diff --git a/P4D2_2017_Fall/exercises/README.md b/P4D2_2017_Fall/exercises/README.md
index 256d2b7..2cf3de8 100644
--- a/P4D2_2017_Fall/exercises/README.md
+++ b/P4D2_2017_Fall/exercises/README.md
@@ -9,7 +9,7 @@ programming, organized into four modules:
 
 1. Introduction
 * [Basic Forwarding](./basic)
-* [Scrambler](./scrambler)
+* [Basic Tunneling](./basic_tunnel)
 
 2. Monitoring and Debugging
 * [Explicit Congestion Notification](./ecn)
@@ -21,7 +21,6 @@ programming, organized into four modules:
 
 4. Dynamic Behavior
 * [Load Balancing](./load_balance)
-* [HULA](./hula)
 
 ## Obtaining required software
 
diff --git a/P4D2_2017_Fall/exercises/scrambler/Makefile b/P4D2_2017_Fall/exercises/scrambler/Makefile
deleted file mode 100644
index f378756..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/Makefile
+++ /dev/null
@@ -1 +0,0 @@
-include ../../utils/Makefile
diff --git a/P4D2_2017_Fall/exercises/scrambler/README.md b/P4D2_2017_Fall/exercises/scrambler/README.md
deleted file mode 100644
index 63c3562..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/README.md
+++ /dev/null
@@ -1,123 +0,0 @@
-# Implementing basic forwarding with scrambled addresses
-
-## Introduction
-
-In this exercise, you will extend your solution to the basic
-forwarding exercise with a new twist: switches will invert the bits
-representing Ethernet and IPv4 address. Hence, in our triangle
-topology, the packets in the interior of the network will have
-unintelligble addresses.
-
-> **Spoiler alert:** There is a reference solution in the `solution`
-> sub-directory. Feel free to compare your implementation to the
-> reference.
-
-## Step 1: Run the (incomplete) starter code
-
-The directory with this README also contains a skeleton P4 program,
-`scrambler.p4`, which initially drops all packets. Your job (in the
-next step) will be to extend it to properly forward IPv4 packets.
-
-Before that, let's compile the incomplete `scrambler.p4` and bring
-up a switch in Mininet to test its behavior.
-
-1. In your shell, run:
-   ```bash
-   make
-   ```
-   This will:
-   * compile `scrambler.p4`, and
-   * start a Mininet instance with three switches (`s1`, `s2`, `s3`) configured
-     in a triangle, each connected to one host (`h1`, `h2`, `h3`).
-   * The hosts are assigned IPs of `10.0.1.1`, `10.0.2.2`, etc.
-
-2. You should now see a Mininet command prompt. Open two terminals
-for `h1` and `h2`, respectively:
-   ```bash
-   mininet> xterm h1 h2
-   ```
-3. Each host includes a small Python-based messaging client and
-server. In `h2`'s xterm, start the server:
-   ```bash
-   ./receive.py
-   ```
-4. In `h1`'s xterm, send a message from the client:
-   ```bash
-   ./send.py 10.0.2.2 "P4 is cool"
-   ```
-   The message will not be received.
-5. Type `exit` to leave each xterm and the Mininet command line.
-
-The message was not received because each switch is programmed with
-`scrambler.p4`, which drops all packets on arrival. Your job is to
-extend this file.
-
-### A note about the control plane
-
-P4 programs define a packet-processing pipeline, but the rules
-governing packet processing are inserted into the pipeline by the
-control plane. When a rule matches a packet, its action is invoked
-with parameters supplied by the control plane as part of the rule.
-
-In this exercise, the control plane logic has already been
-implemented. As part of bringing up the Mininet instance, the
-`make` script will install packet-processing rules in the tables of
-each switch. These are defined in the `sX-commands.txt` files, where
-`X` corresponds to the switch number.
