diff --git a/linuxptp-classthreshold.patch b/linuxptp-classthreshold.patch
new file mode 100644
index 0000000..71b0250
--- /dev/null
+++ b/linuxptp-classthreshold.patch
@@ -0,0 +1,138 @@
+Backported commit f774703cb1eee058a346aec3341fee0be329bd6d
+Author: Karthikkumar V <kvaloor@altiostar.com>
+Date: Fri Feb 26 06:54:07 2021 +0000
+
+ Clock Class Threshold Feature addition for PTP4L
+
+ This code changes brings in the ability to program the acceptable
+ clockClass threshold beyond which device will move to holdover/free-run.
+ Default clockClass threshold is 248.
+ Example Use-Case:
+ This is needed in the cases where T-SC/T-BC Slave might want to listen
+ only on PRC clockCLass and anything beyond that might not be acceptible
+ and would want to go to holdover (with SyncE backup or internal oscillator).
+
+ Signed-off-by: Karthikkumar V <kvaloor@altiostar.com>
+ Signed-off-by: Ramana Reddy <rreddy@altiostar.com>
+
+diff --git a/clock.c b/clock.c
+index c1fcff6..d584748 100644
+--- a/clock.c
++++ b/clock.c
+@@ -114,6 +114,7 @@ struct clock {
+ int utc_offset;
+ int time_flags; /* grand master role */
+ int time_source; /* grand master role */
++ UInteger8 clock_class_threshold;
+ UInteger8 max_steps_removed;
+ enum servo_state servo_state;
+ enum timestamp_type timestamping;
+@@ -978,6 +979,7 @@ struct clock *clock_create(enum clock_type type, struct config *config,
+ c->default_dataset.localPriority =
+ config_get_int(config, NULL, "G.8275.defaultDS.localPriority");
+ c->max_steps_removed = config_get_int(config, NULL,"maxStepsRemoved");
++ c->clock_class_threshold = config_get_int(config, NULL, "clock_class_threshold");
+
+ /* Harmonize the twoStepFlag with the time_stamping option. */
+ if (config_harmonize_onestep(config)) {
+@@ -1711,6 +1713,11 @@ UInteger8 clock_max_steps_removed(struct clock *c)
+ return c->max_steps_removed;
+ }
+
++UInteger8 clock_get_clock_class_threshold(struct clock *c)
++{
++ return c->clock_class_threshold;
++}
++
+ UInteger16 clock_steps_removed(struct clock *c)
+ {
+ return c->cur.stepsRemoved;
+diff --git a/clock.h b/clock.h
+index e7daf97..845d54f 100644
+--- a/clock.h
++++ b/clock.h
+@@ -289,6 +289,13 @@ int clock_slave_only(struct clock *c);
+ */
+ UInteger8 clock_max_steps_removed(struct clock *c);
+
++/**
++ * Obtain the clock class threshold field from a clock's default data set.
++ * @param c The clock instance.
++ * @return Configured clock class threshold value.
++ */
++UInteger8 clock_get_clock_class_threshold(struct clock *c);
++
+ /**
+ * Obtain the steps removed field from a clock's current data set.
+ * @param c The clock instance.
