Enabling Redundancy on 9800 WLC With VSS switch

[ahmad.syed]

Hi Team,

I am deploying 9800 WLC , which is going to use  Single VSS switch (or stack/VSL pair/modular switch) with RP back-to-back as per below connectivity. Need support for config related to LAG on WLC and switch . Please help

[Haydn Andrews · Accepted solution]

Ports from each WLC go to a port channel on the VSS Switch

Port Channel Numbers do not have to match on VSS and WLC - although some people prefer that but may not be possible dependant on port channel IDs already in use on VSS switch.

WLC

WLC(Config)#interface range XX - XX Interfaces on WLC to be part of Port Channel

WLC(Config-if)#switchport mode trunk

WLC(Config-if)#switchport trunk allow vlan <XX> If restricting VLANs

WLC(Config-if)#Any other port config you require

WLC(Config-if)#channel-group <X> mode on Port Channel value - can be same on both WLCs as locally significant

WLC(Config)#interface PortChannel X

WLC(Config-if)#switchport mode trunk

WLC(Config-if)#switchport trunk allow vlan <XX> If restricting VLANs

WLC(Config-if)#Any other port config you require

Switch

Repeat twice with seperate Port Channel IDs

Switch(Config)#interface range XX - XX Interfaces on Switch to be part of Port Channel (Ensure that one is on each switch)

Switch(Config-if)#switchport mode trunk

Switch(Config-if)#switchport trunk allow vlan <XX> If restricting VLANs

Switch(Config-if)#Any other port config you require

Switch(Config-if)#channel-group <X> mode on Port Channel value - can be same on both WLCs as locally significant

Switch(Config)#interface PortChannel X

Switch(Config-if)#switchport mode trunk

Switch(Config-if)#switchport trunk allow vlan <XX> If restricting VLANs

Verification same on both WLC and Switch

#Show etherchannel summary

Switch(Config-if)#Any other port config you require

Once completed ensure you can access both WLCs then follow the 9800 SSO deployment guide

https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-3/deployment-guide/c9800-ha-sso-deployment-guide-rel-17-3.pdf 

[ahmad.syed]

Hi @Haydn Andrews ,

Thanks for your response.  

One query, when we are doing configuration on switch end , as suggested having same port channel as WLC is not mandatory , then can we go with different port channel ID at all 4 location meaning on both WLC and both switch 

[Haydn Andrews]

The port channel ID can be different on all 4 locations if you want. The only ones that have to actually be different are the two on the switch side, otherwise technically you could have 3 x Port Channel ID 1 if you really wanted to, or 4 different ones

[Arshad Safrulla]

To add on top of this excellent reply.

1. You can use LACP for LAG's as this is supported from 17.1.X codes when WLC's are in HA.

2. You can add spanning-tree portfast trunk on the uplinks.

3. Distribute the WLC downlink ports across different modules if switch is modular or ASICs if switch is fixed chassis.

4. Use RMI+RP with Gateway reachability check enabled.

5. Configure the service ports of each box and connect it to management switch (if there)