IP Training - Leadership _ 3.0_Leadership_VF

IP Orientation Training For NSN India Delivery Leadership TeamMitrabh Shukla Head RSO IP Stream

For internal use only1 Nokia Siemens Networks

AgendaReference Architecture Context Setting

3G Network LTE Network Core PaCo Node Peering

Module 1: IP Basics IP Networking Fundamentals Reference Models - TCP/IP and OSI IP Addressing and Subnetting Fundamentals of LAN

Module 2: Switching & Routing Introduction LAN Switching


LAN Switching Spanning Tree Protocol WAN Protocols Gateway Redundancy Protocol Routing Overview (OSPF & BGP)

Module 3: MPLS Introduction MPLS (Multi Protocol Label Switching) Overview MPLS VPNs MPLS QoS MPLS Traffic Engineering MPLS High Availability

Module 4: Advance IP Features IPv6 Introduction IP Evolution Roadmap

Reference Point 1: Reference Model (OSI & TCP/IP)


Layers with TCP/IP and OSI Model

Compare OSI and TCP/IP model

A framework (guideline) for network implementation and troubleshooting

Divides complex functions into simpler components

Importance of reference model:


Vendor interoperability standardization.Better understanding of data transfer

Reference model types :OSI (Open System Interconnection ).reference modelTCP/IP (DOD Model).commercial model

Physical Layer Protocols & Services


Transport Layer

TCP

UDP


UDP

OSI Transport Layer

Objectives

1. Roles of the Transport Layer1. segmentation of data2. error detection3. Multiplexing of upper layer application using port numbers

2. The TCP protocol Communicating with reliability (TCP Header)3. TCP Connection Establishment (TCP Three -Way Handshake)


3. TCP Connection Establishment (TCP Three -Way Handshake)4. Managing TCP Sessions

1. reliability (sequencing and acknowledgements)2. In order TCP Segment Reassembly3. error correction -(TCP Retransmission)4. flow control ( window size)

5. TCP Session Termination ( 4 Way handshake)6. The UDP protocol Communicating with Low overhead (UDP Header)7. TCP VS. UDP

What is the protocol which implement transport layer ?

TCP Header UDP Header

or


Application Header + data

or

TCP Header=20 bytesUDP Header=8 bytesUDP is lower overhead

TCP Connection Establishment

When two hosts communicate using TCP, a connection is established before data can be exchanged.

After the communication is completed, the sessions are closed and the connection is terminated.

To establish the connection, the hosts perform a three-


To establish the connection, the hosts perform a three-way handshake.

Control bits in the TCP header indicate the progress and status of the connection.

TCP Connection Establishment and Termination

Within the TCP segment header, there are six 1-bit fields that contain control information used to manage the TCP processes. Those fields are: 1. URG - Urgent pointer field significant2. ACK - Acknowledgement field significant3. PSH - Push function


3. PSH - Push function4. RST - Reset the connection5. SYN - Synchronize sequence numbers6. FIN - No more data from sender

TCP Three-Way Handshake


TCP Three-Way HandshakeStep 1:A TCP client begins the three-way handshake by sending a segment with the SYN (control flag set, indicating an initial value in the sequence number field in the

header.The sequence number is the Initial Sequence Number (ISN), is randomly chosen

and is used to begin tracking the flow of data from the client to the server for this session.

Step 2:Server sends a segment back to the client with: ACK flag set indicating that the Acknowledgment number is significant.


ACK flag set indicating that the Acknowledgment number is significant. The value of the acknowledgment number field is equal to the client initial

sequence number plus 1. SYN flag is set with its own random ISN for the Sequence number

Step 3:TCP client responds with a segment containing an ACK that is the response to the

TCP SYN sent by the server. The value in the acknowledgment number field contains one more than the initial

sequence number received from the server.

TCP Session Termination

Session termination


Flow Control and ReliabilityTo govern the flow of data between devices, TCP uses a peer-to-peer flow control

Whats meant by window size


To govern the flow of data between devices, TCP uses a peer-to-peer flow control mechanism.

