T2.3-T2.6: BWE guard, relay conformance Tier A/B/C, Prometheus metrics

crates/wzp-client/src/featherchat.rs

@@ -107,6 +107,7 @@ pub fn signal_to_call_type(signal: &SignalMessage) -> CallSignalType {
         SignalMessage::TransferAck => CallSignalType::Offer, // reuse
         SignalMessage::PresenceUpdate { .. } => CallSignalType::Offer, // reuse
         SignalMessage::RouteQuery { .. } => CallSignalType::Offer, // reuse
+        SignalMessage::TransportFeedback { .. } => CallSignalType::Offer, // reuse (BWE)
         SignalMessage::RouteResponse { .. } => CallSignalType::Offer, // reuse
         SignalMessage::SessionForward { .. } => CallSignalType::Offer, // reuse
         SignalMessage::SessionForwardAck { .. } => CallSignalType::Offer, // reuse

crates/wzp-proto/src/quality.rs

@@ -1,8 +1,10 @@
 //! See also: [`crate::dred_tuner`] for continuous DRED tuning within a tier.
 
 use std::collections::VecDeque;
+use std::sync::Arc;
 use std::time::{Duration, Instant};
 
+use crate::BandwidthEstimator;
 use crate::QualityProfile;
 use crate::packet::QualityReport;
 use crate::traits::QualityController;
@@ -134,6 +136,8 @@ pub struct AdaptiveQualityController {
     probe: Option<ProbeState>,
     /// Time spent stable at the current tier (for probe trigger).
     stable_since: Option<Instant>,
+    /// Optional bandwidth estimator for BWE-guarded upgrades.
+    bwe: Option<Arc<BandwidthEstimator>>,
 }
 
 /// Threshold for downgrading (fast reaction to degradation).
@@ -187,6 +191,7 @@ impl AdaptiveQualityController {
             fec_boost_amount: DEFAULT_FEC_BOOST,
             probe: None,
             stable_since: None,
+            bwe: None,
         }
     }
 
@@ -254,6 +259,17 @@ impl AdaptiveQualityController {
         self.stable_since = None;
     }
 
+    /// Attach a bandwidth estimator for BWE-guarded tier transitions.
+    pub fn set_bandwidth_estimator(&mut self, bwe: Arc<BandwidthEstimator>) {
+        self.bwe = Some(bwe);
+    }
+
+    /// Return the bitrate ceiling (in bps) for a given tier, including FEC overhead.
+    fn tier_ceiling_bps(tier: Tier) -> u64 {
+        let kbps = tier.profile().total_bitrate_kbps();
+        (kbps * 1000.0) as u64
+    }
+
     /// Get the effective downgrade threshold based on network context.
     fn downgrade_threshold(&self) -> u32 {
         match self.network_context {
@@ -296,6 +312,15 @@ impl AdaptiveQualityController {
             if self.consecutive_up >= threshold {
                 // Only upgrade one step at a time
                 if let Some(next_tier) = self.upgrade_one_step() {
+                    // BWE guard: require 130% headroom over target tier bitrate
+                    if let Some(ref bwe) = self.bwe {
+                        let required = (Self::tier_ceiling_bps(next_tier) * 130) / 100;
+                        if bwe.target_send_bps() < required {
+                            // Insufficient bandwidth — reset counter to prevent flapping
+                            self.consecutive_up = 0;
+                            return None;
+                        }
+                    }
                     self.current_tier = next_tier;
                     self.current_profile = next_tier.profile();
                     self.consecutive_up = 0;
@@ -529,6 +554,53 @@ mod tests {
         }
     }
 
