2017iba lec5.ppt [互換モード] - yamanaka lab · 2017-09-25 · priority encoder destination ip...
Post on 27-Jul-2020
0 Views
Preview:
TRANSCRIPT
1
Lesson 5 Internet Protocol
Objectives :
Understanding connection-less type network architecture,
protocol and system. TCP-IP or Internet is typical connection-
less network. Basic protocols such as signaling and routing are
described.
2Fig.4.1
IP header
HeaderLengthVersion TOS Length
Identification(13 bit)
Fragment offset
TTL Protocol Checksum
Source address
Destination address
(3 bit)Flag
(4 bit) (4 bit)
Structure of IP header
IP header is used for network layer function. Packet transmission is its function.
Destination and Source address are written on the header.
3
IP address
11000001
11111111
Prefix
Mask
193.60.96.0/20193 60 96 0
255 255 240 0
prefix/mask length
255.255.255.255
D E
0.0.0.0
193.60.96.0/20193.60.0.0/16
00111100 01100000 00000000
11111111 11110000 00000000
0.0.0.0 255.255.255.255
A B C D E
Unicast
128 nets 16,384 nets 2,097,152 nets CIDR
Fig.4.2
IP address and CIDR
CIDR TECHNOLOGY → Multiple IP addresses are integrated into a single routing table.
1. The addresses share the same bits from the top of the IP address with the same bit pattern
(this is called a “prefix”).
2. The routing table 32-bit address and the 32-bit mask.
3. The routing protocol is expanded so that it can handle the 32-bit addresses and 32-bit
masks that have been introduced.
4Fig.4.3
Prefix NHR
IP forwarding table
IP header
DA=148.32.96.4148.32.0.0/16148.32.96.0/24
140.252.13.0/24129.60.0.0/16
129.60. 225.0/24 EBA
AB
224.0.0.0/16 D
Concept of “Longest prefix matching” search and the forwarding table.
Using CIDR technology, routing table becomes small. Longest prefix matching is used for packet forwarding.
5
Prefix/mask length Next hop Output port
129.66/16 129.30.166.55 3
129.66.103/24 129.30.167.13 4
176/8 129.30.168.20 6
176.10/16 129.30.169.21 5
176.10.25/24 129.30.170.169 1
Example of routing table
Table.7.2
6Fig.7.24
b d
c e g
a
f
Prefixa: 00＊b: 0001＊c: 001＊d: 0101＊e: 101＊f: 10100＊g: 111＊
0 1
0 1
0 1 0
1 1
0 1
0 1
0
1
0
1st bit
2nd bit
3rd bit
4th bit
5th bit
6th bit
101011
Trie structure
図5.4
7Fig.7.25
fb c
a d e g
Prefixa: 00＊b: 0001＊c: 001＊d: 0101＊e: 101＊f: 10100＊g: 111＊
0 1
0 101
01 1
01 11
00
Patricia tree
図5.5
8Fig.7.26
100000
101000
101010
101011
101111
111111
10101*101*1*
101101Destination address
Step-1
Step-2
Step-3
Binary search method
9Fig.7.27
Input dataOutput data（Result x）
Logic ciru
it
Entry
比較回路
比較回路
比較回路
比較回路
結果1
結果2
結果3
結果4
Reference data
Reference data
Reference data
Reference data
Comparison circuit
Comparison circuit
Comparison circuit
Comparison circuit
Result-1
Result-2
Result-3
Result-4
Typical structure of route lookup system using CAM
10Fig.7.28
129.66/16
比較回路
129.66.103/24
比較回路
比較回路
比較回路
Priority en
coder
Destination IP address
(129.66.34.40)
Output port(3)
176.10.25/24
176/8
#1
#4
#3
#6
Prefix Mask length Output port
Mask len
gth
is descen
din
g ord
er
Comparison circuit
Comparison circuit
Comparison circuit
Comparison circuit
Ternary CAM (TCAM)
11
Packet format using Ethernet header and TCP-IP header (Review)
Data
TCP header
IP header
Ethernet header
User data
Transport layer
Network layer
Data link layer
This lesson is focused on this part.
Fig.2.15
12Fig.2.16
31161040
Code BitReserved
Urgent Pointer
Window
Option
DEST PORT (destination port number)
DATA
Checksum
HLEN(header length)
ACK (acknowledgment number)
SEQ (source sequence number)
SRC PORT (source port number)
TCPheader
FIN
SYN
RST
PSH
ACK
URG
Structure of TCP header (Review)
For rate control
Port number
TCP header is used for transport layer functions. Reliable transmission, flow control and error recovery are functions.
13Fig.4.4
AS2
AS3EGP
IGPAS1
IGP and EGP（Inside-AS routing and Inter-AS routing）
Interior Gateway Protocol Exterior Gateway protocol
14Ｔable 4.1
Type Outline Example
Distance vector Seeks the next hop in the shortest route by exchanging a distance vector table (includes destination address information, etc). Bellman-Ford algorithm is used.
