1. Router Implementation Project-2
Discussion November 17, 2014
CSE 123-Fall 2014

2. Topology The skeleton and dependencies of the project have been
setup in a VM for your
convenience.
VM has the network
topology and the allows
your router implementation
to talk with the network topology.

3. Overview What your routing logic needs to do
Route Ethernet frames between the Internet (the myth cluster) and the HTTP servers
Handle ARP request and replies
Handle traceroutes
Generate TTL Exceeds Message
Handle TCP/UDP packets sent to one of the routers' interfaces
Generate ICMP Port Unreachable
Respond to ICMP echo requests
Maintain an ARP cache
See webpage for full requirements

4. Getting Started
Load the virtual machine disk image into your favourite VMM. Eg: VMWare Player, VirtualBox, VMWare fusion etc.
Username/Password is mininet/mininet.
Start Mininet and POX. Two steps to get the infrastructure up and running
./cse123-p2/run_mininet.sh
○ ./cse123-p2/run_pox.sh
Build and execute router
make clean
○ make
○ ./sr
Check packet flow with wireshark
Expected output

5. ARP Flow Chart Receive Raw Ethernet Frame It's an IP packet
It's an ARP packet
Cache it, go
through my
request queue
and send
outstanding
packets
Construct an ARP
reply and send it
back
Reply to me
Request to me

6. IP Flow Chart

7. Coding Advice sr_protocol.h ip header def sr_ethernet_hdr def
hdr_icmp_t def
arp header def
Protocol Resolution definitions
Sr_if.c
sr_get_interfaces
sr_add_interface
sr_set_ether_addr (set to the last interface in the interface list)
sr_set_ether_ip
Print funcs for debugging

8. Questions?