diff --git a/liteeth/core/__init__.py b/liteeth/core/__init__.py
index 26fc9f1..5eb68d4 100644
--- a/liteeth/core/__init__.py
+++ b/liteeth/core/__init__.py
@@ -15,18 +15,70 @@ from liteeth.core.icmp import LiteEthICMP
 
 class LiteEthIPCore(Module, AutoCSR):
     def __init__(self, phy, mac_address, ip_address, clk_freq, with_icmp=True, dw=8):
+        # Parameters.
+        # -----------
         ip_address = convert_ip(ip_address)
-        self.submodules.mac = LiteEthMAC(phy, dw, interface="crossbar", with_preamble_crc=True)
-        self.submodules.arp = LiteEthARP(self.mac, mac_address, ip_address, clk_freq, dw=dw)
-        self.submodules.ip  = LiteEthIP(self.mac, mac_address, ip_address, self.arp.table, dw=dw)
+
+        # MAC.
+        # ----
+        self.submodules.mac = LiteEthMAC(
+            phy       = phy,
+            dw        = dw,
+            interface = "crossbar",
+            with_preamble_crc = True,
+            with_sys_datapath = False,
+        )
+
+        # ARP.
+        # ----
+        self.submodules.arp = LiteEthARP(
+            mac         = self.mac,
+            mac_address = mac_address,
+            ip_address  = ip_address,
+            clk_freq    = clk_freq,
+            dw          = dw,
+        )
+
+        # IP.
+        # ---
+        self.submodules.ip  = LiteEthIP(
+            mac         = self.mac,
+            mac_address = mac_address,
+            ip_address  = ip_address,
+            arp_table   = self.arp.table,
+            dw          = dw,
+        )
+        # ICMP (Optional).
+        # ----------------
         if with_icmp:
-            self.submodules.icmp = LiteEthICMP(self.ip, ip_address, dw=dw)
+            self.submodules.icmp = LiteEthICMP(
+                ip         = self.ip,
+                ip_address = ip_address,
+                dw         = dw,
+            )
 
 # UDP IP Core --------------------------------------------------------------------------------------
 
 class LiteEthUDPIPCore(LiteEthIPCore):
     def __init__(self, phy, mac_address, ip_address, clk_freq, with_icmp=True, dw=8):
+        # Parameters.
+        # -----------
         ip_address = convert_ip(ip_address)
-        LiteEthIPCore.__init__(self, phy, mac_address, ip_address, clk_freq, dw=dw,
-                               with_icmp=with_icmp)
-        self.submodules.udp = LiteEthUDP(self.ip, ip_address, dw=dw)
+
+        # Core: MAC + ARP + IP + (ICMP).
+        # ------------------------------
+        LiteEthIPCore.__init__(self,
+            phy         = phy,
+            mac_address = mac_address,
+            ip_address  = ip_address,
+            clk_freq    = clk_freq,
+            dw          = dw,
+            with_icmp   = with_icmp
+        )
+        # UDP.
+        # ----
+        self.submodules.udp = LiteEthUDP(
+            ip         = self.ip,
+            ip_address = ip_address,
+            dw         = dw,
+        )