Transcript Network Standards and Protocols - Instituto Tecnológico de Morelia

Standards and Network
Protocols
M.C. Juan Carlos Olivares Rojas
Department of Computer and System
Instituto Tecnológico de Morelia
[email protected]
19.72388 lat, -101.1848 long
Disclaimer
Some material in this presentation has been
obtained from various sources, each of which
has intellectual property, so in this presentation
will only have some rights reserved.
These slides are free, so you can add, modify,
and delete slides (including this one) and slide
content to suit your needs. They obviously
represent a lot of work on my part. In return for
use, I only ask the following: if you use these
slides (e.g., in a class) in substantially unaltered
form, that you mention their source.
Outline
Standards of IEEE LAN Conection.
802 Project Connection.
802.1 Connection between Networks.
802.2 Logical Link Control (LLC).
802.3 Ethernet.
802.4 Token Bus.
802.5 Token Ring.
802.6 FDDI.
802.11 Wireless LAN.
Outline
Protocol Architectures
TCP/IP
NetBEUI/NetBIOS
IPX/SPX.
Emergent Protocols
Similarities and differences between OSI and
TCP/IP models.
Objectives of the Session
• The students will know the basis of
intenrnational computer networks standards.
• The students will know and apply the LAN
concepts.
Standards of IEEE LAN
Conection
The standards only indicate how computer
networks must be works guarantee
interoperability between another Equipments.
The main functions in the 802.x standards are
the framming and Medium Access Control.
IEEE 802.x Technologies
• The group of standards 802.x is concern about
the implementation and use of Local Area
Network (e.g. TokenRing, Ethernet) and Wide
Area Network (e.g. FDDI, WiMax).
• These standars are focused in DataLink Layer.
The transmission medium can be wired o
wireless.
• Some standards are focused in define services
in DataLink Layer such quality of service,
security, among others.
802.1 Connection between
Networks
DataLink Services
•
•
•
•
•
Provide services to the Network Layer
Send and receive data in a frame format
Processing and error correction
DataFlow Control
Medium Access Control ***
Where is the link layer implemented?
• in each and every host
• link layer implemented in
“adaptor” (aka network
interface card NIC)
– Ethernet card, PCMCI card,
802.11 card
– implements link, physical
layer
• attaches
into
host’s
system buses
• combination of hardware,
software, firmware
host schematic
application
transport
network
link
cpu
memory
controller
link
physical
host
bus
(e.g., PCI)
physical
transmission
network adapter
card
MAC Addressing
• MAC (or LAN or physical or Ethernet) address:
– function: get frame from one interface to another
physically-connected interface (same network)
– 48 bit MAC address (for most LANs)
• burned in NIC ROM, also sometimes software settable
LAN Addresses
Each adapter on LAN has unique LAN address
1A-2F-BB-76-09-AD
71-65-F7-2B-08-53
LAN
(wired or
wireless)
Broadcast address =
FF-FF-FF-FF-FF-FF
= adapter
58-23-D7-FA-20-B0
0C-C4-11-6F-E3-98
802.2 Logical Link Control (LLC)
The Logical Link Control (LLC) data
communication protocol layer is the upper
sublayer of the Data Link Layer specified in
the seven-layer OSI model (layer 2).
It provides multiplexing and flow control
mechanisms that make it possible for several
network protocols (IP, IPX) to coexist within a
multipoint network and to be transported over
the same network media.
802.2 Logical Link Control (LLC)
The LLC sub-layer acts as an interface
between the Media Access Control (MAC)
sublayer and the network layer. It is the same
for the various physical media (such as
Ethernet, token ring, and WLAN).
Medium Access Control
• There are a lot of technices for sharing the
transmision medium. The more used in
computer networks are:
•
•
•
•
•
ALOHA
CSMA
Protocols without colision
Wireless Protocol
Other Multiplexation
ALOHA
The frames are transmitting in arbitrary moment
CSMA (Carrier Sense Multiple Access)
CSMA: listen before transmit:
If channel sensed idle: transmit entire frame
• If
channel
sensed
busy,
defer
transmission
• human analogy: don’t interrupt others!