-
-**Important:** A P4 program also defines the interface between the
-switch pipeline and control plane. The `sX-commands.txt` files
-contain lists of commands for the BMv2 switch API. These commands
-refer to specific tables, keys, and actions by name, and any changes
-in the P4 program that add or rename tables, keys, or actions will
-need to be reflected in these command files.
-
-## Step 2: Extend the basic forwarding solution to flip bits
-
-The `scrambler.p4` file contains a skeleton P4 program in which one of
-the actions has a `TODO` comment. These should guide your
-implementation---replace the `TODO` with logic implementing the
-missing piece.
-
-A complete `scrambler.p4` will add an action `flip()` that inverts the
-bits in the Ethernet and IPv4 headers. 
-
-## Step 3: Run your solution
-
-Follow the instructions from Step 1. This time, your message from
-`h1` should be delivered to `h2`.
-
-### Troubleshooting
-
-There are several issues that might arise when developing your
-solution:
-
-1. `scrambler.p4` fails to compile. In this case, `make` will
-report the error emitted from the compiler and stop.
-
-2. `scrambler.p4` compiles but does not support the control plane
-rules in the `sX-commands.txt` files that `make` tries to install
-using the BMv2 CLI. In this case, `make` will report these errors
-to `stderr`. Use these error messages to fix your `scrambler.p4`
-implementation.
-
-3. `scrambler.p4` compiles, and the control plane rules are installed,
-but the switch does not process packets in the desired way. The
-`build/logs/<switch-name>.log` files contain trace messages describing
-how each switch processes each packet. The output is detailed and can
-help pinpoint logic errors in your implementation.
-
-#### Cleaning up Mininet
-
-In the latter two cases above, `make` may leave a Mininet instance
-running in the background. Use the following command to clean up
-these instances:
-
-```bash
-mn -c
-```
-
-## Next Steps
-
-Congratulations, your implementation works!  Move on to the next
-exercise: implementing [Explicit Congestion Notification](../ecn).
diff --git a/P4D2_2017_Fall/exercises/scrambler/receive.py b/P4D2_2017_Fall/exercises/scrambler/receive.py
deleted file mode 100755
index c93182f..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/receive.py
+++ /dev/null
@@ -1,52 +0,0 @@
-#!/usr/bin/env python
-import sys
-import struct
-import os
-
-from scapy.all import sniff, sendp, hexdump, get_if_list, get_if_hwaddr
-from scapy.all import Packet, IPOption
-from scapy.all import ShortField, IntField, LongField, BitField, FieldListField, FieldLenField
-from scapy.all import IP, UDP, Raw
-from scapy.layers.inet import _IPOption_HDR
-
-def get_if():
-    ifs=get_if_list()
-    iface=None
-    for i in get_if_list():
-        if "eth0" in i:
-            iface=i
-            break;
-    if not iface:
-        print "Cannot find eth0 interface"
-        exit(1)
-    return iface
-
-class IPOption_MRI(IPOption):
-    name = "MRI"
-    option = 31
-    fields_desc = [ _IPOption_HDR,
-                    FieldLenField("length", None, fmt="B",
-                                  length_of="swids",
-                                  adjust=lambda pkt,l:l+4),
-                    ShortField("count", 0),
-                    FieldListField("swids",
-                                   [],
-                                   IntField("", 0),
-                                   length_from=lambda pkt:pkt.count*4) ]
-def handle_pkt(pkt):
-    print "got a packet"
-    pkt.show2()
-#    hexdump(pkt)
-    sys.stdout.flush()
-
-
-def main():
-    ifaces = filter(lambda i: 'eth' in i, os.listdir('/sys/class/net/'))
-    iface = ifaces[0]
-    print "sniffing on %s" % iface
-    sys.stdout.flush()
