From 0fdb37bd11a0d71c26606ca4e76bbf4d787ed88d Mon Sep 17 00:00:00 2001
From: Raphael Riebl <raphael.riebl@nfiniity.com>
Date: Thu, 4 Jul 2024 10:34:56 +0200
Subject: [PATCH] geonet: configurable initial beacon delay

---
 vanetza/geonet/mib.cpp    |  2 +-
 vanetza/geonet/mib.hpp    |  2 +-
 vanetza/geonet/router.cpp | 12 ++++++------
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/vanetza/geonet/mib.cpp b/vanetza/geonet/mib.cpp
index 1c96b092d..6355d66a6 100644
--- a/vanetza/geonet/mib.cpp
+++ b/vanetza/geonet/mib.cpp
@@ -50,7 +50,7 @@ ManagementInformationBase::ManagementInformationBase() :
     itsGnDefaultTrafficClass(false, false, 0),
     vanetzaDefaultSeed(0xc0114c2c),
     vanetzaCbfMaxCounter(1),
-    vanetzaDeferInitialBeacon(false),
+    vanetzaDeferInitialBeacon(Clock::duration::zero()),
     vanetzaDisableBeaconing(false),
     vanetzaMultiHopDuplicateAddressDetection(false),
     vanetzaFadingCbfCounter(false),
diff --git a/vanetza/geonet/mib.hpp b/vanetza/geonet/mib.hpp
index 99e293a37..00c48cf23 100644
--- a/vanetza/geonet/mib.hpp
+++ b/vanetza/geonet/mib.hpp
@@ -94,7 +94,7 @@ struct ManagementInformationBase
     TrafficClass itsGnDefaultTrafficClass;
     std::uint32_t vanetzaDefaultSeed; /*< default seed for internal random number generator */
     std::size_t vanetzaCbfMaxCounter; /*< maximum counter value used for Advanced routing */
-    bool vanetzaDeferInitialBeacon; /*< defer first beacon up to itsGnBeaconServiceRetransmitTimer */
+    Clock::duration vanetzaDeferInitialBeacon; /*< defer first beacon by given duration */
     bool vanetzaDisableBeaconing; /*< disable transmission of beacons entirely */
     bool vanetzaMultiHopDuplicateAddressDetection; /*< execute DAD for multi-hop packets */
     bool vanetzaFadingCbfCounter; /*< use fading counters for CBF packet buffer */
diff --git a/vanetza/geonet/router.cpp b/vanetza/geonet/router.cpp
index 6e87262f7..e1e557571 100644
--- a/vanetza/geonet/router.cpp
+++ b/vanetza/geonet/router.cpp
@@ -145,14 +145,14 @@ Router::Router(Runtime& rt, const MIB& mib) :
     m_random_gen(mib.vanetzaDefaultSeed)
 {
     if (!m_mib.vanetzaDisableBeaconing) {
-        if (!m_mib.vanetzaDeferInitialBeacon) {
+        if (m_mib.vanetzaDeferInitialBeacon > Clock::duration::zero()) {
+            // defer initial Beacon transmission by given duration plus jitter
+            std::uniform_real_distribution<double> dist_jitter(0.0, 1.0);
+            const auto jitter = clock_cast(dist_jitter(m_random_gen) * m_mib.itsGnBeaconServiceMaxJitter);
+            reset_beacon_timer(m_mib.vanetzaDeferInitialBeacon + jitter);
+        } else {
             // send Beacon immediately after start-up at next runtime trigger invocation
             reset_beacon_timer(Clock::duration::zero());
-        } else {
-            // defer initial Beacon transmission slightly
-            std::uniform_real_distribution<double> dist(0.0, 1.0);
-            const auto first_beacon = dist(m_random_gen) * m_mib.itsGnBeaconServiceRetransmitTimer;
-            reset_beacon_timer(clock_cast(first_beacon));
         }
     }