CN ARQ Protocol

Question

True / False?

Selective repeat ARQ requires more number of bits in sequence number as compared to Go Back n ARQ.

Comments

Bits where? It's not much clear to me. Do you mean bits in `window size` field in TCP segment?

---

Updated question

---

i guess the number of bits required for sequencing the packets depend on the no of packets that can be present in the channel simultaneously . Since at any times these many packets are in transmission ( in either directions) , the requirement is to sequence them uniquely.

---

True because in gbn sender window size is n and receiver window size is 1

Then sn = n+1

But in sr both sender and receiver have window size n

Then sn= 2n

Answer 1

yes, that is correct. in GBN & SR protocol to have the same sender window size, in GBN if we need n bits then in SR protocol we will need n+1 bits. With n sequence bits in GBN sender window size can be up to $2^n-1$, while in SR protocol sender window size can only be up to 2^(n-1)

Comments

1. Question does not says we need to maintain same window size. So do we need to assume that?

2. If i say you assume the first point,If i take n=1,then both have same size.So how can we say it is always true?

---

If n = 1, it would become Stop and Wait. For GBN and SR, n > 1.

Answer 2

it should be true if they mention to maintain same window size.but here not mentioned so its not true