Title: Prof. Choong Seon HONG
1Local Area Networks
212? ??? ???(LAN)
- 12.1 ???? (Project) 802
- 12.2 ???(Ethernet)
- 12.3 ?? ??(Token Bus)
- 12.4 ?? ?(Token Ring)
- 12.5 FDDI (Fiber Distributed Data Interface)
3??? ???(??)
- ??????(LAN)
- ??? ???? ??(???, ??, ?? ?)? ?? ???? ?? ???? ???
???? ??? ?? ??? - LAN? ??
- ???(Ethernet)
- ?? ??(Token Bus)
- ?? ?(Token Ring)
- FDDI(Fiber Distributed Data Interface) ANSI and
ITU-T ??? - Data Link Control of LAN are based on HDLC
IEEE ???? 802 ???
412.1 ???? 802
- IEEE ??? ????(1985? ??)
- ???? 802? OSI???? ??
5???? 802 (Contd)
6???? 802 (Contd)
- IEEE 802.1
- LAN? ?????? ?? ?
- ?? ??????, ??? ? ?? ?? ????? ???? ?? ???? ??
(architecture) ?? ???? (incompatibility) ? ?? - LLC(Logical Link Control)
- IEEE 802.2
- ???????? ?????? ?? LAN ????? ??
- Containing the synchronization, flag, flow, and
error control specifications - MAC(Medium Access Control)
- ????? ??? ?? ?? ???? ?? ?????? ??
7???? 802 (Contd)
- ???? ??? ??(PDU Protocol Data Unit)
- LLC ?? ??? ??
- HDLC? ??? 4?? ??? ??
8???? 802(??)
- ??(Control) ??
- HDLC? ?? ??? ??
912.2 ???(Ethernet)
- Xerox ??? ??? 802.3 ??
- Extended by DEC, Intel, and Xerox
- IEEE 802.3
(PSK)
10???(??)
- ACCESS Method CSMA/CD
- Today the terms Ethernet, CSMA/CD, 802.3 are
used interchangeably
11???(??)
12???(??)
- ????
- ??? ?????? ? Station (pc, workstation, print ?)
? ??? NIC(Network Interface card)? ?? - 6??? ??? ??? ?? ??
13???(??)
- ?? ??
- ?? ??(Signaling)
- ?????(Baseband)??? - Manchester digital Encoding
- ?????(Broadband)??? - differential PSK
- ????(data rate)
- 1100Mbps
14???(??)
- ??? ??( Frame Format)
- Not providing any mechanism for acknowledging
received
15???(??)
- ?????
- Preamble(7???) combined the alert, timing,
start synchronization - SFD(Start frame delimiter) - ??? ??
- the everything that follows is data.
- DA(Destination address) - ??? ??
- SA(Source address) - ??? ??
- PDU ??/??
- 802.2 ???(PDU) - 461500 ?????
- CRC - ?? ?? ??, CRC-32
16???(??)
- ??(Implementation)
- 10BASE5 Thick Ethernet
- 10BASE2 Thin Ethernet
- 10BASE-T Twisted-pair Ethernet
- 1BASE5 Star LAN
- Fast Ethernet
17???(??)
- 10BASE5 Thick Ethernet(???)
18???(??)
- 10BASE5 Thick Ethernet
- RG-8 ??? 802.3 ?? backbone thick ?????
- ????(transceiver) MAU(medium attachment unit),
transmitter-receiver - AUI(attachment unit interface) ???
15-wire???(DB-15pin),???? 50m - ???? ?(Transceiver Tap) vampire tap
19???(??)
20???(??)
21???(??)
- 10BASE2 Thin Ethernet
- NIC - thick Ethernet NIC transceiver
- Thin ????? - RG-58
- BNC-T - T?? ???(3ports NIC, input, output)
22???(??)
- 10BASE2 Thin Ethernet(???)
23???(??)
- 10BASE-T Twisted-pair Ethernet
- The most popular standard defined in the IEEE
802.3 series - Star?
- UTP(Unshielded twisted pair) ???
- ???? 10 Mbps
- ???? 100M(hub to station)
- Intelligent hub ??
- Four-pair RJ-45 ???
24???(??)
- 10BASE-T Twisted-pair Ethernet(star?)
25???(??)
- 1BASE5 Star LAN
- ATT??
- ?? ???? 1 Mbps
- Twisted-pair ???
- Hub? ?? 10station
26???(??)
2712.3 Other Ethernet Networks
- An Ethernet network using a hub
28Other Ethernet Networks (contd)
- An Ethernet Network Using a Switch
29Other Ethernet Networks (contd)
- Fast Ethernet
- ?? ???? 100Mbps
- Star?
- 10base-T? ?? MAC ????? ??? ??
- 4pair category3, category5 UTP (2 pairs for
transmission and two pairs for reception) - 100BASE-X 2pair high-quality category5
- 100BASE-FX two optical fiber
- 100BASE-TX 2pair STP
30Other Ethernet Networks (contd)
- Categories of Fast Ethernet Implementations
31Other Ethernet Networks (contd)
- 100Base-Tx Implementation
32Other Ethernet Networks (contd)
The distance between the station and hub (or
switch) should be less than 2000 meters
33Other Ethernet Networks (contd)
- 100Base-T4 Implementation
- Using four pairs of category 3 (voice grade) UTP
- splitting the 100-Mbps flow of data into three
33.66-Mbps flows - Using 8B/6T
- Eight bits is transformed into six bauds of
three voltage levels (positive, negative, and
zero)
34Other Ethernet Networks (contd)
- 100Base-T4 Implementation (contd)
35Other Ethernet Networks (contd)
- Gigabit Ethernet
- 1000 bps 1 Gbps
- MAC layer and access method remain same, but the
collision domain is reduced - Physical layer transmission media and the
encoding system is changed - Used for backbone to connect Fast Ethernet
networks
36Other Ethernet Networks (contd)
37Other Ethernet Networks (contd)
- Comparison between the Gigabit Ethernet
Implementation
3812.4 ?? ??(Token Bus)
- IEEE 820.4
- ?????? ???