+diff --git a/config.c b/config.c
+index c3deddb..bf1049f 100644
+--- a/config.c
++++ b/config.c
+@@ -231,6 +231,7 @@ struct config_item config_tab[] = {
+ GLOB_ITEM_INT("clockAccuracy", 0xfe, 0, UINT8_MAX),
+ GLOB_ITEM_INT("clockClass", 248, 0, UINT8_MAX),
+ GLOB_ITEM_STR("clockIdentity", "000000.0000.000000"),
++ GLOB_ITEM_INT("clock_class_threshold", CLOCK_CLASS_THRESHOLD_DEFAULT, 6, CLOCK_CLASS_THRESHOLD_DEFAULT),
+ GLOB_ITEM_ENU("clock_servo", CLOCK_SERVO_PI, clock_servo_enu),
+ GLOB_ITEM_ENU("clock_type", CLOCK_TYPE_ORDINARY, clock_type_enu),
+ GLOB_ITEM_ENU("dataset_comparison", DS_CMP_IEEE1588, dataset_comp_enu),
+diff --git a/configs/default.cfg b/configs/default.cfg
+index 9604219..b2ffa94 100644
+--- a/configs/default.cfg
++++ b/configs/default.cfg
+@@ -60,6 +60,7 @@ verbose 0
+ summary_interval 0
+ kernel_leap 1
+ check_fup_sync 0
++clock_class_threshold 248
+ #
+ # Servo Options
+ #
+diff --git a/ds.h b/ds.h
+index 9d9c417..dff6d5e 100644
+--- a/ds.h
++++ b/ds.h
+@@ -87,6 +87,7 @@ struct parent_ds {
+
+ #define CURRENT_UTC_OFFSET 37 /* 1 Jan 2017 */
+ #define INTERNAL_OSCILLATOR 0xA0
++#define CLOCK_CLASS_THRESHOLD_DEFAULT 248
+
+ struct timePropertiesDS {
+ Integer16 currentUtcOffset;
+diff --git a/port.c b/port.c
+index 2bb974c..eb3b319 100644
+--- a/port.c
++++ b/port.c
+@@ -1870,6 +1870,14 @@ int process_announce(struct port *p, struct ptp_message *m)
+ return result;
+ }
+
++ if (m->announce.grandmasterClockQuality.clockClass >
++ clock_get_clock_class_threshold(p->clock)) {
++ pl_err(60, "port %hu: Master clock quality received is "
++ "greater than configured, ignoring master!",
++ portnum(p));
++ return result;
++ }
++
+ switch (p->state) {
+ case PS_INITIALIZING:
+ case PS_FAULTY:
+diff --git a/ptp4l.8 b/ptp4l.8
+index b04936a..ca76175 100644
+--- a/ptp4l.8
++++ b/ptp4l.8
+@@ -455,6 +455,11 @@ message is greater than or equal to the value of maxStepsRemoved the
+ Announce message is not considered in the operation of the BMCA.
+ The default value is 255.
+ .TP
++.B clock_class_threshold
++The maximum clock class value from master, acceptible to sub-ordinate
++clock beyond which it moves out of lock state.
++The default value is 248.
++.TP
+
+ .B domainNumber
+ The domain attribute of the local clock.
diff --git a/linuxptp.spec b/linuxptp.spec
index 26dd879..cf7c8ae 100644
--- a/linuxptp.spec
+++ b/linuxptp.spec
@@ -23,6 +23,8 @@ Source11: https://github.com/mlichvar/clknetsim/archive/%{clknetsim_ver}/clknets
# don't repeat some log messages in multi-port configuration
Patch1: linuxptp-logmsgs.patch
+# add option to set clockClass threshold
+Patch2: linuxptp-classthreshold.patch
# limit unicast message rate per address and grant duration
Patch4: linuxptp-ucastrate.patch
# fix quoting in ptp4l man page
@@ -48,6 +50,7 @@ Supporting legacy APIs and other platforms is not a goal.
%prep
%setup -q -a 10 -a 11 -n %{name}-%{!?gitfullver:%{version}}%{?gitfullver}
%patch1 -p1 -b .logmsgs
+%patch2 -p1 -b .classthreshold
%patch4 -p1 -b .ucastrate
%patch7 -p1 -b .manfix
%patch8 -p1 -b .fclose
@@ -75,7 +78,8 @@ echo 'OPTIONS="-a -r"' > $RPM_BUILD_ROOT%{_sysconfdir}/sysconfig/phc2sys
echo '.so man8/ptp4l.8' > $RPM_BUILD_ROOT%{_mandir}/man5/ptp4l.conf.5
echo '.so man8/timemaster.8' > $RPM_BUILD_ROOT%{_mandir}/man5/timemaster.conf.5
-rm -f configs/snmpd.conf
+# Remove patch backup files and non-linuxptp configuration
+find configs -type f ! -name '*.cfg' -delete
%check
cd testsuite