You can configure IPv6 address as an update-source.
Starting from XCO 3.4.0 and SLX 20.5.30 and later, tenant BGP peer-groups support both IPv4 and IPv6 addresses as an update-source. The feature is supported on the following platforms: Extreme 8520, SLX 9540 or 9640, SLX 9150 or 9250, SLX 9740, Extreme 8820, and Extreme 8720.

Note
XCO versions below 3.4.0 and SLX versions below 20.5.3 support update-source attribute for tenant BGP peer-groups, but only IPv4 address can be configured as update-source.
efa tenant service bgp peer-group create --tenant <tenant-name> --name <peer-group-name>
--pg-name device-ip:peer-group-name --pg-update-source-ip device-ip,peer-group-name:update-source-ip
efa tenant service bgp peer-group update --tenant <tenant-name> --name <peer-group-name> --operation peer-group-add
--pg-name device-ip:peer-group-name --pg-update-source-ip device-ip,peer-group-name:update-source-ip
efa tenant service bgp peer-group create --tenant "tenant1" --name "bgpPeerGroup2"
--pg-name 10.20.246.15:bgppg2 --pg-asn 10.20.246.15,bgppg2:100 --pg-update-source-ip 10.20.246.15,bgppg2:10::10
efa tenant service bgp peer-group update --tenant "tenant1" --name "bgpPeerGroup2" --operation peer-group-add
--pg-name 10.20.246.15:bgppg1 --pg-asn 10.20.246.15,bgppg1:200 --pg-update-source-ip 10.20.246.15,bgppg1:10::20
efa tenant service bgp peer-group show --tenant tenant1 –detail
==============================================================================
Name : bgpPeerGroup2
Tenant : tenant1
State : bgp-pg-created
Description :
Peer Group
----------
Device IP : 10.20.246.15
Peer Group : bgppg2
Remote ASN : 100
Next Hop Self : false
Update Source IP : 10::10
BFD Enabled : false
BFD Interval :
BFD Rx :
BFD Multiplier :
MD5 Password :
Remove Private AS : false
Activate : Activate (afi)
true (ipv4)
false (ipv6)
Prefix List In :
Prefix List Out :
Route Map In :
Route Map Out :
Send Community :
Add Path Capability :
Add Path Advertise :
Dev State : provisioned
App State : cfg-in-sync
Device IP : 10.20.246.15
Peer Group : bgppg1
Remote ASN : 200
Next Hop Self : false
Update Source IP : 10::20
BFD Enabled : false
BFD Interval :
BFD Rx :
BFD Multiplier :
MD5 Password :
Remove Private AS : false
Activate : Activate (afi)
true (ipv4)
false (ipv6)
Prefix List In :
Prefix List Out :
Route Map In :
Route Map Out :
Send Community :
Add Path Capability :
Add Path Advertise :
Dev State : provisioned
App State : cfg-in-sync
=================================================================================
Rack1-Device1# sh run router bgp router bgp local-as 4200000000 capability as4-enable fast-external-fallover neighbor bgppg2 peer-group neighbor bgppg2 remote-as 100 neighbor bgppg2 update-source 10::10 neighbor bgppg1 peer-group neighbor bgppg1 remote-as 200 neighbor bgppg1 update-source 10::20 neighbor 10.20.20.3 remote-as 4200000000 neighbor 10.20.20.3 next-hop-self address-family ipv4 unicast network 172.31.254.24/32 network 172.31.254.43/32 maximum-paths 8 graceful-restart ! address-family ipv6 unicast ! address-family l2vpn evpn graceful-restart ! !Rack1-Device1# |