• collisions can still occur:
• propagation delay means
• two nodes may not hear
• each other’s transmission
• role of distance & propagation delay in determining
collision probability
5: DataLink Layer 5-
Persistent and Not
PersistenteCSMA
CSMA/CD (Collision Detection)
CSMA/CD: carrier sensing, deferral as in
CSMA
– collisions detected within short time
– colliding transmissions aborted,
channel wastage
reducing
• collision detection:
– easy in wired LANs: measure signal strengths,
compare transmitted, received signals
– difficult in wireless LANs: received signal
strength overwhelmed by local transmission
strength
CSMA Collision Detection
CSMA/CD can be in 3 states:
contention, transmission, or idle
Token Passing
• control token passed
T
from one node to next
sequentially.
• token message
• concerns:
• token overhead
• Latency
• single point of failure
(token)
(nothing
to send)
T
data
5-
Extra (10 points in a Final Unit)
• Make a program wich simulate Ethernet
Newtrok with collisions.
• Must be graphical (easy way) with computers
conects in a Hub or by Bus.
• The paramaters (time, persistence, frecuency)
cab be set up.
• The simulation must show the colisions and
calculate statistc
802.3 Ethernet
“dominant” wired LAN technology:
• cheap $20 for NIC
• first widely used LAN technology
• simpler, cheaper than token LANs and ATM
• kept up with speed race: 10 Mbps – 10 Gbps
Metcalfe’s
Ethernet
sketch
Ethernet: Unreliable, connectionless
• connectionless: No handshaking
sending and receiving NICs
between
• unreliable: receiving NIC doesn’t send acks or
nacks to sending NIC
– stream of datagrams passed to network layer can
have gaps (missing datagrams)
– gaps will be filled if app is using TCP
– otherwise, app will see gaps
• Ethernet’s MAC protocol: unslotted CSMA/CD
Manchester encoding
• used in 10BaseT
• each bit has a transition
• allows clocks in sending and receiving nodes to
synchronize to each other
– no need for a centralized, global clock among nodes!
• Hey, this is physical-layer stuff!
Ethernet Evolution
802.3 MAC Frame
Categories of Standard Ethernet
Encoding in a Standard Ethernet
10Base5 implementation
10Base2 implementation
10Base-T implementation
10Base-F implementation
Summary of Standard Ethernet
implementations
A network with and without a bridge
Switched Ethernet
Fast Ethernet implementations
Encoding for Fast Ethernet
Summary of Fast Ethernet
Gigabit Ethernet
Encoding in Gigabit Ethernet
Summary of Gigabit Ethernet
Summary of Ten-Gigabit Ethernet
802.4 Token Bus
•Token bus is a network implementing the token
ring protocol over a "virtual ring" on a coaxial
cable.
•A token is passed around the network nodes
and only the node possessing the token may
transmit.
•If a node doesn't have anything to send, the
token is passed on to the next node on the
virtual ring.
802.4 Token Bus
•Each node must know the address of its
neighbour in the ring, so a special protocol is
needed to notify the other nodes of connections
to, and disconnections from, the ring.
•It is mainly used for industrial applications.
Token bus was used by GM (General Motors)
for their Manufacturing Automation Protocol
(MAP) standardization effort.
802. 5 Token Ring
• Token ring is a local area network protocol
which resides at the data link layer (DLL) of the
OSI model. It uses a special three-byte frame
called a token that travels around the ring.
Token ring frames travel completely around the
loop.
• Cabling is generally IBM "Type-1" shielded
twisted pair, with unique hermaphroditic
connectors.
Token Ring
• Initially (in 1985) token ring ran at 4 Mbit/s, but
in 1989 IBM introduced the first 16 Mbit/s token
ring products and the 802.5 standard was
extended to support this.
• Token ring LANs normally use differential
Manchester encoding of bits on the LAN media.