The receiving host's TCP layer reports a window size to the sending host's TCP layer.

This window size specifies the number of bytes, starting with the acknowledgment number, that the receiving host's TCP layer is currently prepared to receive.

Window size is included in every TCP segment sent from client or server starting with three-way handshake.

TCP is a full duplex service , client and server specify their own window sizes.

Segmentation and reassembly.

Describe the role of segments in the transport layer and the two principle ways segments can be marked for reassembly.


TCP In order ReassemblyDescribe how TCP sequence numbers are used to reconstruct the data stream with segments placed in the correct order


UDP out of order Datagram Reassembly

Describe in detail the process specified by the UDP protocol to reassemble PDUs at the destination device


TCP provides: Reliable delivery Error checking Flow control Congestion control Ordered delivery (Connection establishment) Applications:

UDP provides:Unreliable delivery

No error checking

No flow control

No congestion control

No ordered delivery

(No connection establishment)

Summary TCP vs. UDP


Applications: HTTP FTP Telnet MSN messenger

Applications

DNS (usually)

SMTP

RTP (Real-Time Protocol)

VoIP

Network Layer Protocols


Network Layer Protocols and Internet Protocol (IP)


Other IPv4 fields

Version - Contains the IP version number (4)Header Length (IHL) - Specifies the size of the packet header. Packet Length - This field gives the entire packet size, including


Packet Length - This field gives the entire packet size, including header and data, in bytes.

Identification - This field is primarily used for uniquely identifying fragments of an original IP packet

Header Checksum - The checksum field is used for error checking the packet header.

Options - There is provision for additional fields in the IPv4 header to provide other services but these are rarely used.

Grouping Devices into Networks and Hierarchical Addressing


Binary & Decimal Numbering System


Classify and Define IPv4 Addresses


IP address Classes


Subnet mask


Private IP Addresses

Private IP addresses are another solution to the problem of the impending exhaustion of public IP addresses.As mentioned, public networks require hosts to have unique IP addresses. However, private networks that are not connected to the Internet may use any host addresses, as long as each host within the private network is unique.


Subnetting


Data Link Layer Accessing the Media


Media access control addressing and framing data


The role of the trailer


Physical and Data Link Features of Ethernet

Media Access Control (MAC)


Layer 2 Header

The Frame Encapsulating the Packet


FCS


MAC Address


MAC Address Vs IP Address


Address Resolution Protocol (ARP) operation


Address Resolution Protocol ( ARP).

Mapping IP to MAC Addresses



ARP Destinations Outside the Local Network



It happens when a host ask for MAC address which isnt in the same LAN for any reason.

Router will act as a proxy


Router will act as a proxy gateway for that host.

Explain the Address Resolution Protocol (ARP) process.

ARP Removing Address Mappings


Explain the Address Resolution Protocol (ARP) process.

ARP Broadcasts - Issues


Hierarchical Network Design


Uncontrolled collision & broadcast domains


Reference Point 2: Layer 2 Switching Concepts


Three Switch Functions at Layer-2


Empty MAC table


How Switches Learn Hosts Locations


Virtual Local Area Network (VLAN)


Using spanning tree protocol (STP)


The STP Root Bridge

Reference pointOne root per VLANMaintains topology Propagates timers


How STP select the root bridge?

Firstly : choose the root bridge The lowest Bridge ID (BID)

The lowest bridge priority The lowest MAC address


Spanning tree path cost


Reference Point 3: Gateway Redundancy Protocols


HSRP (Hot Standby Routing Protocol)

HSRP, a Cisco proprietary protocol, supplies a method of providing nonstop path redundancy for IP by sharing protocol and MAC addresses between redundant gateways.

The protocol consists of a: virtual MAC address


virtual MAC address IP address These are shared between two

routers, and a process that monitors both LAN and serial interfaces via a multicast protocol.