- Physical Configuration of Ethernet
- ????? ??? ??? ??(Ring using token)
- Using the collision-free feature of token ring
- ?? ???? ???? ??? ??
3912.5 ?? ?(Token Ring)
- IEEE 802.5
- token passing ?? access method
- Using three-byte token
- token possession
- Token ring allows each station to send one frame
per turn.
40?? ?(??)
41?? ?(??)
- ?? ?
- ????(Priority)? ??(Reservation)
- use of access control (AC) field
- ????(Time Limit) 10ms
- each station expects to receive frames within
regular time intervals - ??(monitor) station
- Monitoring, regenerating a new token
- ??
- 6 ??? ?? (imprinted on the NIC card)
42?? ?(??)
- ?? ??
- differential Manchester ???????
- ???? 4-16Mbps
- ?????
- ???(data)
- ??(token)
- ??(abort)
43?? ?(??)
44?? ?(??)
For Differential Manchester
Error Detected Bit
Control information or Data
How to use the information in the AC field
45?? ?(??)
- ?? ? ???
- SD (Start delimiter) ?? ??? ??
- used to alert the receiving station to the
arrival of a frame - equivalent to the flag field in HDLC
- adopted J and K violation to ensure
transparency in the data field - AC (Access control) ????
- Three bits priority field
- the token bit set to indicate that the frame
is a data frame rather than a token or an abort
frame - FC (Frame control) ????(??, ???)
- the first one bit used to indicate the type
of information contained in the PDU (control
information or data) - 7 bits containing information used by the
token ring logic (e.g., how to use the
information in the AC field)
46?? ?(??)
- DA(Destination address)
- SA(Source address)
- Data4500???
- CRCCRC-32 ?? ??
- ED(end delimiter)
- FS(Frame status) ???? ?? ??
- set by the receiver to indicate that the frame
has been read, or by the monitor to indicate that
the frame has been already been around the ring - So, saying that the frame can now be discarded
47?? ?(??)
- ?? ???
- 3?? ??? ?? SD, AC, ED
- used as a reservation frame to serve access to
the ring - ??(Abort) ???
- ?? ??
- Just including SD and ED
- generated either by the sender to stop its own
transmission, or by the monitor to purge an old
transmission from the line
48?? ?(??)
- Implementation
- The ring in the Token Ring consists of a series
of 150-ohm, STP sections linking each station to
its immediate neighbors
49?? ?(??)
50?? ?(??)
- MAU(Multistation Access Unit)
5112.5 FDDI (Fiber Distributed Data Interface)
- ANSI? ITU-U(ITU-TX.3) ??
- ???? ????
- Copper version of FDDI CDDI
- ???? 100Mbps
- FDDI ??
52FDDI (contd)
- Access Method Token Passing
- access is limited by allotted time
- Each station has three Time Registers to control
circulation of the token and distribute link
access opportunities among the nodes equitably. - Values are set when the ring is initialized and
do not vary in the course of operation - SA (Synchronous Allocation)
- The length of time allowed each station for
sending synchronization data (time sensitive
data) - The time value is different for each station and
is negotiated during initialization of the ring
53FDDI (contd)
- TTRT (Target Token Rotation Time)
- The average time required for a token to
circulate around ring - AMT (Absolute Maximum Time)
- A value equal to twice the TTRT
- If a token takes longer than this time to make
one rotation of the ring, the ring must be
reinitialized. - Timers
- Token Rotation Timer (TRT)
- The actual time taken by the token to complete a
cycle - Token Holding Timer (THT)
- Begins running as soon as the token is received
- Showing how much time remains for sending
asynchronous frames
54FDDI (contd)
- Station Procedure
- When a token arrives, each station follows this
procedure - THT is set the difference between TTRT and TRT
(THT TTRT TRT) - TRT is reset to zero (TRT 0)
- The station is set to zero (TRT 0)
- The station sends asynchronous data as long as
the value of THT is positive.
55FDDI (Contd)
2
56FDDI (Contd)
- Addressing
- six-byte address similar to Ethernet address
- Electronic Specification
- Signaling (physical layer)
- using a special encoding mechanism called 4B/5B
- encoding by NRZ-I
- Data Rate
- up to 100 Mbps
57FDDI (Contd)
58FDDI(??)
59FDDI(??)
60FDDI(??)
61FDDI(??)
- FDDI ? ??
- The secondary ring makes FDDI self-healing.
62FDDI(??)
- Nodes
- ?? ???(DAS dual attachment station)
- 2?? ?? ????? ???(MIC media interface
connector)? ???? 2?? ?? ?? - ?? ???(SAS single attachment station)
- ??? MIC? ??? ??? ?? ??
- ?? ????, ??, ?? ??? ?? MIC? ??? ??
- ?? ?? ???(DAC dual attachment concentrator)
- ?? ?? SAS ??
- ?? ?? ??
63FDDI(??)
6412.6 LAN ??