# IPv6 packet length · example 3

Subject: Computer Networks

Exam: TEE

Reader: https://deep-learning-study-room.vercel.app/cn/#tee/practice/ipv6/length-3

Canonical: https://deep-learning-study-room.vercel.app/read/cn/tee/practice/ipv6--length-3/

Optional extension · no matching calculation in the two supplied papers

**Optional worked extension.** This calculation format was not found in the supplied December 2025 final or February 2026 re-exam. The numbers and practice marks are authored. Study the core concept and actual-paper questions first; this is extra explanation, not a TEE prediction.

### Practice question. An IPv6 packet has a 40-byte base header, 40 bytes of extension headers and 500 bytes of upper-layer content. Find its Payload Length field value and total packet length. [3 practice marks]

#### Answer

## Given

Base=40 bytes; extensions=40 bytes; upper-layer content=500 bytes. Ordinary non-jumbo packet.

## To find

Payload Length and total bytes.

## Formula and why



$$
P=E+D,\qquad T=40+P
$$



Payload begins immediately after the IPv6 base header. Extensions are part of that payload.

## Step-by-step solution

#### Step 1. Calculate payload

P=40+500=540 bytes.

#### Step 2. Add the base header

T=40+540=580 bytes.

#### Step 3. Identify the stored field

The Payload Length field stores 540, not 580.

**Final answer:** Payload Length=540; total=580 bytes.

#### What this result means

Do not count the base header twice or leave extension-header bytes out of the payload length.