-    sniff(filter="tcp", iface = iface,
-          prn = lambda x: handle_pkt(x))
-
-if __name__ == '__main__':
-    main()
diff --git a/P4D2_2017_Fall/exercises/scrambler/s1-commands.txt b/P4D2_2017_Fall/exercises/scrambler/s1-commands.txt
deleted file mode 100644
index 0a63bdb..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/s1-commands.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-table_set_default ipv4_lpm drop
-table_add ipv4_lpm ipv4_forward 10.0.2.2/32 => 00:00:00:02:02:00 2
-table_add ipv4_lpm ipv4_forward 10.0.3.3/32 => 00:00:00:03:02:00 3
-table_add ipv4_lpm ipv4_forward 245.255.254.254/32 => ff:ff:ff:ff:fe:fe 1
-table_add ipv4_lpm ipv4_forward 245.255.253.253/32 => 00:00:00:02:02:00 2
-table_add ipv4_lpm ipv4_forward 245.255.252.252/32 => 00:00:00:03:02:00 3
diff --git a/P4D2_2017_Fall/exercises/scrambler/s2-commands.txt b/P4D2_2017_Fall/exercises/scrambler/s2-commands.txt
deleted file mode 100644
index f1797a6..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/s2-commands.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-table_set_default ipv4_lpm drop
-table_add ipv4_lpm ipv4_forward 10.0.1.1/32 => 00:00:00:01:02:00 2
-table_add ipv4_lpm ipv4_forward 10.0.3.3/32 => 00:00:00:03:03:00 3
-table_add ipv4_lpm ipv4_forward 245.255.254.254/32 => 00:00:00:01:02:00 2
-table_add ipv4_lpm ipv4_forward 245.255.253.253/32 => ff:ff:ff:ff:fd:fd 1
-table_add ipv4_lpm ipv4_forward 245.255.252.252/32 => 00:00:00:03:03:00 3
diff --git a/P4D2_2017_Fall/exercises/scrambler/s3-commands.txt b/P4D2_2017_Fall/exercises/scrambler/s3-commands.txt
deleted file mode 100644
index a04f7ba..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/s3-commands.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-table_set_default ipv4_lpm drop
-table_add ipv4_lpm ipv4_forward 10.0.0.1/32 => 00:00:00:01:02:00 2
-table_add ipv4_lpm ipv4_forward 10.0.0.2/32 => 00:00:00:02:03:00 3
-table_add ipv4_lpm ipv4_forward 245.255.254.254/32 => 00:00:00:01:01:00 2
-table_add ipv4_lpm ipv4_forward 245.255.253.253/32 => 00:00:00:02:03:00 3
-table_add ipv4_lpm ipv4_forward 245.255.252.252/32 => ff:ff:ff:ff:fc:fc 1
diff --git a/P4D2_2017_Fall/exercises/scrambler/scrambler.p4 b/P4D2_2017_Fall/exercises/scrambler/scrambler.p4
deleted file mode 100644
index 8d4e115..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/scrambler.p4
+++ /dev/null
@@ -1,180 +0,0 @@
-/* -*- P4_16 -*- */
-#include <core.p4>
-#include <v1model.p4>
-
-const bit<16> TYPE_IPV4 = 0x800;
-
-/*************************************************************************
-*********************** H E A D E R S  ***********************************
-*************************************************************************/
-
-typedef bit<9>  egressSpec_t;
-typedef bit<48> macAddr_t;
-typedef bit<32> ip4Addr_t;
-
-header ethernet_t {
-    macAddr_t dstAddr;
-    macAddr_t srcAddr;
-    bit<16>   etherType;
-}
-
-header ipv4_t {
-    bit<4>    version;
-    bit<4>    ihl;
-    bit<8>    diffserv;
-    bit<16>   totalLen;
-    bit<16>   identification;
-    bit<3>    flags;
-    bit<13>   fragOffset;
-    bit<8>    ttl;
-    bit<8>    protocol;
-    bit<16>   hdrChecksum;
-    ip4Addr_t srcAddr;
-    ip4Addr_t dstAddr;
-}
-
-struct metadata {
-    /* empty */
-}
-
-struct headers {
-    ethernet_t   ethernet;
-    ipv4_t       ipv4;
-}
-
-/*************************************************************************
-*********************** P A R S E R  ***********************************
-*************************************************************************/
-
-parser MyParser(packet_in packet,
-                out headers hdr,
-                inout metadata meta,
-                inout standard_metadata_t standard_metadata) {
-
-    state start {
-        transition parse_ethernet;
