IP Performance Chapter 2

1
Frame Relay
Virtual Circuit
PPP link
FDDI Ring
Ethernet
Ethernet Header
PPP Header
Frame Header
FDDI Header
IP Payload
IP Payload
IP Payload
IP Payload
2
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3
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4
Version
IHL
Total Length
Type of Service
Flags
Identification
Fragment Offset
Time To Live
Protocol
Header Checksum
Source Address
Destination Address
Options
Padding
5
0
1
2
3
4
5
6
7
Precedence
Service Selector
6
0
1
2
3
4
5
6
7
Precedence
Service Selector
Precedence Field
111 - Network Control 110 - Internetwork
Control 101 - Critical functions 100 - Flash
Override 011 - Flash 010 - Immediate 001 -
Priority 000 - Routine
7
0
1
2
3
4
5
6
7
Service Selector
Precedence
0
Service Selector Field
Bits 3 - 6 1 0 0 0 minimize delay 0 1 0
0 maximize throughput 0 0 1 0 maximize
reliability 0 0 0 1 minimize monetary cost 0 0 0
0 normal best effort service bit 7 0 reserved
for future use
8
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9
IP Header
ICMP Type
ICMP Code
ICMP Checksum
ICMP
ICMP Data
ICMP Data
10
IP Header
Source Port
Destination Port
UDP
UDP Checksum
Length
UDP Data
11
10.0.0.1
10.0.0.2
OPEN 10.0.0.2, port 1000
OPEN 10.0.0.1, port 5555
SEND data SEND data SEND data
RECEIVE data
SEND data
RECEIVE data
CLOSE
CLOSE
12
Version
IHL
Total Length
Type of Service
Flags
Identification
Fragment Offset
Time To Live
Protocol 6
Header Checksum
IP Header
Source Address
Destination Address
Options
Padding
Source Port
Destination Port
TCP
Sequence Number
Acknowledgment Number
Data offset
F I N
S Y N
U R G
A C K
P S H
R S T
Window
Checksum
Urgent Pointer
Padding
TCP Options
TCP Data
13
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14
100
90
80
70
60
TCP FLOW RATE ( of maximum send rate)
50
Congestion Avoidance
40
Slow Start
30
20
10
Single Session
Two Sessions
0
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
TIME
15
Client
Server
Network
Time
Time
RECEIVE
SEND REQUEST
RECIEVE
REQUEST
1/2 RTT
WAKEUP
PROCESS REQUEST
SEND RESPONSE
1/2 RTT
RESPONSE
WAKEUP
16
Client
Server
Network
Time
Time
ACCEPT
CONNECT
SYN
1 RTT
SYN ACK
WRITE REQUEST
ACK
REQUEST DATA
1/2 RTT
READ
WAKEUP
ACK
PROCESS REQUEST
SEND RESPONSE
CLOSE
1/2 RTT
REPLY DATA
WAKEUP
FIN
CLOSE
ACK
FIN ACK
ACK
17
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18
IP Header
Source Port
Destination Port
UDP
UDP Checksum
Length
V
M
PType
P
X
CC
Sequence Number
Timestamp
RTP
Synchronization Source (SSRC) Identifier
Contributing Source (CSRC) Identifiers
RTP Payload
19
Version
Flow Label
Traffic Class
Payload Length
Hop Limit
Next Header
Source Address
Destination Address
20
Client
Server
Network
Time
Time
T Y P E
DATA T
ACK
DATA T
T Y P E
ACK
DATA Y
ACK
DATA Y
ACK
DATA P
ACK
DATA P
ACK
DATA E
ACK
DATA E
ACK
Telnet data TYPE
Echo of TYPE
21
Client
Server
Network
Time
Time
T Y P E
DATA T
DATA T ACK
T Y P E
ACK
DATA Y
DATA Y ACK
ACK
DATA P
DATA P ACK
ACK
DATA E
DATA E ACK
ACK
Telnet data TYPE
Echo of TYPE
22
Client
Server
Network
Time
Time
T Y P E
DATA T
DATA Y
T Y P E
DATA T ACK
DATA P
DATA Y ACK
DATA E ACK
DATA P ACK
ACK
DATA E ACK
ACK
ACK
Telnet data TYPE
Echo of TYPE
23
Client
Server
Network
Time
Time
T Y P E
DATA T
T Y P E
DATA T ACK
DATA YPE ACK
DATA YPE ACK
ACK
Telnet data TYPE
Echo of TYPE
24
Total window size is minimum of senders buffer
size and advertised receiver window size
Sent Data, and buffered awaiting Acknowledgement
(may be resent upon network loss)
Unsent Data, may be transmitted immediately
Sent and Acknowledged Data
Unsent Data, cannot be sent until the window opens
Received ACK advances the trailing edge of the
window
Local host advances this marker as data is
transmitted into the network
Receivers advertised window advances the leading
edge of the sliding window
The TCP Sliding Window
25
Simulation of TCP rate adaptation behavior of a
set of simultaneous TCP transfers
140
120
100
