Transcript IPv4/6 - Rochester Institute of Technology

IPv4/6
Nirmala Shenoy
Information Technology Department
Rochester Institute of Technology
Internet Protocol
• Scope
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IPv4 Purpose / Limitations
IPv4 features
IPv6 features
MobileIP
Integrated services in IP
Differentiated services in IP
Internet Protocol
• Purpose
– To connect different types of local networks
– To provide universal communications
• Unique addresses
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To hide underlying NW technology/SW
Robust system – failures and congestion
Best effort delivery – data networks
No support for timely – reliable delivery
Internet Protocol
• Purpose
– No support for wireless networks
– Data forwarding protocols, with network ids
– No error control / flow control
• ICMP
– Connectionless datagram forwarding
Internet Protocol
• Layers
– Comprises Layer 3 functions
• Forwarding
• Routing decisions
• Uses routing algorithms
Internet Protocol
• PDU
(4-bit)
(4-bit)
Version
IHL
(8-bit) Type
of Service
(16-bit) Identification
(16-bit)
Total Length (in bytes)
(3-bit)
Flags
(8-bit)
TTL
(8-bit)
Protocol
(13-bit)
Fragment Offset
(16-bit)
Header Checksum
(32-bit) Source Address
(32-bit) Destination Address
Padding
IP Options
DATA
Internet Protocol
• PDU
– VERS: version of the IP that created the
datagram - current version is 4
– IHL : Internet header length in 32 bit words –
due to IP options
– TOTAL LENGTH: length of datagram in
octets
Internet Protocol
• PDU
– TYPE OF SERVICE
– Precedence : (importance of the datagram)
– type of transportation
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D- low delay
T – high throughput
R- high reliability
C- minimize cost
All bits 0 -normal service
– D, T, R and C help in route selection
Internet Protocol
• PDU
– IDENTIFICATION: unique id for each
datagram
– FLAGS
• D – datagram may be / may not be fragmented
• M – 0 last fragment, 1 more to come
– FRAGMMENT OFFSET
Internet Protocol
• Fragmentation and reassembly
Host B
Host A
Net 3
Net 1
MTU=1500
MTU=1500
Net 2
G1
MTU=620
G2
Internet Protocol
• PDU
– Time to Live
– PROTOCOL:
• Specifies which high level protocol was used to
create the message, - UDP, TCP
– IP OPTIONS:
• Not required in every datagram
Internet Protocol
• PDU
– 8 possible options:
0.
1.
end of options list
No operation – used for aligning octets between
options
2.
Security and handling restrictions
3.
Loose source routing
4.
Record time-stamp along a route
5.
Stream identifier (obsolete)
6.
Strict source routing
7.
Record route
Internet Protocol
• Routing in Internet
Internet
Host2
Hosts
Physical net
Gateway
Host1
Internet Protocol
• Routing in Internet
20.0.0.5
30.0.0.6
Network
Network
10.0.0.0
Dest
10.0.0.0
20.0.0.0
30.0.0.0
40.0.0.0
F
10.0.0.5
Routing Table
Next Hop
20.0.0.5
deliver direct
deliver direct
30.0.0.7
20.0.0.0
G
40.0.0.7
30.0.0.0
20.0.0.6
Network
Network
H
30.0.0.7
40.0.0.0
Internet Protocol –v6
• Why IPv6?