-    }
-
-    state parse_ethernet {
-        packet.extract(hdr.ethernet);
-        transition select(hdr.ethernet.etherType) {
-            TYPE_IPV4: parse_ipv4;
-            default: accept;
-        }
-    }
-
-    state parse_ipv4 {
-        packet.extract(hdr.ipv4);
-        transition accept;
-    }
-}
-
-
-/*************************************************************************
-************   C H E C K S U M    V E R I F I C A T I O N   *************
-*************************************************************************/
-
-control MyVerifyChecksum(inout headers hdr, inout metadata meta) {   
-    apply {  }
-}
-
-
-/*************************************************************************
-**************  I N G R E S S   P R O C E S S I N G   *******************
-*************************************************************************/
-
-control MyIngress(inout headers hdr,
-                  inout metadata meta,
-                  inout standard_metadata_t standard_metadata) {
-    action drop() {
-        mark_to_drop();
-    }
-
-    action flip() {
-        /* TODO: add code to flip bits in Ethernet and IPv4 addresses. */	
-    }
-
-    action ipv4_forward(macAddr_t dstAddr, egressSpec_t port) {
-        standard_metadata.egress_spec = port;
-        hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
-        hdr.ethernet.dstAddr = dstAddr;
-        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
-	flip();
-    }
-    
-    table ipv4_lpm {
-        key = {
-            hdr.ipv4.dstAddr: lpm;
-        }
-        actions = {
-            ipv4_forward;
-            drop;
-            NoAction;
-        }
-        size = 1024;
-        default_action = NoAction();
-    }
-    
-    apply {
-        if (hdr.ipv4.isValid()) {
-            ipv4_lpm.apply();
-        }
-    }
-}
-
-/*************************************************************************
-****************  E G R E S S   P R O C E S S I N G   *******************
-*************************************************************************/
-
-control MyEgress(inout headers hdr,
-                 inout metadata meta,
-                 inout standard_metadata_t standard_metadata) {
-    apply {  }
-}
-
-/*************************************************************************
-*************   C H E C K S U M    C O M P U T A T I O N   **************
-*************************************************************************/
-control MyComputeChecksum(inout headers hdr, inout metadata meta) {
-     apply {
-	update_checksum(
-	    hdr.ipv4.isValid(),
-            { hdr.ipv4.version,
-	      hdr.ipv4.ihl,
-              hdr.ipv4.diffserv,
-              hdr.ipv4.totalLen,
-              hdr.ipv4.identification,
-              hdr.ipv4.flags,
-              hdr.ipv4.fragOffset,
-              hdr.ipv4.ttl,
-              hdr.ipv4.protocol,
-              hdr.ipv4.srcAddr,
-              hdr.ipv4.dstAddr },
-            hdr.ipv4.hdrChecksum,
-            HashAlgorithm.csum16);
-    }
-}
-
-/*************************************************************************
-***********************  D E P A R S E R  *******************************
-*************************************************************************/
-
-control MyDeparser(packet_out packet, in headers hdr) {
-    apply {
-        packet.emit(hdr.ethernet);
-        packet.emit(hdr.ipv4);
-    }
-}
-
-/*************************************************************************
-***********************  S W I T C H  *******************************
-*************************************************************************/
-
-V1Switch(
-MyParser(),
-MyVerifyChecksum(),
-MyIngress(),
-MyEgress(),
-MyComputeChecksum(),
-MyDeparser()
-) main;