RIP, IGRP
Path vector Selects the route with the shortest path length that is possible to avoid a routing loop by exchanging a path vector (includes through node information to destination address, etc.)
BGP
Link state Each node has topology information by exchanging a link state and calculates the shortest route by using topology information.
OSPFIS-IS
Categorization and operation principle of routing protocol (Overview)
15Fig.4.5
Distance vector type
5276
BC
AD
Distance
Next hopDestination
B
X C
A
Only next hop router and distance to the destination are listed.
D
16Fig. 4.11
Destination=APath=D-B-A
E
F
A
B
D
C
Path vector type protocol
Set of destination and path is listed.
Path = D－B－A is the shortest path from F to A.
17Fig. 4.15
A
32
1
1
3
5
4
1
B
Source
F
1
3
Link state type routing protocol
C
E
D
Distance information from source to all nodes are calculated. This “Map” is called “Link state”.
18Table 4.2
Distance vector table (Distance vector type)
Destination Next hop Distance
129.60. 225.0/24148.32.0.0/16148.32.96.0/24224.0.0.0/16140.252.13.0/24129.60.0.0/16
EBADAB
3327
2910350
19
Concept of operation of distance vector type routing protocol
50BA
Distance
Next hopDestination
52101
BC
AA
Distance
Next hopDestination
100CA
Distance
Next hopDestination
B
X C1
2
A
Select this
50
100
Only next hop router (NHR) and distance are known.
Fig.4.5
20Fig.4.6
Bellman’s formula
i
j
D(t,i)
d(i,j)
D(t,j)
Destination
SourceD(t+1,i) = min(D(t,i), d(i,j)+D(t,j))
Shortest distance from source to destination can be determined by Bellman’s formula. It selects shorter path among alternative routes.
21Fig.4.7
ABC
Src. Dst.A (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A)B (1,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)C (2,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)A (1,A) (Inf,A) (3,C) (3,C) (5,C) (5,C) (7,C)B (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B)C (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)A (2,B) (2,B) (2,B) (4,B) (4,B) (6,B) (6,B)B (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B)C (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C)
(dist,nh)
5 6Time 1 2 3 4
A
B
C
0Detect link down
Counting to Infinity problem
22Fig. 4.8
ABC
Src. Dst.A (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A)B (1,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)C (2,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)A (1,A) (Inf,A) (Inf,C) (Inf,C) (Inf,C) (Inf,C) (Inf,C)B (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B)C (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)A (2,B) (2,B ) (2,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)B (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B)C (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C)
(dist,nh)
A
B
C
0 5 6Time 1 2 3 4Detect link down
Poison-reverse
Split horizon/Poison reverse method
23Fig. 4.9
Src. Dst.
A (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A) (0,A)B (1,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)C (2,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)D (2,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B) (Inf,B)A (1,A) (Inf,A) (Inf,A) (Inf,A) (4,C) (4,C ) (4,C) (7,C) (7,C ) (7,C)B (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B) (0,B)C (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)D (1,D) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)A (2,B) (2,B) (3,D) (3,D) (3,D) (3,D) (6,D) (6,D) (6,D) (9,D)B (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B)C (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C) (0,C)D (1,D) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)A (2,B) (2,B) (2,B) (Inf,B) (Inf,B) (5,B) (5,B ) (5,B) (8,B) (8,B)B (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B) (1,B)C (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C) (1,C)
D (0,D) (0,D) (0,D) (0,D) (0,D) (0,D) (0,D) (0,D) (0,D) (0,D)
(dist,nh)
A
C
D
0
B
5 9Time 1 2 3 4 6 87
ABC
D
Detect link down
Problem of Split horizon/Poison reverse
24
Path vector type protocol
Destination=APath=D-B-A
Destination=APath=E-B-A
Destination=APath=E-C-A
E
F
A
B
D
C
Fig.4.11
25Fig. 4.12
A
Link state L
Flooding
C E
A
B D
Concept of link state and “Flooding”
Link state information is flooding to all the nodes. Each link state table is updated by this flooding information.
26Fig. 4.15
Link state type routing protocol
1
32
1 A
1
3
5
4
1
C
B
D
dji=1
2Dj
Destination node
Q
Calculates Dj=min(Dj,dij+Di) for node-j.Determines the group of nodes Q that Dj becomes minimum.Remove it from Q
A=1 determinedRest nodes: B,C,DB=min(3,1+1)=2 → this is the smallestC=min(4,5+1)=4D=min(3,2+1)=3B=2 determined
F
1
3
E
Shortest path is found by “Dijkustra’s algorithm”
27Fig. 4.16
Example of advertising the link state
(b) Example of network LSA
D B
AC
A BLink state of router-B
A D CLink state of router-B
A BLink state of router-CB D C
Link state of router-A
D
B
A
C
Network aa
Link state of router-A
ABCD
(a) Example of router LSA
Abstracted information into one Network LSA.
