<p><i>For U.S. Edition. Last revision: 20 June 2014</i></p>

<p>We welcome mail noting corrections, clarifications and other improvements, and will incorporate them in the next revision. Meanwhile, the known errata are listed below. Italics denote the reading of text after correction. Not listed for brevity are spelling, grammar and punctuation mistakes that do not affect the meaning of text.</p>

<p>Please send further errata to David Wetherall (<i>dj</i><i>w@uw</i><i>.edu</i>).</p>

<h1>Chapter 1</h1>

<h1>Chapter 2</h1>

<p>Page 130: Correction to the figure references. FSK is shown in <i>Fig. 2-22(c)</i> and PSK is shown in <i>Fig. 2-22(d)</i></p>

<p>Page 137: Correction to Fig. 2-28(d). The top "S1 dot C" line should have all +1s so that it reads <i>"[1+1+1+1+1+1+1+1]/8=1".</i>
</p>

<p>Page 158: Correction to the last sentence of the second paragraph. There are 86, not 87, payload columns of user data. The sentence should read <i>"The user data rate excludes all three kinds of overhead and counts only the 86 payload columns".</i>
</p>

<p>Page 188: Clarification of Problem 2.16 to explicitly note that NRZI encoding is used with 4B/5B. <i>"2.16 Prove that in 4B/5B mapped data with the NRZI encoding, a signal transition will occur at least every four bit times."</i>
</p>

<h1>Chapter 3</h1>

<p>Page 234: Correction in second to last paragraph. The wrong figure is referenced and described. It should read <i>"In Fig. 3-18(a) we see the go-back-n case in which the receiver's window is 1."</i>
</p>

<h1>Chapter 4</h1>

<p>Page 336: Correction in paragraph after the bullet list. The wrong port number is given in the example. It should read <i>"The frame will arrive at B2 on port 2 ...".</i>
</p>

<p>Page 352: Rewording of the start of Problem 16. <i>"Two CSMA/CD stations are each trying to transmit a frame. They both contend for the channel, using the binary exponential backoff algorithm after a collision."</i>
</p>

<h1>Chapter 5</h1>

<p>Page 410: Correction in fourth paragraph. "Mbit" should be "Kbit" so that the text in parentheses reads <i>"e.g., 200 Kbit is 20 packets of 1250 bytes".</i>
</p>

<p>Page 443: Correction to the prefix address. The prefix with "24 bits in the network portion" should be <i>128.208.2.0/24</i>.</p>

<p>Page 469: Correction to IP address in 5.6.4 (ARP). By convention, the default gateway is the lowest address on the network <i>(198.32.65.1)</i>. Similarly, 198.31.65.1 should be <i>198.32.65.1</i> later in the same paragraph.</p>

<p>Page 476: Correction to Fig. 5-64 (b). Change the "LAN 1" label on the right side (connected to R3, R4, and R5) to be "LAN 3" so that it matches part (a) of the figure.</p>

<p>Page 492: Correction in Problem 5.32. The IP address range is incorrect. It should read <i>"IP addresses from 29.18.0.0 to 29.18.127.255 ..."</i>.
</p>

<p>Page 545: Correction to sentence. When a packet arrives at the NAT box from the ISP, the <i>destination port</i> in the TCP header is extracted and used as an index into the NAT Box's mapping table.</p>

<h1>Chapter 6</h1>

<h1>Chapter 7</h1>

<p>Page 648: Correction to Fig. 7-18. Reverse the direction of the arrows labeled "HTTP Request" and "HTTP Response"; they are backwards.</p>

<p>Page 656: Correction in the third paragraph. Sentence should concern multiple requests and read <i>"To tackle the problem of serving more than a single ..."</i></p>

<h1>Chapter 8</h1>

<h1>Chapter 9</h1>