80
Relative Throughput Rate
60
40
20
0
1
51
101
151
201
Time
26
Simulation of TCP rate adaptation behavior of a
single TCP transfer
Queue size 1/3 next hop delay-bandwidth product
Duplicate ACKs received Halve cwnd to recover
160
140
Queue saturation Point
120
Slow Start (Rate doubles each RTT Interval)
Onset of queuing as rate exceeds available
capacity
100
80
Relative Throughput Rate
60
Congestion Avoidance (Rate increases by a fixed
amount each RTT Interval)
40
20
0
1
11
21
31
Time
27
Simulation of TCP rate adaptation behavior of a
single TCP transfer
Queue size 1/20 next hop delay-bandwidth product
Queue tail-drop discards burst load
140
Queue saturation Point
120
Slow Start (Rate doubles each RTT Interval)
100
Onset of queuing as rate exceeds available
capacity
80
Relative Throughput Rate
60
Restart using Slow Start
40
Timeout interval
20
0
1
11
21
31
Time
28
Input Driver Packet Assembly
Incoming Packet
Input Queue
Process Packet header
IP Forwarding Decision to select Output Interface
Outgoing Packet
Output Driver Packet Transmission
Output Queue
29
R1
R4
Link cost 5
R7
40
45
5
5
6
R6
10
20
B
R2
A
10
15
R8
Minimum path cost for A to B is 39
4
10
R3
R5
10
5
30
AS B
AS C
AS Cs routes are advertised to AS B using AS A
as transit
AS Cs routes are advertised to AS A
eBGP
eBGP
AS Cs routes transit AS A
iBGP
AS A
31
Version
IHL
Total Length
Type of Service
Flags
Fragment Offset
Identification
Time To Live
Protocol 6
Header Checksum
Source Address
Destination Address 218.130.1.1
Padding
Options
Destination Port 25
Source Port
Sequence Number
Acknowledgment Number
Data offset
U R G
A C K
F I N
S Y N
P S H
R S T
Window
Urgent Pointer
Checksum
Padding
TCP Options
TCP Data
32
X
R2
R1
Y
33
MPLS Label inserted into various encapsulation
types
MPLS Label
PPP Header
IP Header
Ethernet Header
MPLS Label
IP Header
ATM CELL
Virtual Circuit Identifier
Virtual Path Identifier
Generic Flow Control
Payload Type
Header Error Control
Congestion Loss Priority
MPLS Label
34
199.1.0.0/24
MPLS Router
4
1
MPLS Edge Router
2
1
MPLS Edge Router
MPLS Edge Router
128.10.0.0/16
6
35
S
Label
TTL
COS
MPLS Label - 20 bits
Class of Service - 3 bits
Bottom of Stack - 1 bit
Time to Live - 8 bits
36
1
1
2
2
3
3
1
2
3
4
5
1
2
3
4
5
1
4
4
5
5
MUX
DEMUX
37
Frame Relay Virtual Circuit
Frame Relay Switch
Frame Relay Switch
Frame Relay Virtual Circuit
Frame Relay Network
Frame Relay Switch
Frame Relay Switch
Frame Relay Virtual Circuit
38
Payload 1 - 2048 Octets
CRC 2 Octets
Flag 1 Octet
Flag 1 Octet
Flag 1 Octet
Q.9222 Address 2 -4 Octets
Payload 1 - 2048 Octets
CRC 2 Octets
Flag 1 Octet
Q.9222 Address 2 -4 Octets
DLCI Address bits 7 to 10 - 4 bits
FECN - 1 bit
BECN - 1 bit
DE - 1 bit
Extended Address - 1 bit
DLCI Address bits 1 to 6 - 6 bits
Command Response - 1 bit
Extended Address - 1 bit
39
Frames with Discard Eligible Bit set - due to
ingress rate exceeding CIR
Ingress Frames
1
1
1
1
Frame Relay Network
DTE
DCE
40
Queue Size
Full
Discard all Frames
Discard all Frames with DE bit set
Set FECN and BECN signal bits in Frames
Empty
41
PBX
PBX
router
router
Physical Circuit
Multiplexer
Multiplexer
Video
Video
router
router
42
Virtual Channel (VC)
Virtual Path (VP)
Physical Circuit
router
PBX
router
ATM Network
router
host
Video
PBX
router
host
Video
43
ATM Virtual Channels
ATM Virtual Paths
ATM Switch
ATM Switch
ATM Network
ATM Switch
ATM Switch
44
Public UNI
B-ICI
Public UNI
Public UNI
Public ATM Network
Public ATM Network
Private ATM Network
End-User Device
End-User Device
ATM Bearer Service QoS
45
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46
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47
Multicast Receiver
Point-to-Multipoint Virtual Circuit
ATM Switch
ATM Switch
Multicast Receiver
ATM Switch
ATM Network
ATM Switch
ATM Switch
Multicast Sender
Multicast Receiver
48
ATM
ATM
Host
Host
Router
Router
Switch
Switch
ABR Feedback Control
Loop
TCP Feedback Control Loop