diff --git a/P4D2_2017_Fall/exercises/scrambler/send.py b/P4D2_2017_Fall/exercises/scrambler/send.py
deleted file mode 100755
index 00496d9..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/send.py
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/env python
-import argparse
-import sys
-import socket
-import random
-import struct
-
-from scapy.all import sendp, send, get_if_list, get_if_hwaddr
-from scapy.all import Packet
-from scapy.all import Ether, IP, UDP, TCP
-
-def get_if():
-    ifs=get_if_list()
-    iface=None # "h1-eth0"
-    for i in get_if_list():
-        if "eth0" in i:
-            iface=i
-            break;
-    if not iface:
-        print "Cannot find eth0 interface"
-        exit(1)
-    return iface
-
-def main():
-
-    if len(sys.argv)<3:
-        print 'pass 2 arguments: <destination> "<message>"'
-        exit(1)
-
-    addr = socket.gethostbyname(sys.argv[1])
-    iface = get_if()
-
-    print "sending on interface %s to %s" % (iface, str(addr))
-    pkt =  Ether(src=get_if_hwaddr(iface), dst='ff:ff:ff:ff:ff:ff')
-    pkt = pkt /IP(dst=addr) / TCP(dport=1234, sport=random.randint(49152,65535)) / sys.argv[2]
-    pkt.show2()
-    sendp(pkt, iface=iface, verbose=False)
-
-
-if __name__ == '__main__':
-    main()
diff --git a/P4D2_2017_Fall/exercises/scrambler/solution/scrambler.p4 b/P4D2_2017_Fall/exercises/scrambler/solution/scrambler.p4
deleted file mode 100644
index e508af6..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/solution/scrambler.p4
+++ /dev/null
@@ -1,191 +0,0 @@
-/* -*- P4_16 -*- */
-#include <core.p4>
-#include <v1model.p4>
-
-const bit<16> TYPE_IPV4 = 0x800;
-
-/*************************************************************************
-*********************** H E A D E R S  ***********************************
-*************************************************************************/
-
-typedef bit<9>  egressSpec_t;
-typedef bit<48> macAddr_t;
-typedef bit<32> ip4Addr_t;
-
-header ethernet_t {
-    macAddr_t dstAddr;
-    macAddr_t srcAddr;
-    bit<16>   etherType;
-}
-
-header ipv4_t {
-    bit<4>    version;
-    bit<4>    ihl;
-    bit<8>    diffserv;
-    bit<16>   totalLen;
-    bit<16>   identification;
-    bit<3>    flags;
-    bit<13>   fragOffset;
-    bit<8>    ttl;
-    bit<8>    protocol;
-    bit<16>   hdrChecksum;
-    ip4Addr_t srcAddr;
-    ip4Addr_t dstAddr;
-}
-
-struct metadata {
-    /* empty */
-}
-
-struct headers {
-    ethernet_t   ethernet;
-    ipv4_t       ipv4;
-}
-
-/*************************************************************************
-*********************** P A R S E R  ***********************************
-*************************************************************************/
-
-parser MyParser(packet_in packet,
-                out headers hdr,
-                inout metadata meta,
-                inout standard_metadata_t standard_metadata) {
-
-    state start {
-        transition parse_ethernet;
-    }
-
-    state parse_ethernet {
-        packet.extract(hdr.ethernet);
-        transition select(hdr.ethernet.etherType) {
-            TYPE_IPV4: parse_ipv4;
-            default: accept;
-        }
-    }
-
-    state parse_ipv4 {
-        packet.extract(hdr.ipv4);
-        transition accept;
-    }
-}
-
-
-/*************************************************************************
-************   C H E C K S U M    V E R I F I C A T I O N   *************
-*************************************************************************/
-
-control MyVerifyChecksum(inout headers hdr, inout metadata meta) {   
-    apply {  }
-}
-
-
-/*************************************************************************
-**************  I N G R E S S   P R O C E S S I N G   *******************
-*************************************************************************/
