diff --git a/README.md b/README.md
index fa04115..b62cab9 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,2 @@
 # tutorials
-Holds different P4 language tutorials
+P4 language tutorials
diff --git a/SIGCOMM_2015/flowlet_switching/commands.txt b/SIGCOMM_2015/flowlet_switching/commands.txt
new file mode 100644
index 0000000..7c0e3ae
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/commands.txt
@@ -0,0 +1,11 @@
+table_set_default ecmp_group _drop
+table_set_default ecmp_nhop _drop
+table_set_default forward _drop
+table_set_default send_frame _drop
+table_add ecmp_group set_ecmp_select 10.0.0.1/32 => 0 2
+table_add ecmp_nhop set_nhop 0 => 10.0.1.1 1
+table_add ecmp_nhop set_nhop 1 => 10.0.2.1 2
+table_add forward set_dmac 10.0.1.1 => 00:04:00:00:00:00
+table_add forward set_dmac 10.0.2.1 => 00:04:00:00:00:01
+table_add send_frame rewrite_mac 1 => 00:aa:bb:00:00:00
+table_add send_frame rewrite_mac 2 => 00:aa:bb:00:00:01
diff --git a/SIGCOMM_2015/flowlet_switching/p4src/includes/headers.p4 b/SIGCOMM_2015/flowlet_switching/p4src/includes/headers.p4
new file mode 100644
index 0000000..b9b0725
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/p4src/includes/headers.p4
@@ -0,0 +1,56 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+header_type ethernet_t {
+    fields {
+        dstAddr : 48;
+        srcAddr : 48;
+        etherType : 16;
+    }
+}
+
+header_type ipv4_t {
+    fields {
+        version : 4;
+        ihl : 4;
+        diffserv : 8;
+        totalLen : 16;
+        identification : 16;
+        flags : 3;
+        fragOffset : 13;
+        ttl : 8;
+        protocol : 8;
+        hdrChecksum : 16;
+        srcAddr : 32;
+        dstAddr: 32;
+    }
+}
+
+header_type tcp_t {
+    fields {
+        srcPort : 16;
+        dstPort : 16;
+        seqNo : 32;
+        ackNo : 32;
+        dataOffset : 4;
+        res : 3;
+        ecn : 3;
+        ctrl : 6;
+        window : 16;
+        checksum : 16;
+        urgentPtr : 16;
+    }
+}
diff --git a/SIGCOMM_2015/flowlet_switching/p4src/includes/intrinsic.p4 b/SIGCOMM_2015/flowlet_switching/p4src/includes/intrinsic.p4
new file mode 100644
index 0000000..1785cd0
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/p4src/includes/intrinsic.p4
@@ -0,0 +1,26 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+header_type intrinsic_metadata_t {
+    fields {
+        ingress_global_timestamp : 48;
+        lf_field_list : 32;
+        mcast_grp : 16;
+        egress_rid : 16;
+    }
+}
+
+metadata intrinsic_metadata_t intrinsic_metadata;
diff --git a/SIGCOMM_2015/flowlet_switching/p4src/includes/parser.p4 b/SIGCOMM_2015/flowlet_switching/p4src/includes/parser.p4
new file mode 100644
index 0000000..6d92708
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/p4src/includes/parser.p4
@@ -0,0 +1,77 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+parser start {
+    return parse_ethernet;
+}
+
+#define ETHERTYPE_IPV4 0x0800
+
+header ethernet_t ethernet;
+
+parser parse_ethernet {
+    extract(ethernet);
+    return select(latest.etherType) {
+        ETHERTYPE_IPV4 : parse_ipv4;
+        default: ingress;
+    }
+}
+
+header ipv4_t ipv4;
+
+field_list ipv4_checksum_list {
+        ipv4.version;
+        ipv4.ihl;
+        ipv4.diffserv;
+        ipv4.totalLen;
+        ipv4.identification;
+        ipv4.flags;
+        ipv4.fragOffset;
+        ipv4.ttl;
+        ipv4.protocol;
+        ipv4.srcAddr;
+        ipv4.dstAddr;
+}
+
+field_list_calculation ipv4_checksum {
+    input {
+        ipv4_checksum_list;
+    }
+    algorithm : csum16;
+    output_width : 16;
+}
+
+calculated_field ipv4.hdrChecksum  {
+    verify ipv4_checksum;
+    update ipv4_checksum;
+}
+
+#define IP_PROTOCOLS_TCP 6
+
+parser parse_ipv4 {
+    extract(ipv4);
+    return select(latest.protocol) {
+        IP_PROTOCOLS_TCP : parse_tcp;
+        default: ingress;
+    }
+}
+
+header tcp_t tcp;
+
+parser parse_tcp {
+    extract(tcp);
+    return ingress;
+}
