tcp connection management reliability and congestion control short notes

Final Revision Checklist

Final Revision Checklist [ ] Handshake: SYN \to SYN-ACK \to ACK. Synchronizes ISNs. [ ] Consumption: SYN = 1, FIN = 1, Data = N bytes, ACK = 0. [ ] Ack Rule: Ack Number = Received Seq + Consumed. [ ] States: Client: SYN_SENT \to ESTABLISHED. Server: LISTEN \to SYN_RCVD \to ESTABLISHED. [ ] Termination: 4-way handshake. FIN \to ACK \to FIN \to ACK. Allows half-close. [ ] Crash Trap: Server loses TCB. Replies with RST to unknown segments.

Summary: Sequence Number Wraparound

Summary: Sequence Number Wraparound Tracking SEQ = first byte offset ACK = next expected byte offset Wraparound Finite sequence numbers rolling over to 0 and colliding with old packets. The Master Formula 2^{n} > Bandwidth \times T T = MSL (Standard wraparound) T = 2 \times MSL (Connection reuse safety) Final Checklist 1. Did I match bits and bytes correctly? (Divide bps by 8 for Bytes/sec). 2. Did I use the correct time window (MSL vs 2 \times MSL)? 3. Is the inequality strictly greater than (>)? 4. Did I ignore the RTT distractor?

Summary: Congestion Window Evolution

Summary: Congestion Window Evolution Effective Window min (r w n d, c w n d) Slow Start c w n d doubles every RTT. Ends when c w n d \geq ss t h r es h . Loss Recovery Rules (Let W be c w n d before loss) Timeout: ss t h r es h = W /2, c w n d = 1 MSS . 3 Dup ACKs: ss t h r es h = W /2, c w n d = ss t h r es h . Final Checklist 1. Did I convert KB to MSS correctly? 2. Did I check c w n d \geq ss t h r es h to determine the phase? 3. Did I apply the correct loss recovery rule? 4. Did I sum the RTTs to find the exact segment transmission time?

TCP Connection Management, Reliability and Congestion Control Short Notes for GATE CS

TCP Connection Management, Reliability and Congestion Control short notes for GATE CS: 3 study cards covering concepts, formulas, shortcuts and exam traps, plus solved practice questions.

Final Revision Checklist

[ ] Handshake: SYN

\to

SYN-ACK

\to

ACK. Synchronizes ISNs.

[ ] Consumption: SYN = 1, FIN = 1, Data =

N

bytes, ACK = 0.

[ ] Ack Rule: Ack Number = Received Seq + Consumed.

[ ] States: Client: SYN_SENT

\to

ESTABLISHED. Server: LISTEN

\to

SYN_RCVD

\to

ESTABLISHED.

[ ] Termination: 4-way handshake. FIN

\to

ACK

\to

FIN

\to

ACK. Allows half-close.

[ ] Crash Trap: Server loses TCB. Replies with RST to unknown segments.

Summary: Sequence Number Wraparound

Tracking

SEQ = first byte offset
ACK = next expected byte offset

Wraparound

Finite sequence numbers rolling over to

0

and colliding with old packets.

The Master Formula

2^{n} > Bandwidth \times T

T = MSL

(Standard wraparound)

T = 2 \times MSL

(Connection reuse safety)

Final Checklist

1. Did I match bits and bytes correctly? (Divide bps by 8 for Bytes/sec).

2. Did I use the correct time window (MSL vs

2 \times MSL

3. Is the inequality strictly greater than (

>

4. Did I ignore the RTT distractor?

Summary: Congestion Window Evolution

Effective Window

min (r w n d, c w n d)

Slow Start

c w n d

doubles every RTT. Ends when

c w n d \geq ss t h r es h

Loss Recovery Rules (Let

W

c w n d

before loss)

Timeout:

ss t h r es h = W /2

c w n d = 1 MSS

3 Dup ACKs:

ss t h r es h = W /2

c w n d = ss t h r es h

Final Checklist

1. Did I convert KB to MSS correctly?

2. Did I check

c w n d \geq ss t h r es h

to determine the phase?

3. Did I apply the correct loss recovery rule?

4. Did I sum the RTTs to find the exact segment transmission time?