Download - IPv4/6 Nirmala Shenoy Information Technology Department Rochester Institute of Technology
Internet Protocol
• Scope– 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
– 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)
Version
(4-bit)
IHL
(8-bit) Type of Service
(16-bit)
Total Length (in bytes)
(16-bit) Identification (3-bit)
Flags
(13-bit)
Fragment Offset
(8-bit)
TTL
(8-bit)
Protocol
(16-bit)
Header Checksum
(32-bit) Source Address
(32-bit) Destination Address
IP Options Padding
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• 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
Net 2
Net 1
G1 MTU=620 G2
Net 3
Host A Host B
MTU=1500 MTU=1500
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. end of options list
1. 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
F G Network
10.0.0.0
Network
20.0.0.0 Network
30.0.0.0
Network
40.0.0.0 H
10.0.0.5
20.0.0.5
20.0.0.6
30.0.0.6
30.0.0.7
40.0.0.7
Routing Table Dest Next Hop 10.0.0.0 20.0.0.5 20.0.0.0 deliver direct 30.0.0.0 deliver direct 40.0.0.0 30.0.0.7
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
Ver Traffic class Flow Label Payload Length Next Hdr Hop Limit
Source Address
Destination Address
0 4 12 16 24 31
40 b
ytes
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 –
E x a m p l e
Hop-by-hopoptions header
Routingheader
TCPheader
Applicationdata
IPv6header
0 8 1 6 N e x t
H e a d e r H d r E x t L e n g t h
O p t i o n s
( v a r i a b l e l e n g t h )
I P v 6 H e a d e r
E x t e n s i o n H e a d e r
T r a n s p o r t - l e v e l P D U
4 0 o c t e t s 0 o r m o r e
E x t e n s i o n H e a d e r
H e a d e r f o r m a t
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:AB56:56AB
– 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
Foreign agent
Wireless Cell
Mobile Host
Foreign agent
Foreign LAN
WAN
MAN
Home LAN
MSC
Home agent
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– 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
Packet is tunneled to foreign agent
Subsequent packets are tunneled to foreign agent
Sender is given foreign agent’ address
Packet is sent to Mobile Host’s Home address
sender
Mobile Host Foreign
agent
Foreign LAN
WAN
MAN
Home LAN
Wireless Cell Home
agent MSC
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
• 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
• 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
• 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
Reference model for routers
Routing Agent
Reservation Setup Agent
Management Agent
Admission Control
[Traffic control database] [Routing database]
Classifier
Input driver
Internet forwarder Output driver
Packet scheduler
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
• 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 featuresEstimator
Measures actual outgoing traffic
Useful for the admission control
Policing
Classifying flowsDestination 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