diff --git a/SIGCOMM_2015/flowlet_switching/p4src/simple_router.p4 b/SIGCOMM_2015/flowlet_switching/p4src/simple_router.p4
new file mode 100644
index 0000000..2df930c
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/p4src/simple_router.p4
@@ -0,0 +1,132 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include "includes/headers.p4"
+#include "includes/parser.p4"
+#include "includes/intrinsic.p4"
+
+header_type ingress_metadata_t {
+    fields {
+        ecmp_offset : 14; // offset into the ecmp table
+
+        nhop_ipv4 : 32;
+
+        // TODO: add your flowlet metadata here
+    }
+}
+
+metadata ingress_metadata_t ingress_metadata;
+
+action _drop() {
+    drop();
+}
+
+action set_nhop(nhop_ipv4, port) {
+    modify_field(ingress_metadata.nhop_ipv4, nhop_ipv4);
+    modify_field(standard_metadata.egress_spec, port);
+    add_to_field(ipv4.ttl, -1);
+}
+
+#define ECMP_BIT_WIDTH 10
+#define ECMP_GROUP_TABLE_SIZE 1024
+#define ECMP_NHOP_TABLE_SIZE 16384
+
+// TODO: add flowlet id to hash fields
+
+field_list l3_hash_fields {
+    ipv4.srcAddr;
+    ipv4.dstAddr;
+    ipv4.protocol;
+    tcp.srcPort;
+    tcp.dstPort;
+}
+
+field_list_calculation ecmp_hash {
+    input {
+        l3_hash_fields;
+    }
+    algorithm : crc16;
+    output_width : ECMP_BIT_WIDTH;
+}
+
+
+action set_ecmp_select(ecmp_base, ecmp_count) {
+    modify_field_with_hash_based_offset(ingress_metadata.ecmp_offset, ecmp_base,
+                                        ecmp_hash, ecmp_count);
+}
+
+table ecmp_group {
+    reads {
+        ipv4.dstAddr : lpm;
+    }
+    actions {
+        _drop;
+        set_ecmp_select;
+    }
+    size : ECMP_GROUP_TABLE_SIZE;
+}
+
+table ecmp_nhop {
+    reads {
+        ingress_metadata.ecmp_offset : exact;
+    }
+    actions {
+        _drop;
+        set_nhop;
+    }
+    size : ECMP_NHOP_TABLE_SIZE;
+}
+
+action set_dmac(dmac) {
+    modify_field(ethernet.dstAddr, dmac);
+}
+
+table forward {
+    reads {
+        ingress_metadata.nhop_ipv4 : exact;
+    }
+    actions {
+        set_dmac;
+        _drop;
+    }
+    size: 512;
+}
+
+action rewrite_mac(smac) {
+    modify_field(ethernet.srcAddr, smac);
+}
+
+table send_frame {
+    reads {
+        standard_metadata.egress_port: exact;
+    }
+    actions {
+        rewrite_mac;
+        _drop;
+    }
+    size: 256;
+}
+
+control ingress {
+    // TODO: flowlet switching
+    apply(ecmp_group);
+    apply(ecmp_nhop);
+    apply(forward);
+}
+
+control egress {
+    apply(send_frame);
+}
diff --git a/SIGCOMM_2015/flowlet_switching/run_demo.sh b/SIGCOMM_2015/flowlet_switching/run_demo.sh
new file mode 100755
index 0000000..25bf7f6
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/run_demo.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+
+# Copyright 2013-present Barefoot Networks, Inc. 
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+
+source $THIS_DIR/../env.sh
+
+P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
+
+SWITCH_PATH=$BMV2_PATH/targets/simple_switch/simple_switch
+
+CLI_PATH=$BMV2_PATH/tools/runtime_CLI.py
+
+# Probably not very elegant but it works nice here: we enable interactive mode
+# to be able to use fg. We start the switch in the background, sleep for 2
+# minutes to give it time to start, then add the entries and put the switch
+# process back in the foreground
+set -m
+$P4C_BM_SCRIPT p4src/simple_router.p4 --json simple_router.json
+sudo echo "sudo" > /dev/null
+sudo $BMV2_PATH/targets/simple_switch/simple_switch simple_router.json \
+    -i 0@veth0 -i 1@veth2 -i 2@veth4 -i 3@veth6 -i 4@veth8 \
+    --nanolog ipc:///tmp/bm-0-log.ipc \
+    --pcap &
+sleep 2
+$CLI_PATH --json simple_router.json < commands.txt
+echo "READY!!!"
+fg
diff --git a/SIGCOMM_2015/flowlet_switching/run_test.py b/SIGCOMM_2015/flowlet_switching/run_test.py
new file mode 100755
index 0000000..5e09682
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/run_test.py
@@ -0,0 +1,135 @@
+#!/usr/bin/env python
+
+# Copyright 2013-present Barefoot Networks, Inc. 