+    #[test]
+    fn bwe_guard_blocks_upgrade_when_bandwidth_insufficient() {
+        let mut ctrl = AdaptiveQualityController::new();
+
+        // Force to catastrophic
+        let bad = make_report(50.0, 300);
+        for _ in 0..3 {
+            ctrl.observe(&bad);
+        }
+        assert_eq!(ctrl.tier(), Tier::Catastrophic);
+
+        // Attach a BWE with very low headroom.
+        // Degraded tier needs 6kbps * 1.5 FEC = 9kbps → 130% = 11.7kbps.
+        // Set target_send_bps ≈ 9_000 (below 11_700 threshold).
+        let bwe = Arc::new(BandwidthEstimator::new(1000.0, 1.0, 100_000.0));
+        bwe.update_from_path(1_000_000, 0, 10); // high cwnd
+        bwe.update_from_peer(10_000); // low remb → target = 9_000
+        ctrl.set_bandwidth_estimator(bwe.clone());
+
+        let good = make_report(0.5, 20);
+        for _ in 0..5 {
+            assert!(
+                ctrl.observe(&good).is_none(),
+                "upgrade should be blocked by low BWE"
+            );
+        }
+        assert_eq!(
+            ctrl.tier(),
+            Tier::Catastrophic,
+            "should remain at Catastrophic"
+        );
+
+        // Raise BWE well above the 130% threshold
+        bwe.update_from_peer(100_000); // target ≈ 90_000 bps
+
+        // Counter was reset, need another 5 good reports
+        for _ in 0..4 {
+            assert!(ctrl.observe(&good).is_none());
+        }
+        let result = ctrl.observe(&good);
+        assert!(
+            result.is_some(),
+            "upgrade should proceed with sufficient BWE"
+        );
+        assert_eq!(ctrl.tier(), Tier::Degraded);
+    }
+
     #[test]
     fn tier_classification() {
         // Studio tiers

