Lectures notes for 2010 - KTH

Lectures notes for 2010 - KTH Lectures notes for 2010 - KTH

20.01.2014 Views

IP header UDP header 20 bytes 8 bytes IP datagram UDP datagram TFTP message opcode 1=RRQ 2=WRQ Filename opcode block 3=data number data 2 bytes 2 bytes 0-512 bytes opcode block 4=ACK number 0 Mode 0 opcode block 5=error number error message 0 Figure 2: TFTP messages (see Stevens, Vol. 1, figure 15.1, pg. 210) Filename and Mode (“netascii” or “octet”) are both N bytes sequences terminated by a null byte. Widely used for bootstrapping diskless systems (such as X terminals) and for dumping the configuration of routers (this is where the write request is used) Maguire Trivial File Transfer Procotol (TFTP) 4: 42 of 74 maguire@kth.se 2010.03.21 Internetworking/Internetteknik

Mapping names to IP addresses Host name: string “ccslab1.kth.se” Name Resolution: DNS IP address 32 bit 130.237.15.254 ARP RARP HW address: 48 bit Ethernet MAC address “08:00:2B:00:EE:0B” Figure 3: mapping between host names and IP address(es) Addr. Resolution Maguire Mapping names to IP addresses 4: 43 of 74 maguire@kth.se 2010.03.21 Internetworking/Internetteknik

Mapping names to IP addresses<br />

Host name: string “ccslab1.kth.se”<br />

Name Resolution: DNS<br />

IP address 32 bit 130.237.15.254<br />

ARP<br />

RARP<br />

HW address: 48 bit Ethernet MAC address<br />

“08:00:2B:00:EE:0B”<br />

Figure 3: mapping between host names and IP address(es)<br />

Addr. Resolution<br />

Maguire Mapping names to IP addresses 4: 43 of 74<br />

maguire@kth.se <strong>2010</strong>.03.21 Internetworking/Internetteknik

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