Token Ring
Token Ring
802.6 FDDI
• Fiber distributed data interface (FDDI)
provides a standard for data transmission in a
local area network that can extend in range up
to 200 kilometers.
• These protocol is derived from the IEEE 802.4
token bus timed token protocol.
• It uses optical fiber (though it can use copper
cable, in which case one can refer to CDDI).
FDDI uses a dual-attached, counter-rotating
token ring topology.
FDDI
• A FDDI network contains two token rings, one
for possible backup in case the primary ring
fails. The primary ring offers up to 100 Mbit/s
capacity. When a network has no requirement
for the secondary ring to do backup, it can also
carry data, extending capacity to 200 Mbit/s.
The single ring can extend the maximum
distance; a dual ring can extend 100 km (62
miles).
Wireless LAN
Basic Service Sets
IEEE 802.11
Extended Service Sets
MAC Layers in WiFi
CSMA/CA with NAV
802.11 Frame Format
802.11 Control Frames
Protocol Architectures
• There are many Protocol Architectures in
Computer Network, we will discuss the
following:
•
•
•
•
TCP/IP
NetBEUI/NETBIOS
IPX/SPX
Emergent Protocols
TCP/IP
• It’s the most important Open System Network
Architecture
• TCP/IP is the fundamental basis of Internet and
WAN Networks.
• We describe in few slides about Network and
Transportation Layers.
source
message
segment
M
Ht
M
datagram Hn Ht
M
frame Hl Hn Ht
M
Encapsulation
application
transport
network
link
physical
link
physical
switch
destination
M
Ht
M
Hn Ht
Hl Hn Ht
M
M
application
transport
network
link
physical
Hn Ht
Hl Hn Ht
M
M
network
link
physical
Hn Ht
M
router
Two Key Network-Layer Functions
• forwarding:
move
analogy:
packets
from
router’s input to  routing: process of
planning trip from
appropriate router
source to dest
output
• routing: determine
route
taken
by
packets from source
to dest.
– routing algorithms
 forwarding: process of
getting through single
interchange
Forwarding table
VC number
22
12
1
Forwarding table in
northwest router:
coming interface
1
2
3
1
…
Incoming VC #
12
63
7
97
…
2
32
3
interface
number
Outgoing interface
3
1
2
3
…
Routers maintain connection state information!
Outgoing V
22
18
17
87
…
IP Fragmentation & Reassembly
•
•
network
links
have
MTU
(max.transfer size) - largest
possible link-level frame.
– different link types, different
MTUs
large IP datagram divided
(“fragmented”) within net
– one datagram becomes
several datagrams
– “reassembled” only at final
destination
– IP header bits used to
identify,
order
related
fragments
fragmentation:
in: one large datagram
out: 3 smaller datagrams
reassembly
Position of IP Protocol
IP Packet
IP Dual Stack
IP Addressing: introduction
• IP
address:
32-bit
identifier
for
host,
router interface
• interface: connection
between
host/router
and physical link
223.1.1.1
223.1.2.1
223.1.1.2
223.1.1.4
223.1.1.3
223.1.2.9
223.1.3.27
223.1.2.2
– router’s typically have
223.1.3.2
223.1.3.1
multiple interfaces
– host typically has one
interface
– IP addresses associated
223.1.1.1 = 11011111 00000001 00000001 00000001
with each interface
223
1
1
1
Subnets
• IP address:
– subnet part (high order
bits)
– host part (low order bits)
• What’s a subnet ?
– device interfaces with
same subnet part of IP
address
– can physically reach
each
other
without
intervening router
223.1.1.1
223.1.2.1
223.1.1.2
223.1.1.4
223.1.1.3
223.1.2.9
223.1.3.27
223.1.2.2
subnet
223.1.3.1
223.1.3.2
network consisting of 3 subnets
Subnets
223.1.1.2
How many?