One standby routerThe backup router in case the

active router fails for the subnet.

In that case, the standby router becomes the active router and starts forwarding traffic destined to the virtual IP address.

One virtual router The virtual router is not

an actual router. Rather, it is a concept of

the entire HSRP group acting as one virtual router as far as hosts on the subnet are concerned.

One active router The active router

forwards traffic destined to the virtual IP address.

172.16.10.82172.16.10.169

My default gateway is

172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01


The host connected to the switch sends the packet destined for the virtual router , but in reality the active router does the packet forwarding .

Note : Additional HSRP member routers Other routers are neither active nor standby, but they are configured to participate in the same HSRP group.

They monitor the current active and standby routers and transition into one of those roles if the current router fails for the subnet.

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800


172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01

HSRP Hellos: Active


The active router assumes and maintains its active role through the transmission of hello messages (default 3 seconds) .

The hello interval time defines the interval between successive HSRP hello messages sent by active and standby routers.

The router with the highest standby priority in the group becomes the active router .

The default priority for an HSRP router is 100; however, this option is configurable on a per-standby-group basis.

When the preempt option is not configured , the first router to initialize HSRP becomes the active router

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800


172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01

HSRP Hellos: Standby


The second router in the HSRP group to initialize or second highest priority is elected as the standby router .

The function of the standby router is to monitor the operational status of the HSRP group and to quickly assume packet-forwarding responsibility if the active router becomes inoperable.

The standby router also transmits hello messages to inform all other routers in the group of its standby router role and status.

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800


172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01

I receive and forward

packet sent to the virtual

router.


The virtual router presents a consistent available router (default gateway) to the hosts.

The virtual router is assigned its own IP address and virtual MAC address ; however, the active router acting as the virtual router actually forwards the packets.

Additional HSRP member routers : These routers in listen state monitor the hello messages but do not respond.

Do forward any packets addressed to the routers' IP addresses. Do not forward packets destined for the virtual router because they are not the

active router.

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800


172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01

HSRP Hellos: ActiveHSRP Hellos

I dont see Hellos from Active (10 secs), so I will

receive and forward packet sent to the

virtual router. New Active Router


When the active router fails , the other HSRP routers stop receiving hello messages and the standby router assumes the role of the active router.

This occurs when the holdtime expires (default 10 seconds) . Because the new active router assumes both the IP address and vi rtual MAC

address of the virtual router , the end stations see no disruption in service. The end-user stations continue to send packets to the virtual router's virtual MAC

address and IP address where the new active router delivers the packets to the destination.

172.16.10.82172.16.10.169


172.16.10.110

ARP Table172.16.10.110 = 0000.0c07.ac01


If both the active and standby routers fail: all routers in the HSRP group contend for the active and standby router

roles. When the active router only fails: the standby takes over. If there are other routers participating in the group, those routers then

contend to be the new standby router. The following sections discuss HSRP mechanics in more detail.

172.16.10.110 0000.0c07.ac01

172.16.10.820010.f6b3.d000

172.16.10.169 0010.0b79.5800

HSRP StatesInitial state All routers begin in the initial state. This state is entered via a

configuration change or when an interface is initiated.Learn state The router has not determined the virtual IP address , and has

not yet seen a hello message from the active router . In this state, the router is still waiting to hear from the active router.

Listen state The router knows the virtual IP address , but is neither the active router nor the standby router . All other routers participating in the HSRP group besides the active or standby routers reside in this state.

Speak state HSRP routers in the speak state send periodic hello messages and actively participate in the election of the act ive or standby router . The


and actively participate in the election of the act ive or standby router . The router remains in the speak state unless it becomes an active or standby router.

Standby state In the standby state, the HSRP router is a candidate to become the next active router and sends periodic hello messages. There must be at least one standby router in the HSRP group.

Active state In the active state, the router is currently forwarding packets that are sent to the virtual MAC and IP address of the HSRP group. The active router also sends periodic hello messages.