– IPv4 address extension using CIDR
– Real time support
– Mobility support
– Flexible and efficient
Internet Protocol –v6
• Aims of IPv6
– support huge amount of addresses
– Reduce size of routing tables
– Simplify protocol – router to process packets
faster
– Better security – authentication and privacy
– Handle type of service – real-time data
– Aid in multi-castings
– Mobility of host
– Protocol should be upgradable
– Allow for old and new protocols to co-exist
Internet Protocol –v6
• Features of IPv6
– addressing capabilities
• Address size increased from 32 to 128 bits
• More levels of address hierarchy
• Support new ‘anycast address’
– Quality of Service Capability
• Label packets for special handling during
flow
Internet Protocol –v6
• Features of IPv6
– Header Format Simplification
• Number of fields in header is reduced
• Header is of fixed length
• Fragmentation not allowed at routers
– Only source can fragment
Internet Protocol –v6
• Features of IPv6
– Improved Support for options
• Encoding of the options changed
• Router does not examine options (except
hop-by-hop options)
• More efficient forwarding
• Less stringent limits on the length
• Greater flexibility for new options
Internet Protocol –v6
• Features of IPv6
– Security
• IP level security
• Authentication and privacy supported
Internet Protocol –v6
• PDU of IPv6
4
Ver
Traffic class
12
Payload Length
16
Flow Label
Next Hdr
Source Address
Destination Address
24
31
Hop Limit
40 bytes
0
Internet Protocol –v6
• PDU of IPv6
– Priority – Traffic class
• Route choosing
• Interactive class – low delay
• Real- time – path with less than 100ms delay
Internet Protocol –v6
• PDU of IPv6
– Flow Label
• Performance guarantees
• Path establishment – id provided
• id to be used in all packets
Internet Protocol –v6
• PDU of IPv6
– Next Header – 8 bits
• Id for the header following the IPv6 header
• could identify the additional (optional)
extension headers if any
Internet Protocol –v6
• PDU of IPv6
– Next Header –
0 or more
40 octets
IPv6
Extension
Extension
Header
Header
Header
Transport-level
PDU
Header format
0
16
8
Next
Header
Hdr Ext
Length
(variable
length)
Options
Example
IPv6
header
Hop-by-hop
options header
Routing
header
TCP
header
Application
data
Internet Protocol –v6
• PDU of IPv6
– Next header
• Exists in IPv6 header and the Extension
Header
• Used to identify the next header
• Extension headers are not processed by
any node along the packet’s route (except
the hop-by-hop options header)
Internet Protocol –v6
• PDU of IPv6
– Destination options
– Fragmentation options
– Authentication
– Payload security
– Hop- by hop options
– Extended routing
Internet Protocol –v6
• Addressing in IPv6
– Unicast – an id for a single interface
– Anycast – An id for a set of interfaces
– Multicast- an id for a set of interfaces
Internet Protocol –v6
• Addressing in IPv6
– Address Representation – hex notation
• X: X: X: X: X: X: X: X
– Eg:FEDC:BA57:9874:C87B:98AC:7654:A
B56:56AB
– 1080:0:0:0:800:200C:6:417A ( leading
zeros can be omitted)
– 1080::800:200C:6:417A
Mobile Internet Protocol
• MobileIP
– Use of portable computers on the
Internet
– Internet connection on migration
– Issues
• IP addressing depends on connection to a
network
Mobile Internet Protocol
Ex: 160.80.40.20
– 160.80 – IP address class B network
number 8272
– 40.20 is the host number 10260
– Routing tables carry network id
– packets routed based on the network id
– Machine moves to a different network
• IP address changes
Mobile Internet Protocol
MobileIP Features - ietf
– Mobile host must to use its home IP address
anywhere
– No Software changes to fixed hosts
– No Changes to router software and tables
– Most packets for mobile hosts should not
make detours on the way
– No overheads while Mobile host is at home
Mobile Internet Protocol
Routing to Mobile Hosts
– Locate Host
– Forward packet to host at current
location
Mobile Internet Protocol
Routing to Mobile Hosts
– Locate Host
Wireless
Cell
Home
agent
Foreign
agent
MSC
Mobile
Host
Home
LAN
Foreign
agent
Foreign
LAN
WAN
MAN
Mobile Internet Protocol
Routing to Mobile Hosts
– Locate Host
• Identify areas – LAN, wireless networks
• Each area has a Foreign Agent, Home Agent
• Home Agent
– Responsible for roaming host
– Has the details of its current position
– Will forward messages to roaming host
Mobile Internet Protocol
Routing to Mobile Hosts
– Locate Host
• Foreign Agent
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Responsible for foreign host in its territory
Roaming Host reports to Foreign Agent
Foreign Agent communicates to Home Agent
Foreign Agent is the c/o for messages to Mobile
Host
– Broadcasts itself
Mobile Internet Protocol
Routing to Mobile Hosts
– Locate Host
• Foreign Agent
– Roaming user registers – giving its home
address
– Current data link layer address
– Security information
– FA authenticates from HA
– Gives its address as c/o for the mobile node
Mobile Internet Protocol
Routing to Mobile Hosts
– Forwarding packets
• Packets addressed to Mobile host
intercepted by HA
• HA encapsulates packet into a new IP
packet with FA as destination and itself as
