OCPBUGS-19822 Additional Network and Mettalb cannot use same network

Author: kquinn1204

modules/nw-metallb-bgp-limitations.adoc

@@ -18,6 +18,13 @@ However, you can anticipate that a change in the number of `speaker` pods affect
 To avoid or reduce the likelihood of a service interruption, you can specify a node selector when you add a BGP peer.
 By limiting the number of nodes that start BGP sessions, a fault on a node that does not have a BGP session has no affect on connections to the service.
 
+[id="additional_network_and_metallb_limitation_{context}"]
+== Additional Network and MetalLB cannot use same network
+
+There is a limitation when using the same VLAN for both MetalLB and an additional network interface on a source pod. In such cases, a connection failure occurs, when the MetalLB IP and the source pod share the same node.
+
+You can address this by ensuring the MetalLB IP is in another subnet so the traffic coming from a pod would take the default gateway, which is OVN-K and reach the destination via the OVN overlay. Alternatively use a MACVLAN interface instead of a VLAN interface.
+
 [id="nw-metallb-bgp-limitations-single-asn_{context}"]
 == Support for a single ASN and a single router ID only