Not all HSRP routers transition through all states. For example, a router that is not the standby or active router does not enter the standby or active states.

VRRP

Like HSRP, VRRP is a default gateway redundancy method. VRRP enables a group of routers to form a single virtual router.

The VRRP standard (RFC 2338) solves the static default gateway configuration problem.

VRRP is similar in functionality to HSRP, and hence the LAN hosts can be configured with the virtual router as their default


hosts can be configured with the virtual router as their default gateway.

The virtual router, representing a group of routers, is known as a VRRP group.

Cisco switches and routers support VRRP on Ethernet, Fast Ethernet, and Gigabit Ethernet interfaces, and on MPLS VPNs and VLANs.

VRRP

Routers A, B, and C, are VRRP-enabled routers.

The virtual router can use a physical IP address or a virtual IP address.


Routers A, B, and C form a virtual router, with 10.0.0.1 as the virtual IP address.IP address of the virtual router is the same as that configured for the Ethernet interface of

Router A (10.0.0.1).

Because the virtual router uses the IP address of the physical Ethernet interface of ro uter A, router A assumes the role of the master virtual router and is known as the IP address owner.

As the master virtual router, router A controls the IP address of the virtual router and is responsible for forwarding packets sent to this IP address.

Hosts 1 through 3 are configured with the default gateway IP address of 10.0.0.1.Routers B and C function as backup virtual routers . If the master virtual router fails , the router configured with the higher priority will become

the master virtual router and provide uninterrupted service for the LAN hosts. When Router A recovers , it becomes the master virtual router again .

Reference Point 4: Layer 3: Routing Concepts


What is Routing?

Routing Means : Selecting the Best Path

How could you select the Best Path ? Statically Dynamically


Routing Table Structure

Routing Table is stored in ram and contains information about:

Directly connected networks - this occurs when a device is connected to another router interface Remotely connected networks - this is a network that


Remotely connected networks - this is a network that is not directly connected to a particular router Detailed information about the networks include source of information, network address & subnet mask, and Ipaddress of next-hop router

Show ip route command is used to view a routing table


Adding a connected network to the routing table-Router interfaces Each router interface is a member of a different network Activated using the no shutdown command In order for static and dynamic routes to exist in routing table you

must have directly connected networks



Connected and Static routes



Maintaining routing tables-Dynamic routing protocols are used to share routing information with other router & to maintain and up date their own routing table.

IP routing protocols. Example of routing protocols include:-RIP-IGRP-EIGRP-OSPF


-OSPF-IS-IS-BGP


Routing Table Principles-3 principles regarding routing tables: Every router makes its decisions alone, based on the information

it has in its routing table. Different routing table may contain different information A routing table can tell how to get to a destination but not how to

get back



Effects of the 3 Routing Table Principles-Packets are forwarded through the network from one router to

another, on a hop by hop basis.-Packets can take path X to a destination but return via path Y

(Asymmetric routing).


Router Paths and Packet Switching

A Metric is a numerical value used by routing protocols help determine the best path to a destination

The smaller the metric value the better the path2 types of metrics used by routing protocols are:

-Hop count - this is the number of routers a packet must travel through to get to its destination-Bandwidth - this is the speed of a link also known as the data capacity of a link



Equal cost metric is a condition where a router has multiple paths to the same destination that all have the same metric

To solve this dilemma, a router will use Equal Cost Load Balancing. This means the router sends packets over the multiple exit interfaces listed in the routing table.



Path determination is a process used by a router to pick the best path to a destination

One of 3 path determinations results from searching for the best path

Directly connected networkRemote networkNo route determined



Switching Function of Router is the process used by a router to switch a packet from an incoming interface to an outgoing interface on the same router.

-A packet received by a router will do the following:

Strips off layer 2 headers. Examines destination IP address located in Layer 3 header


Examines destination IP address located in Layer 3 header to find best route to destination. Re-encapsulates layer 3 packet into layer 2 frame. Forwards frame out exit interface.


