Hyperconverged Infrastructure Internet as a global system Seamless - - PowerPoint PPT Presentation
Hyperconverged Infrastructure Internet as a global system Seamless integration of compute, network and storage Performance vs. Layering New technologies New Applications CSci8211: Introduction 1 Subjects
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First class, express mail, bulk rate, certified, registered, …
You may get a busy dial tone
Once connected, consistently good quality, unless using cell phones
Reliable connection-oriented or unreliably connectionless services!
You never get a busy dial tone, but things can be very slow!
You can’t ask for express delivery (not at the moment at least!)
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applicatio n
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routing table
Routing protocols
IP protocol
ICMP protocol
Transport layer: TCP, UDP Data Link layer (Ethernet, WiFi, PPP, …) Physical Layer (SONET, …)
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ver length 32 bits
16-bit identifier Internet checksum time to live 32 bit source IP address IP protocol version number header length (bytes) max number remaining hops (decremented at each router) for fragmentation/ reassembly total datagram length (bytes) upper layer protocol to deliver payload to head. len type of service “type” of data flgs fragment
upper layer 32 bit destination IP address Options (if any) E.g. timestamp, record route taken, specify list of routers to visit.
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– 32 bits – two-parts: network prefix and host parts – E.g., 128.101.33.101 network prefix: 128.101.0.0/16
– Each host/router has IP forwarding table
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LANs International lines ISP ISP company university national network regional network NAP Internic
services company
access via modem
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Figure 4.5.2-new2: BGP use for inter-domain routing AS2
(OSPF intra-AS routing)
AS1
(RIP intra-AS routing)
BGP AS3
(OSPF intra-AS routing)
BGP R1 R2 R3 R4 R5
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application transport network link physical P1 application transport network link physical application transport network link physical P2 P3 P4 P1
= process = API (“socket”)
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– lost – delivered out of order to app
– no handshaking between UDP sender, receiver – each UDP segment handled independently of others
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source port # dest port # 32 bits
length checksum Length, in bytes of UDP segment, including header
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– bi-directional data flow in same connection – MSS: maximum segment size
– handshaking (exchange of control msgs) init’s sender, receiver state before data exchange
– sender will not overwhelm receiver
–
– no “message boundaries”
– TCP congestion and flow control set window size
socket door TCP send buffer TCP receive buffer socket door
segment
application writes data application reads data
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32 bits
rcvr window size ptr urgent data checksum
F S R P A U
head len not used
URG: urgent data (generally not used) ACK: ACK # valid RST, SYN, FIN: connection estab (setup, teardown commands) # bytes rcvr willing to accept counting by bytes
(not segments!) Internet checksum (as in UDP) PSH: push data now (generally not used)
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– Hierarchical name space divided into zones – Translation of names to/from IP addresses – Distributed over a collection of DNS servers
– Extract server name (e.g., from the URL) – Invoke system call to trigger DNS resolver code – E.g., gethostbyname() on “www.foo.com”
– Extract client IP address from socket – Optionally invoke system call to translate into name – E.g., gethostbyaddr() on “12.34.158.5”
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in- addr
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Application
DNS resolver
Local DNS server 1 10
DNS cache
DNS query 2 DNS response 9
3 4
5 6
7 8
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– Syntax and semantics of the messages between hosts – Tailored to the specific application (e.g., Web, e-mail) – Messages transferred over transport connection (e.g., TCP)
– Telnet, FTP, SMTP, NNTP, HTTP, …
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HTTP TCP IP
Ethernet interface
HTTP TCP IP
Ethernet interface
IP IP
Ethernet interface Ethernet interface SONET interface SONET interface
host host router router
HTTP message TCP segment IP packet IP packet IP packet
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– Everyone shares same implementation: no need to redo it (reduces bugs, less work, etc…) – Knowing everyone is doing the same thing, can help
– TCP is “outside” the network; compliance is “optional” – We do this for fairness (but realize that people could cheat)
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