223.1.1.1
223.1.1.4
223.1.1.3
223.1.9.2
223.1.7.0
223.1.9.1
223.1.7.1
223.1.8.1
223.1.8.0
223.1.2.6
223.1.2.1
223.1.3.27
223.1.2.2
223.1.3.1
223.1.3.2
IP addressing: CIDR
CIDR: Classless InterDomain Routing
– subnet portion of address of arbitrary length
– address format: a.b.c.d/x, where x is # bits in
subnet portion of address
host
subnet
part
part
11001000 00010111 00010000 00000000
200.23.16.0/23
IP addresses: how to get one?
Q: How does a host get IP address?
• hard-coded by system admin in a file
– Windows:
control-panel->network>configuration->tcp/ip->properties
– UNIX: /etc/rc.config
• DHCP: Dynamic Host Configuration
dynamically get address from as server
– “plug-and-play”
Protocol:
IP addresses: how to get one?
Q: How does network get subnet part of IP
addr?
A: gets allocated portion of its provider
ISP’s address space
ISP's block
200.23.16.0/20
11001000 00010111 00010000 00000000
Organization 0 11001000 00010111 00010000 00000000
200.23.16.0/23
Organization 1 11001000 00010111 00010010 00000000
200.23.18.0/23
Organization 2 11001000 00010111 00010100 00000000
200.23.20.0/23
NAT: Network Address Translation
rest of
Internet
local network
(e.g., home network)
10.0.0/24
10.0.0.1
10.0.0.4
10.0.0.2
138.76.29.7
10.0.0.3
All datagrams leaving local
network have same single source
NAT IP address: 138.76.29.7,
different source port numbers
Datagrams with source or
destination in this network
have 10.0.0/24 address for
source, destination (as usual)
IPv6
• Initial motivation: 32-bit address space
soon to be completely allocated.
• Additional motivation:
– header
format
helps
processing/forwarding
– header changes to facilitate QoS
IPv6 datagram format:
– fixed-length 40 byte header
– no fragmentation allowed
speed
IP Classes
IP Mask
IP Subnetting Analogy
Subneted Network Example
Subneted Examples
Direcciones IP (2)
Direcciones IP especiales.
Introducción a UDP
El encabezado UDP.
La cabecera del segmento TCP
Cabecera de TCP.
Microsoft Platform
• It’s the most extended PC Platform.
• First version of Windows don´t have network
conectivity.
• Novell was supported in 1993 with Windows
3.11 for Workgroup.
• TCP/IP appears with Windows 95 but it wasn´t
enable by default
NETBIOS/NETBEUI
• NetBIOS is an acronym for Network Basic
Input/Output System.
• It provides services related to the session layer
of the OSI model allowing applications on
separate computers to communicate over a
local area network.
• As strictly an API, NetBIOS is not a networking
protocol.
NETBIOS/NETBEUI
• Older operating systems ran NetBIOS over
IEEE 802.2 and IPX/SPX using the NetBIOS
Frames (NBF) and NetBIOS over IPX/SPX
(NBX) protocols, respectively. In modern
networks, NetBIOS normally runs over TCP/IP
via the NetBIOS over TCP/IP (NBT) protocol.
This results in each computer in the network
having both a NetBIOS name and an IP
address corresponding to a (possibly different)
host name.
NETBIOS/NETBEUI
• NetBIOS was developed in 1983 by Sytek Inc.
as an API for software communication over
IBM's PC-Network LAN technology.
• In 1985, IBM went forward with the token ring
network scheme and a NetBIOS emulator was
produced to allow NetBIOS-aware applications
from the PC-Network era to work over this new
design.
NETBIOS/NETBEUI
• This emulator, named NetBIOS Extended User
Interface (NetBEUI), expanded the base
NetBIOS API with, among other things, the
ability to deal with the greater node capacity of
token ring. A new networking protocol, NBF,
was simultaneously produced to allow NetBEUI
(NetBIOS) to provide its services over token
ring.
• In 1986, Novell released its own NetBIOS
emulator. Its services were encapsulated using
the NetBIOS over IPX/SPX (NBX) protocol.
