adding vlan to a port-channel

[smithy14975]

I added a vlan to a port-channel on port the DR and the Switch uplinks.

I updated the DR first C9600

vlan 1010
name RONT08_PCCS

interface Po25

switchport trunk allowed vlan add 1010

Then I did the access switch side C9300

configure terminal
vlan 1010
name RONT08_PCCS

int Po1
switchport trunk allowed vlan add 1010

This resulted in a 15 second downtime on the access layer switch

Why  did this happen

I

[MHM Cisco World]

That normal STP start send bpdu to new VLAN and start new root election and this put the interface in BLK after the STP process end the link is UP and forward 

MHM

[balaji.bandi]

what is that IP address ? adding VLAN port-channel that should get that many ping loss,

where is that VLAN Root bridge before adding, how your STP changes in the network (need to know your network topology)

how many VLAN you have ?

[smithy14975]

The IP address is the access layer switch.

[balaji.bandi]

where is the source you pining from ?

what VLAN the Access layer MGMT IP belong to.

add above question here again :

where is that VLAN Root bridge before adding, how your STP changes in the network (need to know your network topology)

how many VLAN you have ?

[smithy14975]

Pinging from a totally different VLAN not on this access switch.  I made the change remotely.

Vlan108 is the data vlan as well as the management vlan

VLAN0108
Spanning tree enabled protocol rstp
Root ID Priority 4204
Address 88fc.5d2f.c880
Cost 3001
Port 3049 (Port-channel1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 49260 (priority 49152 sys-id-ext 108)
Address 3c26.e449.3300
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec
UplinkFast enabled but inactive in rapid-pvst mode

Vlan 1010 was the new vlan I added

VLAN1010
Spanning tree enabled protocol rstp
Root ID Priority 5106
Address 88fc.5d2f.c880
Cost 3001
Port 3049 (Port-channel1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 50162 (priority 49152 sys-id-ext 1010)
Address 3c26.e449.3300
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec
UplinkFast enabled but inactive in rapid-pvst mode

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Po1 Root FWD 3001 128.3049 P2p

Vlan 408 is the VOICE vlan

VLAN0408
Spanning tree enabled protocol rstp
Root ID Priority 4504
Address 88fc.5d2f.c880
Cost 3001
Port 3049 (Port-channel1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 49560 (priority 49152 sys-id-ext 408)
Address 3c26.e449.3300
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec
UplinkFast enabled but inactive in rapid-pvst mode

[smithy14975]

The Switch is dual connected to 2 DR's but the 2 DR's are set up as one vitual box.

[balaji.bandi]

You need to put sometime and collect all the device logs and collate and co-related the issue with the timings.

This required lot information need to gather environment, what was the status before and after change done.

do you have pre config logs collected and STP view before made change.

show spanning-tree vlan X detail

check the topology change occured :

show spanning-tree detail | in ieee|from|occur|is exec  

inconsistency :

show spanning-tree inconsistentports

 check some STP troubleshoot :

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/28943-170.html

[smithy14975]

On the DR

VLAN0108
Spanning tree enabled protocol rstp
Root ID Priority 4204
Address 88fc.5d2f.c880
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 4204 (priority 4096 sys-id-ext 108)
Address 88fc.5d2f.c880
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Po24 Desg FWD 1 128.2304 P2p
Po25 Desg FWD 1 128.2305 P2p

VLAN0408
Spanning tree enabled protocol rstp
Root ID Priority 4504
Address 88fc.5d2f.c880
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 4504 (priority 4096 sys-id-ext 408)
Address 88fc.5d2f.c880
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Po24 Desg FWD 1 128.2304 P2p

VLAN1010
Spanning tree enabled protocol rstp
Root ID Priority 5106
Address 88fc.5d2f.c880
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 5106 (priority 4096 sys-id-ext 1010)
Address 88fc.5d2f.c880
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Po25 Desg FWD 1 128.2305 P2p

[MHM Cisco World]

I run lab add VLAN 20 and ping 100000 between two router in VLAN 10 and there is no drop

since you use RSTP then the STP election of new vlan is isolate from old vlan 

there is something else 
can you check 
show logging 
did you see why the port is down ?

[smithy14975]

There was not an entry on May 24th when this happened in the logs reflecting any uplink, physical or port-channel, going down.

I asked an operation guy to look further but I have not heard back.  

[smithy14975]

Found this on the Distribution side

Fri, 24 May 09:25	RONTGRADR01	192.168.250.196	notice local7 1155: May 24 09:25:20.298 CDT: %SYS-5-CONFIG_I: Configured from console by xxxxxx on vty0 (10.146.193.0)
Fri, 24 May 09:26	RONTGRADR01	192.168.250.196	notice local7 1156: May 24 09:26:39.871 CDT: %SYS-5-CONFIG_I: Configured from console by xxxxxxx on vty0 (10.146.193.0)
Fri, 24 May 09:28	RONTGRADR01	192.168.250.196	notice local7 1158: May 24 09:28:05.574 CDT: %SYS-5-CONFIG_I: Configured from console by xxxxxxx on vty0 (10.146.193.0)
Fri, 24 May 09:28	RONTGRADR01	192.168.250.196	notice local7 1159: May 24 09:28:05.586 CDT: %PIM-5-DRCHG: DR change from neighbor 0.0.0.0 to 10.99.30.65 on interface Vlan1010
Fri, 24 May 09:29	RONTGRADR01	192.168.250.196	notice local7 1160: May 24 09:29:30.961 CDT: %SYS-5-CONFIG_I: Configured from console by xxxxxxx on vty0 (10.146.193.0)
Fri, 24 May 09:30	RONTGRADR01	192.168.250.196	notice local7 1161: May 24 09:30:35.120 CDT: %SYS-5-CONFIG_I: Configured from console by xxxxxxx on vty0 (10.146.193.0)
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	critical local7 1162: May 24 09:33:12.544 CDT: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel25 on VLAN1010. Inconsistent peer vlan.
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	critical local7 1163: May 24 09:33:12.544 CDT: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel25 on VLAN0108. Inconsistent local vlan.
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	error local7 1164: May 24 09:33:14.545 CDT: %LINK-3-UPDOWN: Interface Vlan1010, changed state to down
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	critical local7 1166: May 24 09:33:27.544 CDT: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel25 on VLAN1010. Port consistency restored.
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	critical local7 1167: May 24 09:33:27.544 CDT: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel25 on VLAN0108. Port consistency restored.
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	error local7 1168: May 24 09:33:30.256 CDT: %LINK-3-UPDOWN: Interface Vlan1010, changed state to up
Fri, 24 May 09:33	RONTGRADR01	192.168.250.196	notice local7 1170: May 24 09:33:31.985 CDT: %PIM-5-DRCHG: DR change from neighbor 0.0.0.0 to 10.99.30.65 on interface Vlan1010

[MHM Cisco World]

SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel25 on VLAN1010. Inconsistent peer vlan.

critical local7 1163: May 24 09:33:12.544 CDT: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel25 on VLAN0108. Inconsistent local vlan.

It sure then STP' 

Are vlan108 is native vlan ? 

MHM