As a packet travels from one networking device to another

- The Source and Destination IP addresses NEVER change- The Source & Destination MAC addresses CHANGEas packet is forwarded from one router to the next.


- TTL field decrement by one until a value of zero is reached at which point router discards packet (prevents packets from endlessly traversing the network)


Path determination and switching function details. PC1 Wants to send something to PC 2 here is part of what happens Step 1 - PC1 encapsulates packet into a frame. Frame contains R1s destination MAC address



Step 2 - R1 receives Ethernet frame.

R1 sees that destination MAC address matches its own MAC. R1 then strips off Ethernet frame. R1 Examines destination IP. R1 consults routing table looking for destination IP.


R1 consults routing table looking for destination IP. After finding destination IP in routing table, R1 now looks up next

hop IP address. R1 re-encapsulates IP packet with a new Ethernet frame. R1 forwards Ethernet packet out Fa0/1 interface.


Path determination and switching function details. PC1 Wants to send something to PC 2 here is part of what happens

Step 3 - Packet arrives at R2 R2 receives Ethernet frame R2 sees that destination MAC address matches its own MAC R2 then strips off Ethernet frame R2 Examines destination IP


R2 Examines destination IP R2 consults routing table looking for destination IP After finding destination IP in routing table, R2 now looks up next

hop IP address R2 re-encapsulates IP packet with a new data link frame R2 forwards Ethernet packet out S0/0 interface

Router Paths and Packet SwitchingPath determination and switching function details. PC1 Wants to send something to PC 2 here is part of what happens

Step 4 - Packet arrives at R3 R3 receives PPP frame R3 then strips off PPP frame R3 Examines destination IP R3 consults routing table looking for destination IP After finding destination IP in routing table, R3 is directly

connected to destination via its fast Ethernet interface


connected to destination via its fast Ethernet interface R3 re-encapsulates IP packet with a new Ethernet frame R3 forwards Ethernet packet out Fa0/0 interfaceStep 5 - IP packet arrives at PC2. Frame is decapsulated & processed by upper layer protocols.

Dynamic Routing Protocols

Function(s) of Dynamic Routing Protocols:-Dynamically share information between routers.-Automatically update routing table when topology changes.-Determine best path to a destination.



The purpose of a dynamic routing protocol is to:-Discover remote networks-Maintaining up-to-date routing information-Choosing the best path to destination networks-Ability to find a new best path if the current path is no longer available



Components of a routing protocolAlgorithmIn the case of a routing protocol algorithms are used for facilitating

routing information and best path determination

Routing protocol messagesThese are messages for discovering neighbors and exchange of

routing information



Advantages of static routing

-It can backup multiple interfaces/networks on a router-Easy to configure-No extra resources are needed-More secure


-More secure

Disadvantages of static routing-Network changes require manual reconfiguration -Does not scale well in large topologies

Classifying Routing Protocols

Dynamic routing protocols are grouped according to characteristics. Examples include:


Autonomous System is a group of routers under the control of a single authority.

Classifying Routing Protocols

Types of routing protocols :- Interior Gateway Protocols (IGP)- Exterior Gateway Protocols (EGP)


Why Is It Called a Link State Protocol?specific link characteristics and state information


Link State Protocol Operation

AABBCC

2213131313

QQZZXX

ZZ

YYQQ

Zs Link State

Qs Link State


Topology Information Is Kept in a Database

Separate from the Routing Table

CC 1313XX

Xs Link State

XX

Uses costs to calculate pathTypically displays faster convergence than distance vector routing protocolsTypically more scalable due to hierarchical nature

OSPF Functions and Definitions

The high-level function of OSPF is Discover neighbors and form adjacencies Flood Link State Database (LSDB) information Compute the shortest path Install routes in route forwarding tableThis section expands on these functions


This section expands on these functionsSome definitions are needed first (See text on the page with this slide)

Discovering Adjacent Neighbors

Discover neighbors with Hello packetsForm Adjacencies with appropriate neighborsExchange Link State Database (LSDB) information

using Link State Advertisements (LSA)

RID A RID B


Lets exchange information

Hello, Im B

Hello, Im A

RID A RID B

I know about these links

OK

I know about these links

Adjacency States

Sample Log showing adjacency processP1R1(config-router)#log-adjacency-changes detail

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from DOWN to INIT, Received Hello

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from INIT to 2WAY, 2-Way Received

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on


6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from 2WAY to EXSTART, AdjOK?

