i have the same problem on vlan 642

in both side there are on a port channel tagged

in switch1

show running-config interface port-channel 8

switchport mode general

switchport general allowed vlan add 642 tagged

show interfaces port-channel 8

Channel   Ports                         Ch-Type  Hash Type Min-links Local Prf

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

Po8       Active: Te1/0/8, Te2/0/8      Dynamic  7         1         Disabled

Hash Algorithm Type

1 - Source MAC, VLAN, EtherType, source module and port Id

2 - Destination MAC, VLAN, EtherType, source module and port Id

3 - Source IP and source TCP/UDP port

4 - Destination IP and destination TCP/UDP port

5 - Source/Destination MAC, VLAN, EtherType, source MODID/port

6 - Source/Destination IP and source/destination TCP/UDP port

7 - Enhanced hashing mode

the port is up and active

but not luck with the interface vlan 642

i have put on mode access both the switch

but i get no luck

in the first switch the interface vlan is up

on the other one the interface vlan is down.

then as the interface vlan is down there s no traffic between them

first question yes

same status as the vlan 643 i try with 644 645 and then i stop same problem

then i follow my test on vlan 642

on the switch where thevinterface vlan 642 is down

i add on another port channel  the 3 the vlan 642 tagged in general mode and

now  therefore the interface vlan 642 became up.

i had an interface vlan on this switch and i can ping the 172.24.48.2

if i remove the vlan from the portchannel the interface vlan become down again.

the portchannel i want to use for connected my other backbone switchis the port channel 8 connected to port

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

Po8       Active: Te1/0/8, Te2/0/8      Dynamic  7         1         Disabled

i have activated lldp

show lldp remote-device Tengigabitethernet 1/0/8

LLDP Remote Device Summary

Local

Interface RemID   Chassis ID          Port ID           System Name

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

Te1/0/8   13      D0:67:E5:95:0A:4F   Te2/0/42            sw-cns-coeur

I can see the other switch

then the link is good.

That seems really a big issue

Well i have found the problem but not solve it

the vlan 642 was attached to a port channel that was blocked by the spanning tree protocol that s why it was down

my problem is now why this portchannel are blocked as i double checkec there is no loop in my network.

Here is my config

the VLAN in red are "routing" vlan. There are only defined between the two devices they connected.

the vlans in VLANS "word" are different from the vlan 638-641.

Therefore there s no loop on my network

the only thing i m a bit scared of is this thing

cisco use rapid-pvst+ protocol

the two stack of dell use rstp protocol ie a non per vlan protocol.

Should i migrate my two stacks of dell to mst in order to have spanning tree per vlan?