NETBIOS/NETBEUI
• In 1987, a method of encapsulating NetBIOS in
TCP and UDP packets, NetBIOS over TCP/IP
(NBT), was published. It was described in RFC
1001 and RFC 1002.
• The NBT protocol was developed in order to
"allow an implementation [of NetBIOS
applications] to be built on virtually any type of
system where the TCP/IP protocol suite is
available," and to "allow NetBIOS interoperation
in the Internet."
NetBIOS/NetBEUI
• NetBIOS provides three distinct services:
• Name service
resolution.
for
• Session
service
communication.
name
for
registration
and
connection-oriented
• Datagram
distribution
service
connectionless communication.
for
NetBIOS/NetBEUI
• SMB, an upper layer, is a service that runs on
top of the Session Service and the Datagram
service, and is not to be confused as a
necessary and integral part of NetBIOS itself.
• It can now run atop TCP with a small adaptation
layer that adds a packet length to each SMB
message; this is necessary because TCP only
provides a byte-stream service with no notion of
packet boundaries.
NetBIOS/NetBEUI
• Name service
• In order to start Sessions or distribute
Datagrams, an application must register its
NetBIOS name using the Name service.
• NetBIOS names are 16 bytes in length and vary
based on the particular implementation.
Frequently, the 16th byte is used to designate a
"type" similar to the use of ports in TCP/IP.
NetBIOS/NetBEUI
• In NBT, the name service operates on UDP port
137 (TCP port 137 can also be used, but it is
rarely if ever used).
• The name service primitives offered by
NetBIOS are: Add Name, Add Group Name,
Delete Name, Find Name
• NetBIOS name resolution is not supported by
Microsoft for Internet Protocol Version 6 (IPv6).
NetBIOS/NetBEUI
• Session service
• Session mode lets two computers establish a
connection for a "conversation", allows larger
messages to be handled, and provides error
detection and recovery.
• In NBT, the session service runs on TCP port
139. The session service primitives offered by
NetBIOS are: Call, Listen, Hang Up, Send,
Send No Ack, Receive.
NetBIOS/NetBEUI
• Datagram distribution service
• Datagram mode is "connectionless". Since
each message is sent independently, they must
be
smaller;
the
application
becomes
responsible for error detection and recovery.
• In NBT, the datagram service runs on UDP port
138.The datagram service primitives offered by
NetBIOS are:Send Datagram, Send Broadcast,
Receive
Datagram,
Receive
Broadcast
Datagram.
NetBIOS/NetBEUI
• ASCII Values of 16th characters of NetBIOS
"names”
• 00: Workstation Service
• 03: Messenger Service
• 20: File Service (also called Host Record)
• 1B: Domain Master Browser - Primary Domain
Controller for a domain
• 1C: Domain Controllers for a domain (group
record with up to 25 IP addresses)
• 1D: Master Browser
• 1E: Browser Service Elections
NetBIOS/NetBEUI
• Windows Internet Name Service (WINS) is
Microsoft's implementation of NetBIOS Name
Service (NBNS), a name server and service for
NetBIOS computer names. WINS is to NetBIOS
names, what DNS is to domain names.
• The LMHOSTS (LAN Manager Hosts) file is
used to enable domain name resolution when
other methods, e.g. WINS, fail. The file can be
located
with
the
path %systemroot%\system32\drivers\etc\.
NetBIOS/NetBEUI
• Server Message Block (SMB) operates as an
application-level network protocol mainly used
to provide shared access to files, printers, serial
ports, and miscellaneous communications
between nodes on a network.
• It also provides an authenticated Inter-process
communication mechanism. Most usage of
SMB involves computers running Microsoft
Windows, where it is often known as "Microsoft
Windows Network".