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from EXSTART to EXCHANGE, Negotiation Done

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from EXCHANGE to LOADING, Exchange Done

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on FastEthernet0/0 from LOADING to FULL, Loading Done

Propagate changes to maintain Link State Database synchronization

Flooding can impact

Flooding Link State Advertisements


Flooding can impact performance in large nets

Keep LSDB small!

Animated

Computing the Shortest Path Tree

The optimal path is determined by thesum of the interface costs: Cost = 108/BW

Actual Network Shortest Path Tree


10

192.213.11.0

222.211.10.0

128.213.0.08

10

5

5

10

5

192.213.11.0

222.211.10.0

128.213.0.0

10

10

10

5

5

0

5

Actual Network Shortest Path Tree

Link State Database

Router 2, Area 1

LSA

ACK

Router 1, Area 1

When a Link Changes State

Every router in an area hears a


Routing TableUpdated

Routing Table

Dijkstra Algorithmarea hears a specific link LSA

Each router computes shortest path routing table

OSPF Areas

Area 10

Area 12

Area is a group of contiguous hosts and networks

Each area has a topology database

Invisible outside the area

Area 13


RIP/RIPv2 World

Area 0

Area 11

Reduction in routing traffic

Backbone area must be contiguous

All other areas must connect to the backbone

Virtual Links

Router Types and Location

Area 10

Area 12

Area 13

Backbone Router (BR)


Autonomous System Boundary Routers(ASBR) bordering a non-OSPF area

Area Border RoutersBetween areas

RIP/RIPv2 Network

Area 0

Area 11

Internal Router (IR)Inside an area

Backbone Router (BR)Inside the core

Common Types of Link State Advertisements (LSAs)

Router link (LSA type 1)Network link (LSA type 2)Network summary (LSA type 3)ASBR Summary (LSA type 4)External (LSA type 5)NSSA external (LSA type 7)


NSSA external (LSA type 7)

Simplified Example of Different LSAs

Area 10

Area 0

External (type 5)ABR

ABR

ABR Summary (type 3)IR ABR IR

Router link (type 1)IR IR

External

ASBRExternal (type 7)ASBR IR (only in NSSA)

Network link (type 2)DR IR


RIP Network

RIP NetworkArea 11

External (type 5)ASBR IR

ABR

ASBR

DR

Animated

DR IR

ASBR Summary (type 4)ABR IR (about ASBR)

ASBR

Note: only one example of each LSA type exchange is demonstrated in this graphic

What is Border Gateway Protocol?

Used to exchange routing information between networks

BGP used internally (iBGP) and externally (eBGP)

iBGP used to carry

AS6337AS11268

AS7018


some/all Internet prefixes across backbone

customer prefixes

eBGP used to exchange prefixes with other AS's implement routing policy

AS6461

AS600

AS500

AS7018

BGP Features and Characteristics

Path Vector ProtocolIncremental UpdatesMany options for policy enforcementSupports Classless Inter Domain Routing (CIDR)Widely used for Internet backbone


What is eBGP?

Default Free Zone

Backbone ISP Backbone ISP


BGP is the routing glue that holds the entire Internet together

Enterprise Networks

Local NAP or IXP Access ISPAccess ISP

Interior vs. Exterior Routing Protocols

Interior Automatic discovery Generally trust your IGP routers Routes go to all IGP routersExterior Specifically configured peers


Specifically configured peers Connecting with outside networks Set administrative boundaries

What is an Autonomous System (AS)?