28
Flooding between areas
Fig. 4.17
C
E
A
B
D
C1 C2
C3 C4C5
C6
Area 0.0.0.2
Area 0.0.0.0 (Backbone)
Area 0.0.0.1
Summary-LSA by D- prefix = A- cost = min(C1+C3, C2+C5)
Summary-LSA by C- prefix = A- cost = C2
Summary-LSA by E- prefix = A- cost = min(C1+C4, C2+C6)
Summary-LSA by B- prefix = A- cost = C1
29
Structure of LSA header
0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS age | Options | LS type |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link State ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Advertising Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS sequence number |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS checksum | length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Elapsed time from LSA occurred (0～30 min)
Currently used when OSPF Hello Database Description Indicates LSA type (Note)
Independent numeric value
Sequential number
LSA header+container value(1～65535 byte)
LSA originatingrouter ID
LSA Type=1 Router LSAType=2 Network LSAType=3 Summary LSAType=4 ASBR Summary LSAType=5 AS-External LSA
Fig. 4.18
(Note)
30
Structure of Router-LSA(Type-1, for routers connected by point-to-point)
0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS age | Options | 1 |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link State ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Advertising Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS sequence number |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS checksum | length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| 0 |V|E|B| 0 | # links |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Data |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Type | # TOS | metric |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| |
... | |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Type | # TOS | TOS metric |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Data |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| ... |
Enter the same values
ＬＳ Type=1
LSA originating router’s ID
Number of links from router
Metrics(specified with 0～65535)
Link 1
Link i
Router TypeFor example,neighboring router’s ID
Link Type(Point-to-point,Transit, Stub, Virtual link)
FlagV: VirtualE: ASBRB: ABR
Fig. 4.19(Origin) Link1 (Destination)
31
What is the metric?
Metric examples (0～65535)
1. Number of router hops (7hops)2. Distance (km)3. Number of wavelength (32 wavelength)4. Link bandwidth (1Gb/s)5. Bandwidth utilization (20%)6. Wavelength utilization / vacant number of
wavelength･･･
32
Structure of Network-LSA
Fig. 4.20
0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS age | Options | 2 |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link State ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Advertising Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS sequence number |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS checksum | length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Network Mask |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Attached Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| ... |
Enter value of DR(A)
Specify subnet mask
Enter all the routers within subnet
(A, B, C, D)
DR : Distinguished Router
ABCD
Networkα B C
DADR
33
Summary-LSA from router-A to Arena X
Fig. 4.21
0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS age | Options | 3 |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link State ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Advertising Router |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS sequence number |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| LS checksum | length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Network Mask |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| 0 | metric |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| ... |
LS Type=3 : Summary LSA
ID of router-B
Metric(C1)
ID of router-A
Mask of Area A(0.0. 0.1)
TOS=0=normal service BSummary LSA
A
C1
Area0.0.0.1
34
Concept of operation of BGP-4 （Path vector type protocol and loop detection）
Fig. 4.25
AS1
AS2AS3
10.1.1.1via AS4
10.1.1.1via AS3-AS4
10.1.1.1via AS1-AS3-AS4
10.1.1.1via AS2-AS1-AS3-AS4
IBGP
EBGP
AS4
35
Border router (BGP speaker) and BGP session
Fig. 4.26
AS1
AS2 AS3
Border router
BGP session
EBGP
IBGP
：BGP speaker：Non BGP speaker
36Fig. 4.32
Routing control of Outbound traffic using Local Ｐref attribute
R12R11
AS1
IBGP
AS4
AS2 AS3
128.213.0.0/16 128.213.0.0/16c
(Set local pref to 200)
(Set local pref to 300)
>128.213.0.0/16-- 300128.213.0.0/16-- 200
Select the route having a larger value of local pref
128.213.0.0/16
(AS1 to AS4 traffic control)
Select larger local pref value. It can create traffic control.
37Fig. 4.33
R2
R12R11
MED = 120
MED = 200
128.213.0.0/16
AS2
AS1
Use smaller MED as a speaker
Routing control of Inbound traffic using MED attribute (AS2→AS1 access control)
Please use R11 for boarder
38Fig. 4.36
EBGP
IBGPLearn routes
Don’t learn routes
IBGP is full meshed within AS
Never hops over multiple IBGP
Rule of advertising via IBGP session and EBGP session
In AS, each BGP router are connected with mesh topology.
39Fig. 4.37
Scalability
EBGP
Full mesh2
)1( NN
IBGP mesh
40Fig. 4.38
EBGPIBGP
AS1
AS2
AS3
RR
RR-Client
ＲＲ
RR-client
Route reflector
41Fig. 4.39
Sub-AS10Sub-AS12
Sub-AS11
AS confederation 1
AS2
AS3
EBGP
EIBGP
IBGP
Confederation
The AS is divided into multiple SubAS, and each SubAS functions like a single AS.
42
Conclusions for Lesson 5
To understanding connection-less protocol,detail IP networking issues were studied. ICPIP packet structure and functions wereintroduced. Basic routing protocols were alsoshown in this session.
top related