diff --git a/pkg/agent/agent.go b/pkg/agent/agent.go
index 57db78cae5c..8c2f7ea33e9 100644
--- a/pkg/agent/agent.go
+++ b/pkg/agent/agent.go
@@ -773,7 +773,12 @@ func (i *Initializer) configureGatewayInterface(gatewayIface *interfacestore.Int
 			klog.ErrorS(err, "Failed to persist interface MAC address", "interface", gatewayIface.InterfaceName, "mac", gwMAC)
 		}
 	}
-	i.nodeConfig.GatewayConfig = &config.GatewayConfig{Name: i.hostGateway, MAC: gwMAC, OFPort: uint32(gatewayIface.OFPort)}
+	i.nodeConfig.GatewayConfig = &config.GatewayConfig{
+		Name:      i.hostGateway,
+		MAC:       gwMAC,
+		LinkIndex: gwLinkIdx,
+		OFPort:    uint32(gatewayIface.OFPort),
+	}
 	gatewayIface.IPs = []net.IP{}
 	if i.networkConfig.TrafficEncapMode.IsNetworkPolicyOnly() {
 		// Assign IP to gw as required by SpoofGuard.
@@ -789,7 +794,6 @@ func (i *Initializer) configureGatewayInterface(gatewayIface *interfacestore.Int
 		return nil
 	}
 
-	i.nodeConfig.GatewayConfig.LinkIndex = gwLinkIdx
 	// Allocate the gateway IP address for each Pod CIDR allocated to the Node. For each CIDR,
 	// the first address in the subnet is assigned to the host gateway interface.
 	podCIDRs := []*net.IPNet{i.nodeConfig.PodIPv4CIDR, i.nodeConfig.PodIPv6CIDR}
diff --git a/pkg/agent/route/route_linux.go b/pkg/agent/route/route_linux.go
index 31890415aa5..5bb17854863 100644
--- a/pkg/agent/route/route_linux.go
+++ b/pkg/agent/route/route_linux.go
@@ -361,30 +361,31 @@ func (c *Client) syncRoute() error {
 	return nil
 }
 
-// syncIPSet ensures that the required ipset exists and it has the initial members.
+// syncIPSet ensures that the required ipset exists, and it has the initial members.
 func (c *Client) syncIPSet() error {
-	// In policy-only mode, Node Pod CIDR is undefined.
-	if c.networkConfig.TrafficEncapMode.IsNetworkPolicyOnly() {
-		return nil
-	}
-	if err := c.ipset.CreateIPSet(antreaPodIPSet, ipset.HashNet, false); err != nil {
-		return err
-	}
-	if err := c.ipset.CreateIPSet(antreaPodIP6Set, ipset.HashNet, true); err != nil {
-		return err
-	}
-
-	// Loop all valid PodCIDR and add into the corresponding ipset.
-	for _, podCIDR := range []*net.IPNet{c.nodeConfig.PodIPv4CIDR, c.nodeConfig.PodIPv6CIDR} {
-		if podCIDR != nil {
-			ipsetName := getIPSetName(podCIDR.IP)
-			if err := c.ipset.AddEntry(ipsetName, podCIDR.String()); err != nil {
-				return err
+	// Create the ipsets to store all Pod CIDRs for constructing full-mesh routing in encap/noEncap/hybrid modes. In
+	// networkPolicyOnly mode, Antrea is not responsible for IPAM, so CIDRs are not available and the ipsets should not
+	// be created.
+	if !c.networkConfig.TrafficEncapMode.IsNetworkPolicyOnly() {
+		if err := c.ipset.CreateIPSet(antreaPodIPSet, ipset.HashNet, false); err != nil {
+			return err
+		}
+		if err := c.ipset.CreateIPSet(antreaPodIP6Set, ipset.HashNet, true); err != nil {
+			return err
+		}
+		// Loop all valid Pod CIDRs and add them into the corresponding ipset.
+		for _, podCIDR := range []*net.IPNet{c.nodeConfig.PodIPv4CIDR, c.nodeConfig.PodIPv6CIDR} {
+			if podCIDR != nil {
+				ipsetName := getIPSetName(podCIDR.IP)
+				if err := c.ipset.AddEntry(ipsetName, podCIDR.String()); err != nil {
+					return err
+				}
 			}
 		}
 	}
 
-	// If proxy full is enabled, create NodePort ipset.
+	// ProxyAll is available in all traffic modes. If proxyAll is enabled, create the ipsets to store the pairs of Node
+	// IP and NodePort.
 	if c.proxyAll {
 		if err := c.ipset.CreateIPSet(antreaNodePortIPSet, ipset.HashIPPort, false); err != nil {
 			return err
@@ -409,6 +410,8 @@ func (c *Client) syncIPSet() error {
 		})
 	}
 
+	// FlexibleIPAM is available in noEncap mode. There is a validation in Antrea configuration about this traffic mode
+	// when FlexibleIPAM is enabled.
 	if c.connectUplinkToBridge {
 		if err := c.ipset.CreateIPSet(localAntreaFlexibleIPAMPodIPSet, ipset.HashIP, false); err != nil {
 			return err
@@ -418,6 +421,7 @@ func (c *Client) syncIPSet() error {
 		}
 	}
 
+	// Multicast is available in encap/noEncap/hybrid mode.
 	if c.multicastEnabled && c.networkConfig.TrafficEncapMode.SupportsEncap() {
 		if err := c.ipset.CreateIPSet(clusterNodeIPSet, ipset.HashIP, false); err != nil {
 			return err
@@ -441,6 +445,7 @@ func (c *Client) syncIPSet() error {
 		})
 	}
 
+	// NodeNetworkPolicy is available in all traffic modes.
 	if c.nodeNetworkPolicyEnabled {
 		c.nodeNetworkPolicyIPSetsIPv4.Range(func(key, value any) bool {
 			ipsetName := key.(string)