emmaleee789/ece438_mp2_tcp-over-udp-implementation

TCP-over-UDP-implementation

UIUC ECE438 MP2

How to use

Commands:

./sender receiver_hostname receiver_port filename_to_xfer bytes_to_xfer

./receiver UDP_port filename_to_write

How to limit network performance:

You can use the same basic test environment described above. However, the network performance will be ridiculously good (same goes for testing on localhost), so you’ll need to limit it.

If your network interface inside the VM is eth0, then run (from inside the VM) the following command:

sudo tc qdisc del dev eth0 root 2>/dev/null

to delete existing tc rules. Then use,

sudo tc qdisc add dev eth0 root handle 1:0 netem delay 20ms loss 5%

followed by

sudo tc qdisc add dev eth0 parent 1:1 handle 10: tbf rate 20Mbit burst 10mb latency 1ms

will give you a 20Mbit, 20ms RTT link where every packet sent has a 5% chance to get dropped. Simply omit the loss n% part to get a channel without artificial drops.

(You can run these commands just on the sender; running them on the receiver as well won’t make much of a difference, although you’ll get a 20ms RTT if you don’t adjust the delay to account for the fact that it gets applied twice.)

Components of TCP

• RTT Estimation & Timeout
• Reliable Data Transfer
• Congestion Control
• Connection Management

RTT Estimation & Timeout:

based on RFC6289

Reliable Data Transfer:

TCP Segment Structure

Congestion Control:

CWND

Connection Management:

TCP 3-way handshake & 4-way handshake