Lectures notes for 2010 - KTH
Lectures notes for 2010 - KTH Lectures notes for 2010 - KTH
Length Fields • Header Length (4 bits) • Size of IPv4 header including IP options • Expressed in number of 32-bit words (4-byte words) • Minimum is 5 words (i.e., 20 bytes) • Maximum is 15 words (i.e., 60 bytes) – limited size ⇒ limited use • Total Length (16 bits) • Total length of datagram including header • If datagram is fragmented: length of this fragment • Expressed in bytes • Hosts only have to accept packets up to 576 bytes in size • Maximum: 65,535 bytes – Most modern systems accept slightly larger than 8,196 + header bytes (to provide efficient file service for 8 Kbyte blocks) – Note: Some systems only accept this much! Maguire Length Fields 3: 5 of 33 maguire@kth.se 2010.03.21 Internetworking/Internetteknik
MTU½≡Maximum Transmission Unit MTU is a characteristic of the link layer Typical MTUS MTU Network 65535 Official maximum MTU 17914 16Mbps IBM Token Ring 8166 IEEE 802.4 4464 IEEE 802.5 (4Mbps max) 4352 FDDI (Revised) 2048 Wideband Network 2002 IEEE 802.5 (4Mb recommended) 1536 Experimental Ethernet Nets 1500 Ethernet Networks 1500 Point-to-Point (default) 1492 IEEE 802.3 1006 SLIP simply a logical limit for interactive response 1006 ARPANET 576 X.25 Networks ⇐ we will see this number again! 544 DEC IP Portal 512 NETBIOS 508 IEEE 802/Source-Route Bridge 296 Point-to-Point (low delay) 68 Official minimum MTU Maguire MTU½≡Maximum Transmission Unit 3: 6 of 33 maguire@kth.se 2010.03.21 Internetworking/Internetteknik
- Page 153 and 154: Forwarding • Next-Hop method - ro
- Page 155 and 156: Forwarding module A simplified view
- Page 157 and 158: Fast forwarding Mikael Degermark, A
- Page 159 and 160: where ddd is some numeric value. Ro
- Page 161 and 162: Host routing A host either: • kno
- Page 163 and 164: Combining layers Many devices now c
- Page 165 and 166: What to do with a new computer? We
- Page 167 and 168: ARP ≡ Address Resolution Protocol
- Page 169 and 170: Address Resolution Cache Since you
- Page 171 and 172: ARP example 2 B FTPd C resolver (1)
- Page 173 and 174: Gratuitous ARP Host sends a request
- Page 175 and 176: ARP - as seen with ethereal Time So
- Page 177 and 178: RARP: Reverse Address Resolution Pr
- Page 179 and 180: RARP server Someone has to know the
- Page 181 and 182: Novel IPX/SPX Addresses Another app
- Page 183 and 184: tcpdump Under HP-UX 11.0 # ./tcpdum
- Page 185 and 186: Tools Used: tcpdump Program tcpdump
- Page 187 and 188: Maguire Wireshark (formerly Etherea
- Page 189 and 190: Tools Used: sock Program • A simp
- Page 191 and 192: #include #include #include #incl
- Page 193 and 194: Wireshark’s IO Graph functionalit
- Page 195 and 196: Interarrival delay and variance Fig
- Page 197 and 198: Summary This lecture we have discus
- Page 199 and 200: [10] Gianluca Insolvibile, “The L
- Page 201 and 202: • IP • ICMP • Useful Diagnost
- Page 203: checksum, and options fields. Magui
- Page 207 and 208: Fields relevant to Fragmentation
- Page 209 and 210: Serial line throughput At 9,000 bit
- Page 211 and 212: 7 {ECN Capable Transport (ECT) and
- Page 213 and 214: Precedence Precedence values are de
- Page 215 and 216: Precendence and telephony systems S
- Page 217 and 218: TTL field Time To Live (TTL) (8 bit
- Page 219 and 220: IPv4 Options • IPv4 options were
- Page 221 and 222: Categories of IP Options • Single
- Page 223 and 224: ICMP Port Unreachable Error Example
- Page 225 and 226: PING: Packet InterNet Groper or son
- Page 227 and 228: On a HP-UX 11.0 machine: ping -ov w
- Page 229 and 230: Useful Tool: Traceroute Programs De
- Page 231 and 232: This lecture we have discussed: •
- Page 233 and 234: IK1550 Internetworking/Internettekn
- Page 235 and 236: Transport layer protocols The trans
- Page 237 and 238: User Datagram Protocol (UDP) • Da
- Page 239 and 240: UDP Checksum and Pseudo-Header •
- Page 241 and 242: Port numbers in three groups Range
- Page 243 and 244: Fragmentation Required If datagram
- Page 245 and 246: • on a BSDI system: • each of t
- Page 247 and 248: With an even larger UDP packet I re
- Page 249 and 250: Datagram truncation What if the app
- Page 251 and 252: Learning about Socket programming F
- Page 253 and 254: UDP server design Stevens, Vol, 1,
Length Fields<br />
• Header Length (4 bits)<br />
• Size of IPv4 header including IP options<br />
• Expressed in number of 32-bit words (4-byte words)<br />
• Minimum is 5 words (i.e., 20 bytes)<br />
• Maximum is 15 words (i.e., 60 bytes)<br />
– limited size ⇒ limited use<br />
• Total Length (16 bits)<br />
• Total length of datagram including header<br />
• If datagram is fragmented: length of this fragment<br />
• Expressed in bytes<br />
• Hosts only have to accept packets up to 576 bytes in size<br />
• Maximum: 65,535 bytes<br />
– Most modern systems accept slightly larger than 8,196 + header bytes<br />
(to provide efficient file service <strong>for</strong> 8 Kbyte blocks)<br />
– Note: Some systems only accept this much!<br />
Maguire Length Fields 3: 5 of 33<br />
maguire@kth.se <strong>2010</strong>.03.21 Internetworking/Internetteknik
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