NetBIOS/NetBEUI
• When discussing SMB, one should distinguish:
• the SMB protocol
• the SMB services that run on NetBIOS
• the DCE/RPC services that use SMB as an
authenticated Inter-process communication
channel (over named pipes)
• the "Network Neighborhood" protocols which
primarily (but not exclusively) run as datagram
services directly on the NetBIOS transport
NetBIOS/NetBEUI
• Microsoft launched an initiative in 1996 to
rename SMB to Common Internet File System
(CIFS), and added more features, including
support for symbolic links, hard links, larger file
sizes, and an initial attempt at supporting direct
connections over TCP port 445 without all the
NetBIOS trimmings (a largely experimental
effort that required further refinement).
• In 2006, Microsoft introduced Server Message
Block 2.0.
NetBIOS/NetBEUI
• SMB2 reduces the 'chattiness' of the protocol
by reducing the number of commands and
subcommands to 19 from over 100.
• It has mechanisms for pipelining, that is,
sending additional requests before the
response to a previous request arrives. It adds
the ability to compound multiple actions into a
single request, which significantly reduces the
number of round-trips the client needs to make
to the server, improving performance as a
result.
NetBIOS/NetBEUI
• SMB2 supports larger buffer-sizes, which can
provide better performance with large filetransfers and better use of faster networks.
• It also introduces the notion of "durable file
handles": these allow a connection to an SMB
server to survive brief network-outages, such as
may occur in a wireless network, without having
to construct a new session.
Novell Platform
• Novell is largely responsible for the use of
IPX/SPX as a popular computer networking
protocol due to their dominance in the network
operating system software market (with Novell
Netware) from the late 1980s through to the
mid-1990s.
• DOS
• Novell's original NetWare client was written for
DOS. Initial versions required a hard-linked
protocol stack, where a separate executable
would be created by the network administrator
Novell Platform
• Windows
• Because of IPX/SPX's prevalence in LANs in
the 1990s, Microsoft added support for the
protocols into Windows' networking stack,
starting with Windows for Workgroups and
Windows NT. Microsoft even named their
implementation "NWLink", implying that the
inclusion of the layer 3/4 transports provided
NetWare connectivity. In reality, the protocols
were supported as a native transport for
Windows'
SMB/NetBIOS,
and
NetWare
connectivity required additional installation.
IPX/SPX
• IPX/SPX stands for Internetwork Packet
Exchange/Sequenced Packet Exchange. IPX
and SPX are networking protocols used
primarily on networks using the Novell NetWare
operating systems.
• IPX and SPX are derived from Xerox Network
Services' IDP and SPP protocols, respectively.
IPX is a network layer protocol (layer 3 of the
OSI Model), while SPX is a transport layer
protocol (layer 4 of the OSI Model).
IPX/SPX
• The SPX layer sits on top of the IPX layer and
provides connection-oriented services between
two nodes on the network. SPX is used
primarily by client/server applications.
• IPX/SPX was primarily designed for local area
networks (LANs), and is a very efficient protocol
for this purpose (typically its performance
exceeds that of TCP/IP on a LAN).
Linux Platform
• System *X were the first Platform in using
TCP/IP Stack Protocol to communicate them.
• Exist a lot of implementation such as: Solaris,
Mac OS X, HP-UX, AIX, among others.
• Conceptually, Pltaform are very similar in
outside but internally are very diferent.
Emergent Protocols
• Emergent Protocols are new protocols widely
used in Telecomunications. One examples are
VoIP protocols (SIP, H.323, etc.)
• Most of the time, emergent protocols let they
don’t be when they are standarized and used
frecuently (they become a commodities).
• Exist a lot of Emergent Protocols and Network
Technologies, one example is Apple’s
Rendezvous, that it’s a zero network
configuration technologie (such UPnP).
Similarities and differences
between OSI and TCP/IP
models.
• This topic was discussed in Unit 1.
References
• Forouzan, B. (2008), Data Comunications and
Networking, 4th. Edition, McGraw-Hill.
• Tanenbaum, A (2004). Computer Networks. 4th
Edition. Prentice Hall.
• Kurose, J. and Ross, K. (2007) Computer
Networking:
A
Top
Down
Approach
4th edition. Addison-Wesley, July 2007.
Questions?