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import time
+
+NUM_PACKETS = 500
+
+import random
+
+import threading
+from scapy.all import sniff
+from scapy.all import Ether, IP, IPv6
+from scapy.all import sendp
+
+class PacketQueue:
+    def __init__(self):
+        self.pkts = []
+        self.lock = threading.Lock()
+        self.ifaces = set()
+
+    def add_iface(self, iface):
+        self.ifaces.add(iface)
+
+    def get(self):
+        self.lock.acquire()
+        if not self.pkts:
+            self.lock.release()
+            return None, None
+        pkt = self.pkts.pop(0)
+        self.lock.release()
+        return pkt
+
+    def add(self, iface, pkt):
+        if iface not in self.ifaces:
+            return
+        self.lock.acquire()
+        self.pkts.append( (iface, pkt) )
+        self.lock.release()
+
+queue = PacketQueue()
+
+def pkt_handler(pkt, iface):
+    if IPv6 in pkt:
+        return
+    queue.add(iface, pkt)
+
+class SnifferThread(threading.Thread):
+    def __init__(self, iface, handler = pkt_handler):
+        threading.Thread.__init__(self)
+        self.iface = iface
+        self.handler = handler
+
+    def run(self):
+        sniff(
+            iface = self.iface,
+            prn = lambda x: self.handler(x, self.iface)
+        )
+
+class PacketDelay:
+    def __init__(self, bsize, bdelay, imin, imax, num_pkts = 100):
+        self.bsize = bsize
+        self.bdelay = bdelay
+        self.imin = imin
+        self.imax = imax
+        self.num_pkts = num_pkts
+        self.current = 1
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        if self.num_pkts <= 0:
+            raise StopIteration
+        self.num_pkts -= 1
+        if self.current == self.bsize:
+            self.current = 1
+            return random.randint(self.imin, self.imax)
+        else:
+            self.current += 1
+            return self.bdelay
+
+
+pkt = Ether()/IP(dst='10.0.0.1', ttl=64)
+
+port_map = {
+    1: "veth3",
+    2: "veth5",
+    3: "veth7"
+}
+
+iface_map = {}
+for p, i in port_map.items():
+    iface_map[i] = p
+
+queue.add_iface("veth3")
+queue.add_iface("veth5")
+
+for p, iface in port_map.items():
+    t = SnifferThread(iface)
+    t.daemon = True
+    t.start()
+
+import socket
+
+send_socket = socket.socket(socket.AF_PACKET, socket.SOCK_RAW,
+                            socket.htons(0x03))
+send_socket.bind((port_map[3], 0))
+
+delays = PacketDelay(10, 5, 25, 100, NUM_PACKETS)
+ports = []
+print "Sending", NUM_PACKETS, "packets ..."
+for d in delays:
+    # sendp is too slow...
+    # sendp(pkt, iface=port_map[3], verbose=0)
+    send_socket.send(str(pkt))
+    time.sleep(d / 1000.)
+time.sleep(1)
+iface, pkt = queue.get()
+while pkt:
+    ports.append(iface_map[iface])
+    iface, pkt = queue.get()
+print ports
diff --git a/SIGCOMM_2015/flowlet_switching/solution.tar.gz b/SIGCOMM_2015/flowlet_switching/solution.tar.gz
new file mode 100644
index 0000000..4ed6ac6
Binary files /dev/null and b/SIGCOMM_2015/flowlet_switching/solution.tar.gz differ
diff --git a/SIGCOMM_2015/flowlet_switching/veth_setup.sh b/SIGCOMM_2015/flowlet_switching/veth_setup.sh
new file mode 100755
index 0000000..4083541
--- /dev/null
+++ b/SIGCOMM_2015/flowlet_switching/veth_setup.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+noOfVeths=18
+if [ $# -eq 1 ]; then 
+    noOfVeths=$1
+fi
+echo "No of Veths is $noOfVeths"
+idx=0
+let "vethpairs=$noOfVeths/2"
+while [ $idx -lt $vethpairs ]
+do 
+    intf0="veth$(($idx*2))"
+    intf1="veth$(($idx*2+1))"
+    idx=$((idx + 1))
+    if ! ip link show $intf0 &> /dev/null; then
+        ip link add name $intf0 type veth peer name $intf1
+        ip link set dev $intf0 up
+        ip link set dev $intf1 up
+        TOE_OPTIONS="rx tx sg tso ufo gso gro lro rxvlan txvlan rxhash"
+        for TOE_OPTION in $TOE_OPTIONS; do
+           /sbin/ethtool --offload $intf0 "$TOE_OPTION" off
+           /sbin/ethtool --offload $intf1 "$TOE_OPTION" off
+        done
+    fi
+    sysctl net.ipv6.conf.$intf0.disable_ipv6=1
+    sysctl net.ipv6.conf.$intf1.disable_ipv6=1
+done