I would have an outage window just in case. Since you already have 2 diffrent port channels configure on you VSS boxes, all you have to do is add a second 10Gig link to the same port channels.
At the end, you config for you VSL links should look like this:
I'm trying to do this exact procedure today, staging the kit for a customer.
We have had a single VSL etherchannel link to start with because only 1 10GB module was ordered with each chassis.
I've now come to add the second link into the etherchannel and the vsl will not come up over both links.
The second link simply doesn't come up when connected after the etherchannel config is applied, however if I pull the working VSL link, the second link comes on immediately but the active chassis goes into recovery mode and reboots. It then comes back up disabled, while the second chassis is active,
I can still bring the VSS up with one link but not with two connected.
If I restart both switches at the same time they do come up with one VSL link while the second stays down. My feeling is that maybe this is happening because the VSL etherchannel was not configured for two links before the switch was converted to virtual mode, however this is just guess work because I can see that the config looks ok..
interface Port-channel1
no switchport
no ip address
switch virtual link 1
mls qos trust cos
no mls qos channel-consistency
end
emea-oxf-vss#
emea-oxf-vss# sh run int po2
Building configuration...
Current configuration : 135 bytes
!
interface Port-channel2
no switchport
no ip address
switch virtual link 2
mls qos trust cos
no mls qos channel-consistency
end
emea-oxf-vss#
emea-oxf-vss#
emea-oxf-vss# sh run int t1/7/4
Building configuration...
Current configuration : 115 bytes
!
interface TenGigabitEthernet1/7/4
no switchport
no ip address
mls qos trust cos
channel-group 1 mode on
end
emea-oxf-vss# sh run int t1/7/5
Building configuration...
Current configuration : 115 bytes
!
interface TenGigabitEthernet1/7/5
no switchport
no ip address
mls qos trust cos
channel-group 1 mode on
end
emea-oxf-vss# sh run int t2/7/4
Building configuration...
Current configuration : 115 bytes
!
interface TenGigabitEthernet2/7/4
no switchport
no ip address
mls qos trust cos
channel-group 2 mode on
end
emea-oxf-vss# sh run int t2/7/5
Building configuration...
Current configuration : 115 bytes
!
interface TenGigabitEthernet2/7/5
no switchport
no ip address
mls qos trust cos
channel-group 2 mode on
end
emea-oxf-vss#sh switch virtual redundancy
My Switch Id = 1
Peer Switch Id = 2
Last switchover reason = none
Configured Redundancy Mode = sso
Operating Redundancy Mode = sso
Switch 1 Slot 7 Processor Information :
-----------------------------------------------
Current Software state = ACTIVE
Uptime in current state = 5 minutes
Image Version = Cisco IOS Software, s72033_rp Software (s72033_rp-ADVENTERPRISEK9_WAN-M), Version 12.2(33)SXI6, RELEASE SOFTWARE (fc4)
This should be simple as adding additional member-link to an existing EtherChannel. VSL leverages many of the existing EtherChannel design. Assuming there is no hardware issues (bad fiber/connectors etc) adding/links will not require any additional downtime and can be done in production network:
BEWARE VSS OPERATION WILL BE IMPACTED IF LAST MEMBER-LINKS FROM VSL ETHERCHANNEL IS REMOVED OR SHUTDOWN.
Refer to following logs as:
Setup
--------
Quad-Sup design with 4 VSL ports from SW1 and SW2 chassis
As you can see above the sh switch virtual link shows only one link. When I disconnect Te1/4/1 then Te1/6/4 kicks in.
test# *Aug 12 12:35:10.287: %VSLP-SW1_SP-3-VSLP_LMP_FAIL_REASON: Te1/4/1: Link down *Aug 12 12:35:10.287: %VSL-SW1_SP-5-VSL_CNTRL_LINK: New VSL Control Link Te1/6/4 *Aug 12 12:35:10.287: %VSLP-SW2_SPSTBY-3-VSLP_LMP_FAIL_REASON: Te2/4/1: Link down *Aug 12 12:35:10.287: %VSL-SW2_SPSTBY-5-VSL_CNTRL_LINK: New VSL Control Link Te2/6/4 test#
I m guessing when you say single link in VSL, you are comparing between number interfaces bundled in VSL EtherChannel (shown in "show interface vsl") versus VSL Control Link (shown in "show switch virtual link").
If I understood correctly, then there are no issues to VSL. The VSL is Layer 1 logical system interface. Out of multiple VSL bundled interfaces, during bootup process both chassis in virtual-switch mode negotiates and identifies just single interface to run all system control traffic.
System control traffic is all internal control and management communication to virtually manage the module/ports between two chassis. So even though when you have bundle multiple physical interfaces in VSL EtherChannel there will always single control-link needed. Rest are available for redundancy and handle data backplane if and when needed...
