Ch11 Transport

8/9/2019 Ch11 Transport

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CISCO NETWORKING ACADEMYCISCO NETWORKING ACADEMY

Chabot CollegeChabot College

ELEC 99.05ELEC 99.05

Transport Layer (4)Transport Layer (4)


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TCP/IP Protocol SuiteTCP/IP Protocol Suite (simplified)(simplified)

Ethernet

IPARP

ICMP(includes Ping & Traceroute)

TCP(connectionoriented)

!TP"#$

%TTP"0

'P(connectionless)

*"5+

T!TP",9La-er

La-er /

La-er +

La-er $ & # !IToen Ring


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Layer 3 - Network LayerLayer 3 - Network Layer

1 In Cha2ters $0 & $$3 4e coered La-er

+ 2rotocols"

6 Internet Protocol (IP)1 'sed 7or addressing

6Address Resolution Protocol (ARP)

1 'sed to relate IP and MAC addresses

6 Internet Control Message Protocol (ICMP)

1 'sed 7or 2ing and traceroute co88ands


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Layer 3 - IP, !P, IC"PLayer 3 - IP, !P, IC"P

Ethernet

IPARP



!TP"#$

%TTP"0

'P(connectionless)

*"5+

T!TP",9La-er

La-er /

La-er +



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Layer 3 Limitatio#sLayer 3 Limitatio#s

1 o 4a- to assure delier- o7 2acets.

1 o 4a- to control tra77ic 7lo4 to 2reent

hosts 7ro8 eing :oer4hel8ed; -data arriing too 7ast.

1 o 4a- to ee2 trac o7 8ulti2le

conersations et4een et4een 2airso7 hosts running 8ulti2le a22lications.

(e.g. 8ail & 4e)


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Layer $ - Tra#sport LayerLayer $ - Tra#sport Layer

1 La-er / addresses these li8itations.

/


7/28CISCO NETWORKING ACADEMYCISCO NETWORKING ACADEMY

Tra#sport Layer %u#ctio#sTra#sport Layer %u#ctio#s

1 *eg8entsdata 7ro8 u22er la-era22lications.

1 'ses 2ort nu8ersto direct data to



%u#ctio#& 'ata Seme#tatio#%u#ctio#& 'ata Seme#tatio#



Tra#sport Layer ProtocolsTra#sport Layer Protocols

TCP



Layer $ - TCP *'PLayer $ - TCP *'P

Ethernet

IPARP



!TP"#$

%TTP"0

'P(connectionless)

*"5+

T!TP",9La-er

La-er /

La-er +




TCP +s *'PTCP +s *'P

1 TCP Trans8ission Control Protocol

6 connectionoriented3 reliale (irtual circuit)

6 diides outgoing 8essages into seg8ents

6 reasse8les 8essages at the destination

6 resends an-thing not receied

6 2roides 7lo4 control

6 8ore oerhead than 'P (less e77icient)



TCP +s *'PTCP +s *'P

1 'P 'ser atagra8 Protocol

6 connectionless3 unreliale3 does not

chec 8essage delier-6 sends :datagra8s;

6 does not reasse8le inco8ing 8essages

6 2roides no 7lo4 control6 lo4 oerhead 7aster than TCP



TCP a#d *'PTCP a#d *'P

1 A 2acet 4ill use either TCP or 'P3

ut not oth.

1 or8all-3 the a22lication 8aes thischoice 7or the user.



TCPTCP

Ethernet

IP


!TP"#$

%TTP"0

'P(connectionless)

*"5+

T!TP",9



*'P*'P

Ethernet

IP


!TP"#$

%TTP"0

'P(connectionless)

*"5+

T!TP",9



%u#ctio#& 'irect 'ata to%u#ctio#& 'irect 'ata to

pplicatio#spplicatio#s1 'ses 2ort nu8ers.

1 >e 4ill stud- 2orts 7urther in *e8ester #.



%u#ctio#& stalis. Co##ectio#%u#ctio#& stalis. Co##ectio#



TCP is co##ectio#-orie#tedTCP is co##ectio#-orie#ted

TCP estalis.es a co##ectio# wit.

a .ost y usi# t.e three-waythree-way

handshakehandshake



*i? its in the TCP header 2la- an

i82ortant role in estalishing3 8aintaining3

and ter8inating a connection"

URG- Urgent Pointer

ACK- Acknowledgement

PSH- Push Function

RST- Reset Request

SYN- Synchronization Request

FIN- End of Transmission arker

TCP Code 0itsTCP Code 0its

*!1

C2

PS3

!ST

S4N

%IN



TCP Code 0itsTCP Code 0its

To initiate a TCP three 4a-

handshae3 the code its are set"

*

!1

C2

P

S3

!

ST

S

4N

%IN

5 5 5 5 6 5



# 7ample TCP eader# 7ample TCP eader

TCP - Transport Control Protocol

Source Port: 2352

Destination Port:80 World Wide Web HTTP

Sequence Number: 102274726

Ac Number: 0

!""set: 7

#eser$e%: %000000

Co%e: %000010

Sync Sequence

&in%o': 8192

C(ecsum: 0x6711

)r*ent Pointer: 0

TCP !ptions:

*!1

C2

PS3

!ST

S4N

%IN





Source Port: 80 World Wide Web HTTP

Destination Port:2352

Sequence Number: 2+1,1477+

Ac Number: 102274727

!""set: 6

#eser$e%: %000000

Co%e: %010010

Ack is valid

Sync Sequence&in%o': 17520

C(ecsum: 0x9640

)r*ent Pointer: 0

TCP !ptions:

*!1

C2

PS3

!ST

S4N

%IN





Source Port: 2352

Destination Port:80 World Wide Web HTTP

Sequence Number: 102274727 Ac Number: 2+1,147.0

!""set: 5

#eser$e%: %000000

Co%e: %010000

Ack is valid

&in%o': 8760

C(ecsum: 0xd035

)r*ent Pointer: 0*!1

C2

PS3

!ST

S4N

%IN


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88sy# flood9 ttackssy# flood9 ttacks

'se ast nu8ers o7 TCP s-nchroni@ation

reuests to oer4hel8 a host.

Co%e: %000010

Synch Sequence

&in%o': 8192

C(ecsum: 0x6711

)r*ent Pointer: 0

TCP !ptions:

*

!1

C2

P

S3

!

ST

S

4N

%IN


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%u#ctio#& %low Co#trol%u#ctio#& %low Co#trol

'sed onl- - TCP.


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:i#dowi# (TCP o#ly):i#dowi# (TCP o#ly)


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:i#dow Si;e:i#dow Si;e

1 *2eci7ies nu8er o7 octetsa host is 4illing

to acce2t in the ne?t TCP seg8ent to e

sent.

1 e7ines the a8ount o7 data that can e

trans8itted 4ithout receiing an ac

(acno4ledge8ent).


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%u#ctio#& !eliaility (P!)%u#ctio#& !eliaility (P!)

1 PositieAcno4ledge8ent 4

Ch11 Transport

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