crates/wzp-relay/src/conformance.rs

@@ -0,0 +1,315 @@
+//! Relay conformance metering — Tier A/B/C enforcement.
+//!
+//! Each participant gets a [`ConformanceMeter`] that tracks per-second
+//! traffic against the declared codec's nominal bitrate ceiling.
+//! Violations are logged and counted but do **not** drop packets
+//! (observe-only mode).
+
+use std::collections::VecDeque;
+use std::time::{Duration, Instant};
+use wzp_proto::{CodecId, MediaHeader};
+
+/// Rolling window size for timestamp-drift detection (Tier C).
+const DRIFT_WINDOW_SIZE: usize = 200;
+
+/// Kinds of conformance violation detected by the relay.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Violation {
+    /// Cumulative bitrate in the current 1 s window exceeds the Tier A ceiling.
+    BitrateExceeded,
+    /// Packet rate exceeds the per-codec safety limit (Tier B).
+    PacketRateExceeded,
+    /// Timestamp jumped backwards or forwards suspiciously (Tier C).
+    TimestampDrift,
+}
+
+/// Per-participant traffic conformance meter.
+pub struct ConformanceMeter {
+    window_start: Instant,
+    bytes_in_window: u64,
+    packets_in_window: u64,
+    /// Rolling (seq, timestamp) pairs for drift detection.
+    drift_window: VecDeque<(u32, u32)>,
+}
+
+impl ConformanceMeter {
+    pub fn new() -> Self {
+        Self {
+            window_start: Instant::now(),
+            bytes_in_window: 0,
+            packets_in_window: 0,
+            drift_window: VecDeque::with_capacity(DRIFT_WINDOW_SIZE),
+        }
+    }
+
+    /// Inspect an incoming media packet and accumulate it against the
+    /// current 1-second window. Returns [`Err(Violation)`] when a limit
+    /// is crossed.
+    pub fn observe(
+        &mut self,
+        header: &MediaHeader,
+        payload_len: usize,
+        now: Instant,
+    ) -> Result<(), Violation> {
+        // Roll the window forward if a second has elapsed.
+        if now.duration_since(self.window_start) >= Duration::from_secs(1) {
+            self.window_start = now;
+            self.bytes_in_window = 0;
+            self.packets_in_window = 0;
+        }
+
+        let packet_size = (MediaHeader::WIRE_SIZE + payload_len) as u64;
+        self.bytes_in_window += packet_size;
+        self.packets_in_window += 1;
+
+        // Tier A — bitrate ceiling.
+        let ceiling = ceiling_bps(header.codec_id);
+        let max_bytes_per_sec = ceiling / 8;
+        if self.bytes_in_window > max_bytes_per_sec {
+            return Err(Violation::BitrateExceeded);
+        }
+
+        // Tier B — packet-rate ceiling.
+        let max_pps = max_pps(header.codec_id);
+        let pps_threshold = (max_pps as f32 * 1.5) as u64;
+        if self.packets_in_window > pps_threshold {
+            return Err(Violation::PacketRateExceeded);
+        }
+
+        // Tier C — timestamp drift.
+        self.drift_window.push_back((header.seq, header.timestamp));
+        if self.drift_window.len() > DRIFT_WINDOW_SIZE {
+            self.drift_window.pop_front();
+        }
+        if self.drift_window.len() >= 2 {
+            let (first_seq, first_ts) = self.drift_window.front().copied().unwrap();
+            let (last_seq, last_ts) = self.drift_window.back().copied().unwrap();
+
+            let ds = last_seq.wrapping_sub(first_seq) as f64;
+            let dt = last_ts.wrapping_sub(first_ts) as f64;
+
+            if ds > 0.0 {
+                let avg_ms_per_packet = dt / ds;
+                let frame_ms = header.codec_id.frame_duration_ms() as f64;
+                let min_ratio = frame_ms * 0.5;
+                let max_ratio = frame_ms * 2.0;
+                if avg_ms_per_packet < min_ratio || avg_ms_per_packet > max_ratio {
+                    return Err(Violation::TimestampDrift);
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl Default for ConformanceMeter {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Compute the Tier A bitrate ceiling for a given codec.
+///
+/// Formula:
+///   nominal_bitrate * 3 (FEC 2.0 overhead) * 115 / 100 (15% safety margin)
+/// with a floor of 2 kbps.
+pub fn ceiling_bps(codec: CodecId) -> u64 {
+    let nominal = codec.bitrate_bps() as u64;
+    (nominal * 3 * 115 / 100).max(2_000)
+}
+
+/// Compute the Tier B packet-rate ceiling for a given codec.
+///
+/// Formula:
+///   1000 / frame_duration_ms * 3 (FEC overhead factor)
+pub fn max_pps(codec: CodecId) -> u32 {
+    let fd = codec.frame_duration_ms() as u32;
+    if fd == 0 {
+        return 0;
+    }
+    (1000 / fd) * 3
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use wzp_proto::MediaType;
+
+    fn make_header(codec_id: CodecId) -> MediaHeader {
+        MediaHeader {
+            version: 2,
+            flags: 0,
+            media_type: MediaType::Audio,
+            codec_id,
+            seq: 0,
+            timestamp: 0,
+            fec_block: 0,
+            stream_id: 0,
+            fec_ratio: 0,
+        }
+    }
+
+    fn make_header_with_seq_ts(codec_id: CodecId, seq: u32, timestamp: u32) -> MediaHeader {
+        MediaHeader {
+            version: 2,
+            flags: 0,
+            media_type: MediaType::Audio,
+            codec_id,
+            seq,
+            timestamp,
+            fec_block: 0,
+            stream_id: 0,
+            fec_ratio: 0,
+        }
+    }
+
+    #[test]
+    fn bitrate_exceeded_for_opus24k() {
+        let mut meter = ConformanceMeter::new();
+        let header = make_header(CodecId::Opus24k);
+
