edge
Gi3/0/7 Desg FWD 20000 128.199 P2p Edge
Gi3/0/10 Desg FWD 20000 128.202 P2p Edge
Gi3/0/11 Desg FWD 20000 128.203 P2p Edge
Gi3/0/14 Desg FWD 200000 128.206 P2p Edge
Gi3/0/15 Desg FWD 20000 128.207 P2p Edge
Gi3/0/19 Desg FWD 20000 128.211 P2p Edge
Gi3/0/21 Desg FWD 20000 128.213 P2p Edge
Gi3/0/24 Desg FWD 20000 128.216 P2p Edge
Gi3/0/30 Desg FWD 200000 128.222 P2p Edge
Gi3/0/31 Desg FWD 20000 128.223 P2p Edge
Gi3/0/33 Desg FWD 20000 128.225 P2p Edge
Gi3/0/35 Desg FWD 20000 128.227 P2p Edge
Gi3/0/39 Desg FWD 20000 128.231 P2p Edge
Gi3/0/41 Desg FWD 20000 128.233 P2p Edge
Gi3/0/42 Desg FWD 200000 128.234 P2p Edge
Gi3/0/45 Desg FWD 20000 128.237 P2p Edge

VLAN0300
Spanning tree enabled protocol rstp
Root ID Priority 33068
Address 7488.bbba.0b80
Cost 20000
Port 25 (GigabitEthernet1/1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33068 (priority 32768 sys-id-ext 300)
Address d0e0.425e.5980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/3 Desg FWD 20000 128.3 P2p
Gi1/0/19 Desg FWD 20000 128.19 P2p
Gi1/0/20 Desg FWD 20000 128.20 P2p
Gi1/1/1 Root FWD 20000 128.25 P2p

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

SW__02#