Source and sends to FA – tunnelling
• FA removes encapsulation and forwards on
layer 2 to roaming mobile
Mobile Internet Protocol
Routing to Mobile Hosts
– Forwarding packets
• OR
• HA gives FA address to sender of messages
and forwards only the first message
• Subsequent messages are tunneled to FA
from Sender directly bypassing home
network
Mobile Internet Protocol
Routing to Mobile Hosts
– Forwarding packets
Wireless
Cell
Packet is tunneled to foreign agent
Home
agent
MSC
Mobile
Host
Foreign
LAN
Home
LAN
Foreign
agent
WAN
Subsequent packets are tunneled to foreign agent
Packet is sent
to Mobile
Host’s Home
address
Sender is
given foreign
agent’
senderaddress
MAN
Integrated Service in Internet
Proposed Services
– Guaranteed services
• For intolerant applications
• Faithful playback – circuit emulation
• Eg: critical control appln
Integrated Service in Internet
Proposed Services
– Predicted services
• Tolerant to Qos loss
• Predict behavior and requirement from
recent past
• Flow regulation required
– Best effort services
• Elastic Applications
Integrated Service in Internet
Proposed Services
– Achieved through
• Controlled link sharing
• Resource reservation
• Admission control
Integrated Service in Internet
Internet proposed solutions
– Stateful Solutions
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Fair queuing under congestion
Protection to well behaved traffic
Better utilisation and quality assurance
Integrated Services support - IntServ
per flow quality guarantees
Integrated Service in Internet
Internet proposed solutions
– Stateless Solutions
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Packet dropping on congestion
Identify packets into flow aggregates
Service offered on aggregated traffic
Scalable and Robust
Differentiated Services - diffserv
Integrated Service in Internet
Intserv support
– Qos Specifications
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Intserv unaware hops
Available path bandwidth
Maximum path latency
Maximum Packet size
QoS service spec – token bucket based
Integrated Service in Internet
Intserv support - Router features
Routing
Agent
Reservation
Setup Agent
Management
Agent
Admission
Control
[Routing database]
[Traffic control database]
Classifier
Packet scheduler
Input
driver
Internet
forwarder
Reference model for routers
Output driver
Integrated Service in Internet
Intserv support - Router features
– Admission Control
– Classifier
– Packet Scheduler
– Reservation set up protocols
Integrated Service in Internet
Intserv support - Router features
– Reservation set up protocols
• Helps provide sat up facilities for specific
flow demands
• Message carries application requirements
and goes though each and every router to
the end node
• If successful in providing resources
– Call accepted
• All routers enroute should handle
Integrated Service in Internet
Intserv support - Router features
– Reservation set up protocols
• Routing agents decide on the routes when
such messages come by
• Passed to Reservation set up agent
• Communicates with the admission control
• Who check if the call can be supported
• If so – reservation agents makes bookings
Integrated Service in Internet
Intserv support - Router features
– Classifier
• Classifies incoming packets into proper
queues for appropriate handling
• Classes can be one flow, multiple flows
• All packets belonging to one class are
handled identically by the scheduler
Integrated Service in Internet
Intserv support - Router features
– Packet scheduler
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Schedules based on each flow requirement
Uses queues and timers
Priority only
Weighted fair queuing
Packet dropping under congestion
Sets congestion control mechanisms
Integrated Service in Internet
Intserv support - Router features
Estimator
Measures actual outgoing traffic
Useful for the admission control
Policing
Classifying flows
Destination address, source address, ports
Flow-id – IPv6
Differentiated Service in Internet
– Packet are classified into traffic
aggregates
– Service provided to traffic aggregates
– Complexity only at boundary nodes
• Classification
• Conditioning
• Shaping
– Interior nodes – no states
Differentiated Service in Internet
– Interior nodes – no states
• Per hop behavior (PHB) defined for each
traffic class
• TOS field used as DS field – diffserv field
• Decouples service from applications
• Decouples traffic conditioning and service
provisioning from forwarding
• Scalable
• Robust
Differentiated Service in Internet
– DS domain
• Nodes operating within a common service
provisioning
• Across domains – Service Level
Agreements
Differentiated Service in Internet
– Diffserv routers
• Packet classifier
– Classfies
– Forwards to appropriate traffic conditioner
• Traffic conditioning
– Metering, shaping, policing, remarking based on
subsequent domains
Differentiated Service in Internet
– Summary
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High popularity
Limited capability
Backward compatibility
Retro-fit?
Will IPng be the solution?
Real –time support?
Wireless support?
High bit rate applications?