+        // Ceiling for Opus24k = 24_000 * 3 * 115 / 100 = 82_800 bps
+        // = 10_350 bytes/sec.  1 MB/s = 125_000 bytes/packet will blow past
+        // that in a single packet.
+        let now = Instant::now();
+        let result = meter.observe(&header, 1_000_000, now);
+        assert_eq!(result, Err(Violation::BitrateExceeded));
+    }
+
+    #[test]
+    fn small_packets_stay_within_ceiling() {
+        let mut meter = ConformanceMeter::new();
+        let header = make_header(CodecId::Opus24k);
+
+        // Ceiling = 82_800 bps = 10_350 bytes/sec.
+        // Each packet = 16-byte header + 80 bytes = 96 bytes.
+        // 100 packets = 9_600 bytes < 10_350.
+        let now = Instant::now();
+        for _ in 0..100 {
+            assert!(meter.observe(&header, 80, now).is_ok());
+        }
+    }
+
+    #[test]
+    fn window_resets_after_one_second() {
+        let mut meter = ConformanceMeter::new();
+        let header = make_header(CodecId::Opus24k);
+
+        // Fill the window to just under the limit.
+        let t0 = Instant::now();
+        for _ in 0..10 {
+            assert!(meter.observe(&header, 1000, t0).is_ok());
+        }
+        // 10 * (header wire size + 1000) ≈ 10 * 1034 = 10_340 bytes < 10_350
+
+        // Same packets 1.1 seconds later should be fine because the window
+        // rolls over.
+        let t1 = t0 + Duration::from_millis(1_100);
+        for _ in 0..10 {
+            assert!(meter.observe(&header, 1000, t1).is_ok());
+        }
+    }
+
+    #[test]
+    fn ceiling_bps_floor() {
+        // ComfortNoise has 0 nominal bitrate, so the floor kicks in.
+        assert_eq!(ceiling_bps(CodecId::ComfortNoise), 2_000);
+    }
+
+    // ------------------------------------------------------------------
+    // Tier B — packet rate
+    // ------------------------------------------------------------------
+
+    #[test]
+    fn packet_rate_exceeded() {
+        let mut meter = ConformanceMeter::new();
+        // Opus24k: max_pps = 1000/20 * 3 = 150. Threshold = 150 * 1.5 = 225.
+        let header = make_header(CodecId::Opus24k);
+        let now = Instant::now();
+        for _ in 0..225 {
+            assert!(meter.observe(&header, 10, now).is_ok());
+        }
+        // 226th packet should trip the limit.
+        assert_eq!(
+            meter.observe(&header, 10, now),
+            Err(Violation::PacketRateExceeded)
+        );
+    }
+
+    #[test]
+    fn packet_rate_within_limit() {
+        let mut meter = ConformanceMeter::new();
+        // Opus6k: max_pps = 1000/40 * 3 = 75. Threshold = 75 * 1.5 = 112.
+        // Use 0-byte payload so bitrate ceiling (2_587 bytes/sec) is not the
+        // limiting factor. 112 packets × 16 bytes = 1_792 bytes < 2_587.
+        let header = make_header(CodecId::Opus6k);
+        let now = Instant::now();
+        for _ in 0..112 {
+            assert!(meter.observe(&header, 0, now).is_ok());
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Tier C — timestamp drift
+    // ------------------------------------------------------------------
+
+    #[test]
+    fn timestamp_drift_detected_when_too_fast() {
+        let mut meter = ConformanceMeter::new();
+        // Opus24k frame_duration = 20 ms.
+        // Acceptable range: [10, 40] ms per packet.
+        // Send packets with timestamp advancing by 5 ms each (too fast).
+        let now = Instant::now();
+        let mut drift_seen = false;
+        for i in 0..200 {
+            let header = make_header_with_seq_ts(CodecId::Opus24k, i, i * 5);
+            match meter.observe(&header, 10, now) {
+                Ok(()) => {}
+                Err(Violation::TimestampDrift) => drift_seen = true,
+                Err(other) => panic!("unexpected violation: {other:?}"),
+            }
+        }
+        assert!(drift_seen, "expected TimestampDrift to be detected");
+    }
+
+    #[test]
+    fn timestamp_drift_detected_when_too_slow() {
+        let mut meter = ConformanceMeter::new();
+        // Opus24k frame_duration = 20 ms.
+        // Acceptable range: [10, 40] ms per packet.
+        // Send packets with timestamp advancing by 50 ms each (too slow).
+        let now = Instant::now();
+        let mut drift_seen = false;
+        for i in 0..200 {
+            let header = make_header_with_seq_ts(CodecId::Opus24k, i, i * 50);
+            match meter.observe(&header, 10, now) {
+                Ok(()) => {}
+                Err(Violation::TimestampDrift) => drift_seen = true,
+                Err(other) => panic!("unexpected violation: {other:?}"),
+            }
+        }
+        assert!(drift_seen, "expected TimestampDrift to be detected");
+    }
+
+    #[test]
+    fn timestamp_normal_no_drift() {
+        let mut meter = ConformanceMeter::new();
+        // Opus24k frame_duration = 20 ms.
+        // Send 200 packets with timestamp advancing by exactly 20 ms each.
+        let now = Instant::now();
+        for i in 0..200 {
+            let header = make_header_with_seq_ts(CodecId::Opus24k, i, i * 20);
+            assert!(meter.observe(&header, 10, now).is_ok());
+        }
+    }
+
+    #[test]
+    fn timestamp_drift_not_checked_before_two_packets() {
+        let mut meter = ConformanceMeter::new();
+        let now = Instant::now();
+        // Single packet with wild timestamp — should not trigger drift.
+        let header = make_header_with_seq_ts(CodecId::Opus24k, 0, 999_999);
+        assert!(meter.observe(&header, 10, now).is_ok());
+    }
+}