AS 100AA


Network(s) sharing the same routing policy Possibly multiple IGPs Usually under single ownership, trust and administrative control

Contiguous internal connectivityGlobally uniqueAS Number (1 to 65,535)

BGP Peering

AS 100

AS 101

AA CC

ExternalPeering

BGP speakers are called peers


100 101

AS 102

EE

BB DD

InternalPeering

AS 100

Internal BGP Peering (iBGP)

AA

BB

DD


iBGP peering is between BGP speakers in the same ASTopology independent Not required to be directly connected but must have IGP reachabilityEach iBGP speaker must peer with every other iBGP speaker in the AS

(fully meshed)They originate connected networksThey do not pass on prefixes learned from other iBGP speakers

EE

AS 100

Stable iBGP Peering


To implement stable iBGP peering: Peer with loop-back address iBGP session is not dependent on state of a single interface iBGP session is not dependent on physical topology Loop-back interface does not go down

AS 99AS 334

External BGP Peering (eBGP)

Autonomous


Between BGP speakers in different ASShould be directly connected

(peer with physical address)DO NOT run an IGP between eBGP peers

Autonomous System Border

Routers (ASBR)

Why Do We Need BGP?

Scalability Scale a large networkDivide and Conquer Implement hierarchy Implement complex policies Control reachability to prefixesStability


Stability Isolate network instability Isolate periodic IGP floodingSimplicity Merge separate organizations Connect multiple IGPs

How Does BGP Work?

Learns multiple paths via internal and external BGP speakers and stores them

Picks THE best path, installs it in the IP forwarding table Forwards all best paths to eBGP neighborsForwards external and locally originated best paths to iBGP

neighbors


neighborsPath selection is influenced by applying policies

Constructing the Forwarding Table

All

accepted

discarded

ineverything BGP

INprocess

Otherprotocols


BGPOUT

process

AllBGPpeers

forwardingtable

best pathsout

BGPtable

Best Pathselectionalgorithm

Animated

How Does BGP Advertise Routes?

Both peers attempt to connectthere is an algorithm to resolve connection collisions

AS100 AS101

AA BB


Exchange messages to open and confirm the connection parameters

Initially peers exchange entire tableOnly incremental updates after initial exchangeKeep alive messages exchanged when there no updatesBGP messages exchanged using TCP (port 179)

What are the Basic BGP Messages?

KEEPALIVE: keeps connection alive in absence of UPDATES; also ACKs OPEN

request

NOTIFICATION: reports errors in previous msg; also used to close connection Example: peer in wrong ASOPEN:


OPEN: opens TCP connection to peer and authenticates sender Exchange AS, router ID, holdtime Capability negotiationUPDATES (incremental): advertises new path (or withdraws old)

BGP States

OPEN

-1 PFXCD2 Connect3 Active


4 OpenSent

UPDATEKEEPALIVE

KEEPALIVE1 Idle

5 OpenConfirm

6 Established 0 Shutdown

Reference Point 5: MPLS (Multi Protocol Label Switching)


The Barriers


Carriers customers want IP services:

They need connectionless IP services

They need more flexible IP quality of service guarantees

They need more privacy than the Internet provides

Frame Relay and ATM services are available:

They provide connection-oriented service

They have inflexible point-to-point bandwidth guarantees

But they have good privacy

The Solution - MPLS

MULTI-PROTOCOL LABEL SWITCHINGA mechanism that delivers the best of both worlds: PRIVACY and QOS of ATM, Frame Relay FLEXIBILITY and SCALABILITY of IPFoundation for IP business services Flexible grouping of users and value-added services


Flexible grouping of users and value-added servicesLow cost managed IP services scales to large and small private networks

What Is MPLS?