-
-control MyIngress(inout headers hdr,
-                  inout metadata meta,
-                  inout standard_metadata_t standard_metadata) {
-    action drop() {
-        mark_to_drop();
-    }
-
-    action flip_ethernet() {
-      hdr.ethernet.srcAddr = ~hdr.ethernet.srcAddr;
-      hdr.ethernet.dstAddr = ~hdr.ethernet.dstAddr;
-    }
-    action flip_ipv4() {
-      hdr.ipv4.srcAddr = ~hdr.ipv4.srcAddr;
-      hdr.ipv4.dstAddr = ~hdr.ipv4.dstAddr;
-    }
-
-    action flip() {
-      flip_ethernet();
-      flip_ipv4();
-    }
-
-    action ipv4_forward(macAddr_t dstAddr, egressSpec_t port) {
-        standard_metadata.egress_spec = port;
-        hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
-        hdr.ethernet.dstAddr = dstAddr;
-        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
-	flip();
-    }
-    
-    table ipv4_lpm {
-        key = {
-            hdr.ipv4.dstAddr: lpm;
-        }
-        actions = {
-            ipv4_forward;
-            drop;
-            NoAction;
-        }
-        size = 1024;
-        default_action = NoAction();
-    }
-    
-    apply {
-        if (hdr.ipv4.isValid()) {
-            ipv4_lpm.apply();
-        }
-    }
-}
-
-/*************************************************************************
-****************  E G R E S S   P R O C E S S I N G   *******************
-*************************************************************************/
-
-control MyEgress(inout headers hdr,
-                 inout metadata meta,
-                 inout standard_metadata_t standard_metadata) {
-    apply {  }
-}
-
-/*************************************************************************
-*************   C H E C K S U M    C O M P U T A T I O N   **************
-*************************************************************************/
-
-control MyComputeChecksum(inout headers hdr, inout metadata meta) {
-     apply {
-	update_checksum(
-	    hdr.ipv4.isValid(),
-            { hdr.ipv4.version,
-	      hdr.ipv4.ihl,
-              hdr.ipv4.diffserv,
-              hdr.ipv4.totalLen,
-              hdr.ipv4.identification,
-              hdr.ipv4.flags,
-              hdr.ipv4.fragOffset,
-              hdr.ipv4.ttl,
-              hdr.ipv4.protocol,
-              hdr.ipv4.srcAddr,
-              hdr.ipv4.dstAddr },
-            hdr.ipv4.hdrChecksum,
-            HashAlgorithm.csum16);
-    }
-}
-
-/*************************************************************************
-***********************  D E P A R S E R  *******************************
-*************************************************************************/
-
-control MyDeparser(packet_out packet, in headers hdr) {
-    apply {
-        packet.emit(hdr.ethernet);
-        packet.emit(hdr.ipv4);
-    }
-}
-
-/*************************************************************************
-***********************  S W I T C H  *******************************
-*************************************************************************/
-
-V1Switch(
-MyParser(),
-MyVerifyChecksum(),
-MyIngress(),
-MyEgress(),
-MyComputeChecksum(),
-MyDeparser()
-) main;
diff --git a/P4D2_2017_Fall/exercises/scrambler/topology.json b/P4D2_2017_Fall/exercises/scrambler/topology.json
deleted file mode 100644
index e33477c..0000000
--- a/P4D2_2017_Fall/exercises/scrambler/topology.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-    "hosts": [
-        "h1",
-        "h2",
-        "h3"
-    ],
-    "switches": {
-        "s1": { "cli_input" : "s1-commands.txt" },
-        "s2": { "cli_input" : "s2-commands.txt" },
-        "s3": { "cli_input" : "s3-commands.txt" }
-    },
-    "links": [
-        ["h1", "s1"], ["s1", "s2"], ["s1", "s3"], 
-        ["s3", "s2"], ["s2", "h2"], ["s3", "h3"]
-    ]
-}