diff --git a/backend/src/utilities/interface_bridge_helpers.py b/backend/src/utilities/interface_bridge_helpers.py
index 9443cd7..f2b9ac7 100644
--- a/backend/src/utilities/interface_bridge_helpers.py
+++ b/backend/src/utilities/interface_bridge_helpers.py
@@ -1,11 +1,15 @@
 from typing import Any, Dict, List, Optional
+import errno
 import logging
 import os
 import subprocess
+import time
 
 # ---- Logging ----------------------------------------------------------
 logger = logging.getLogger("af_packet_sniffer")
 _ETHTOOL_BIN = "/usr/sbin/ethtool" if os.path.exists("/usr/sbin/ethtool") else "ethtool"
+_ETHERNET_PROFILE_CACHE_TTL_SECONDS = 3.0
+_ETHERNET_PROFILE_CACHE: Dict[str, tuple[float, Dict[str, Any]]] = {}
 
 # -------------------------
 # Interface / bridge helpers
@@ -39,6 +43,12 @@ def _read_sysfs_text(path: str) -> Optional[str]:
             return f.read().strip()
     except FileNotFoundError:
         return None
+    except OSError as exc:
+        if exc.errno in {errno.EINVAL, errno.EIO, errno.ENODEV}:
+            logger.debug("Transient sysfs read failure for %s: %s", path, exc)
+            return None
+        logger.exception("Error reading sysfs path %s", path)
+        return None
     except Exception:
         logger.exception("Error reading sysfs path %s", path)
         return None
@@ -98,7 +108,7 @@ def read_interface_ethernet_profile(iface: str) -> Optional[Dict[str, Any]]:
             check=True,
         )
     except (FileNotFoundError, subprocess.CalledProcessError):
-        return None
+        return _get_cached_ethernet_profile(iface)
 
     values: dict[str, str] = {}
     for line in result.stdout.splitlines():
@@ -128,13 +138,29 @@ def read_interface_ethernet_profile(iface: str) -> Optional[Dict[str, Any]]:
             autoneg = lowered == "on"
 
     if speed_mbps is None and duplex is None and autoneg is None:
-        return None
+        return _get_cached_ethernet_profile(iface)
 
-    return {
+    profile = {
         "speed_mbps": speed_mbps,
         "duplex": duplex,
         "autoneg": autoneg,
     }
+    _ETHERNET_PROFILE_CACHE[iface] = (time.time(), profile)
+    return profile
+
+
+def _get_cached_ethernet_profile(iface: str) -> Optional[Dict[str, Any]]:
+    """Return a recent ethtool snapshot to smooth short renegotiation gaps."""
+    cached = _ETHERNET_PROFILE_CACHE.get(iface)
+    if cached is None:
+        return None
+
+    ts, profile = cached
+    if time.time() - ts > _ETHERNET_PROFILE_CACHE_TTL_SECONDS:
+        _ETHERNET_PROFILE_CACHE.pop(iface, None)
+        return None
+
+    return dict(profile)
 
 
 def _read_bridge_ports_from_sysfs(bridge: str) -> List[str]: