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Collapsed Core/Distribution Q: L3 VLANs and L2 Port Channels

John-Eddie
Level 1
Level 1

Hi All,

 

Basic architecture of the above network is:

-Collapsed core/distro utilizing a stack of two 3650s

-Edge/workgroup switches are other brands

-Each workgroup switch represents a separate /27 ip subnet.

-Each workgroup switch supports LACP and will have two ports uplinking to the 3650s (one on each)

-The switches are already configured for LACP on the uplink ports

 

Here's my question:

 

It seems that the correct way to approach this is to leave the workgroup switches as L2 devices, and have the two ports in the port channel on the 3650 as L2 switch ports, but with a VSI assigned to a VLAN for each port channel (the default gateway the workstations get from DHCP).

 

Example:

 

(on 3650 stack)

 

interface Port-channel21
switchport trunk allowed vlan 21
switchport mode trunk

 

interface GigabitEthernet1/0/48
switchport trunk allowed vlan 21
switchport mode trunk
channel-group 21 mode active
spanning-tree portfast disable

 

interface GigabitEthernet2/0/48
switchport trunk allowed vlan 21
switchport mode trunk
channel-group 21 mode active
spanning-tree portfast disable

 

interface Vlan21
ip address 172.31.252.129 255.255.255.224

 

Does this seem sane/a good idea?  Additionally, why don't the ports in the port channel show up as members of VLAN 21 when I issue "show vlan" (it's empty)?

 

Thanks!

 

John-Eddie

1 Reply 1

balaji.bandi
Hall of Fame
Hall of Fame

How big is the setup is very important when you designing the Collapsed Core/Distribution

 

If the small setup you can with smaller switch, 3650 look at the End of Sale and End of Life

 

Collapsed Core/Distribution - always look for 5 years plan, so you do not going to touch on day to day basis and plan more resilience as services are running through your Core.

 

If you have DHCP Server centrally you can use DHCP help to get IP address in the VLAN Interface config.

 

You can L2 Port channels to Collapsed Core/Distribution from Access Switch (look at the 3rd party compatable guide)

 

BB

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