crates/wzp-relay/src/lib.rs

@@ -10,6 +10,7 @@
 pub mod auth;
 pub mod call_registry;
 pub mod config;
+pub mod conformance;
 pub mod event_log;
 pub mod federation;
 pub mod handshake;

crates/wzp-relay/src/metrics.rs

@@ -1,12 +1,15 @@
 //! Prometheus metrics for the WZP relay daemon.
 
 use prometheus::{
-    Encoder, GaugeVec, Histogram, HistogramOpts, IntCounter, IntCounterVec, IntGauge, IntGaugeVec,
-    Opts, Registry, TextEncoder,
+    Encoder, GaugeVec, Histogram, HistogramOpts, HistogramVec, IntCounter, IntCounterVec, IntGauge,
+    IntGaugeVec, Opts, Registry, TextEncoder,
 };
 use std::sync::Arc;
+use wzp_proto::MediaHeader;
 use wzp_proto::packet::QualityReport;
 
+use crate::conformance::Violation;
+
 /// All relay-level Prometheus metrics.
 #[derive(Clone)]
 pub struct RelayMetrics {
@@ -32,6 +35,9 @@ pub struct RelayMetrics {
     // Phase 4: loss-recovery breakdown per session.
     pub session_dred_reconstructions: IntCounterVec,
     pub session_classical_plc: IntCounterVec,
+    pub conformance_violations: IntCounterVec,
+    pub conformance_bytes: HistogramVec,
+    pub conformance_iat_ms: HistogramVec,
     registry: Registry,
 }
 
@@ -168,6 +174,37 @@ impl RelayMetrics {
             &["session_id"],
         )
         .expect("metric");
+        let conformance_violations = IntCounterVec::new(
+            Opts::new(
+                "wzp_relay_conformance_violations_total",
+                "Conformance violations by tier, codec, media type and verdict",
+            ),
+            &["tier", "codec_id", "media_type", "verdict"],
+        )
+        .expect("metric");
+        let conformance_bytes = HistogramVec::new(
+            HistogramOpts::new(
+                "wzp_relay_conformance_bytes_per_session",
+                "Packet size distribution observed by the conformance meter",
+            )
+            .buckets(vec![
+                16.0, 32.0, 64.0, 128.0, 256.0, 512.0, 1024.0, 2048.0, 4096.0, 8192.0, 16384.0,
+                32768.0, 65536.0,
+            ]),
+            &["media_type"],
+        )
+        .expect("metric");
+        let conformance_iat_ms = HistogramVec::new(
+            HistogramOpts::new(
+                "wzp_relay_conformance_iat_ms",
+                "Inter-arrival time distribution in milliseconds",
+            )
+            .buckets(vec![
+                1.0, 5.0, 10.0, 20.0, 30.0, 40.0, 60.0, 80.0, 100.0, 150.0, 200.0, 300.0, 500.0,
+            ]),
+            &["media_type"],
+        )
+        .expect("metric");
 
         registry
             .register(Box::new(active_sessions.clone()))
@@ -226,6 +263,15 @@ impl RelayMetrics {
         registry
             .register(Box::new(session_classical_plc.clone()))
             .expect("register");
+        registry
+            .register(Box::new(conformance_violations.clone()))
+            .expect("register");
+        registry
+            .register(Box::new(conformance_bytes.clone()))
+            .expect("register");
+        registry
+            .register(Box::new(conformance_iat_ms.clone()))
+            .expect("register");
 
         Self {
             active_sessions,
@@ -247,6 +293,9 @@ impl RelayMetrics {
             session_overruns,
             session_dred_reconstructions,
             session_classical_plc,
+            conformance_violations,
+            conformance_bytes,
+            conformance_iat_ms,
             registry,
         }
     }
@@ -328,6 +377,43 @@ impl RelayMetrics {
         }
     }
 
+    /// Record conformance-related metrics for a single received packet.
+    ///
+    /// * `header` — the media header (provides codec_id and media_type).
+    /// * `payload_len` — payload length in bytes.
+    /// * `iat_ms` — inter-arrival time since the previous packet.
+    /// * `violation` — `Some(Violation)` if the packet triggered a conformance
+    ///   limit; `None` for clean packets.
+    pub fn record_conformance(
+        &self,
+        header: &MediaHeader,
+        payload_len: usize,
+        iat_ms: u64,
+        violation: Option<Violation>,
+    ) {
+        let media_type = format!("{:?}", header.media_type);
+        let bytes = (MediaHeader::WIRE_SIZE + payload_len) as f64;
+        self.conformance_bytes
+            .with_label_values(&[&media_type])
+            .observe(bytes);
+        self.conformance_iat_ms
+            .with_label_values(&[&media_type])
+            .observe(iat_ms as f64);
+
+        if let Some(v) = violation {
+            let tier = match v {
+                Violation::BitrateExceeded => "A",
+                Violation::PacketRateExceeded => "B",
+                Violation::TimestampDrift => "C",
+            };
+            let codec_id = format!("{:?}", header.codec_id);
+            let verdict = format!("{:?}", v);
+            self.conformance_violations
+                .with_label_values(&[tier, &codec_id, &media_type, &verdict])
+                .inc();
+        }
+    }
+
     /// Remove all per-session label values for a disconnected session.
     pub fn remove_session_metrics(&self, session_id: &str) {
         let _ = self.session_buffer_depth.remove_label_values(&[session_id]);

crates/wzp-relay/src/room.rs

@@ -17,6 +17,7 @@ use wzp_proto::packet::TrunkFrame;
 use wzp_proto::quality::{AdaptiveQualityController, Tier};
 use wzp_proto::traits::QualityController;
 
+use crate::conformance::ConformanceMeter;
 use crate::metrics::RelayMetrics;
 use crate::trunk::TrunkBatcher;
 
@@ -780,6 +781,7 @@ async fn run_participant_plain(
     let mut max_forward_ms = 0u64;
     let mut send_errors = 0u64;
     let mut last_log_instant = std::time::Instant::now();
+    let mut conformance = ConformanceMeter::new();
 
     let mut tap_stats = if debug_tap.as_ref().map_or(false, |t| t.matches(&room_name)) {
         Some(TapStats::new())
@@ -829,6 +831,22 @@ async fn run_participant_plain(
             );
         }
 
+        // Conformance check (Tier A/B/C — observe-only)
+        let violation = conformance
+            .observe(&pkt.header, pkt.payload.len(), std::time::Instant::now())
+            .err();
+        metrics.record_conformance(&pkt.header, pkt.payload.len(), recv_gap_ms, violation);
+        if let Some(v) = violation {
+            warn!(
+                room = %room_name,
+                participant = participant_id,
+                codec = ?pkt.header.codec_id,
+                seq = pkt.header.seq,
+                violation = ?v,
+                "conformance violation"
+            );
+        }
+
         // Update per-session quality metrics if a quality report is present
         if let Some(ref report) = pkt.quality_report {
             metrics.update_session_quality(session_id, report);
@@ -998,6 +1016,7 @@ async fn run_participant_trunked(
     let mut max_forward_ms = 0u64;
     let mut send_errors = 0u64;
     let mut last_log_instant = std::time::Instant::now();
+    let mut conformance = ConformanceMeter::new();
 
     info!(
         room = %room_name,
@@ -1051,6 +1070,22 @@ async fn run_participant_trunked(
                     );
                 }
 
+                // Conformance check (Tier A/B/C — observe-only)
+                let violation = conformance
+                    .observe(&pkt.header, pkt.payload.len(), std::time::Instant::now())
+                    .err();
+                metrics.record_conformance(&pkt.header, pkt.payload.len(), recv_gap_ms, violation);
+                if let Some(v) = violation {
+                    warn!(
+                        room = %room_name,
+                        participant = participant_id,
+                        codec = ?pkt.header.codec_id,
+                        seq = pkt.header.seq,
+                        violation = ?v,
+                        "conformance violation (trunked)"
+                    );
+                }
+
                 if let Some(ref report) = pkt.quality_report {
                     metrics.update_session_quality(session_id, report);
                 }