Multi Protocol Label Switching

MPLS is an efficient encapsulation mechanism

Uses labels appended to packets (IP packets, AAL5 frames) for transport of data

MPLS packets can run on other Layer 2 technologies such as ATM, FR, PPP, POS, Ethernet


Other Layer 2 technologies can be run over an MPLS network

Labels can be used as designators For exampleIP prefixes, ATM VC, or a bandwidth

guaranteed path

MPLS is a technology for delivery of IP services

MPLS as a Foundation for Value-Added Services

IP+ATMIP+Optical

GMPLS

Provider Provisioned

VPNs

Traffic Engineering

Any Transport over MPLS


MPLS

Network Infrastructure

MPLS concepts

Packet forwarding is done based on labelsLabels assigned when the packet enters the networkLabels inserted between layer 2 and layer 3 headersMPLS nodes forward packets based on the label Separates ROUTING from FORWARDING


Separates ROUTING from FORWARDING Routing uses IP addresses Forwarding uses LabelsLabels can be stacked

MPLS Concepts

At Edge: Classify packets Label them Label imposition

In Core: Forward using labels

(as opposed to IP addr) Label indicates service class

and destination Label swapping or switching

Edge Label Switch Router

At Edge: Remove labels and forward

packets Label disposition


Create new services via flexible classificationProvide the ability to setup bandwidth guaranteed pathsEnable ATM switches to act as routers

Label Switch Router (LSR) Router ATM switch + label

switch controllerLabel Distribution Protocol

Router(ATM Switch or Router)

Label disposition

MPLS Operation

1a. Existing Routing Protocols (e.g. OSPF, IS-IS) Establish Reachability to Destination Networks1b. Label Distribution Protocol (LDP) Establishes Label to Destination Network Mappings

4. Edge LSR at Egress Removes Label and Delivers Packet


2. Ingress Edge LSR Receives Packet, Performs Layer 3 Value-Added Services, and Labels Packets

3. LSR Switches Packets Using Label Swapping

PPP

Ethernet

Frame Relay

Label IP header

Label

Label

IP Header

IP Header Data

ATM Header Label Data

Packet over SONET/SDH

Ethernet

Frame Relay PVC

ATM PVCs

Data

Data

IP Header

FRAME

Label Encapsulation


Label

IP Header

ATM HeaderATM PVCs

Subsequent cells Data

GFC DataVPI VCI PTI CLP HEC

GFC DataVPI PTI CLP HECVCI

Label

Subsequent cells

ATM label switching

CELL

Label Header (Shim)

Label

1 2 3 4 5 6 7 8

EXP S

TTL

Bit

2

3

4

1 Byte


TTL 4

LabelEXPSTTL

Label Value (20 bits)Class of Service (3 bits)Bottom of Stack (1 bit)Time to Live

Can be used over Ethernet, 802.3, or PPP linksEthertype 0x8847One for unicast, one for multicastFour octets per label in stack

Relevant MPLS Capabilities

The ability to FORWARD on and STACK LABELS allows MPLS to provide some useful features including:

IP+ATM Integration Provides Layer 3 intelligence in ATM switchesVirtual Private Networks


Virtual Private Networks Layer 3 Provider has knowledge of customer routing Layer 2 Provider has no knowledge of customer

routingTraffic Engineering Force traffic along predetermined paths

MPLS VPN Layer 3

Private, connectionless IP VPNsOutstanding scalabilityCustomer IP addressing freedomMultiple QoS classesSecure support for intranets and

extranets

VPN C

VPN A

VPN A

VPN BVPN C

VPN AVPN B

Connection-Oriented VPN Topology


Easy to provide Intranet/Extranet/3rdParty ASP

Support over any access or backbone technology

VPN B

VPN C

VPN AVPN B

VPN C

VPN C

VPN A

VPN B

VPN C

VPN A VPN BVPN C

VPN A

VPN BVPN C

VPN AVPN BConnectionless

VPN Topology

IP Packet VPNLabelIGPLabel

Determines PE Router

Determines VPN on PE Router

MPLS VPN Layer 2

AttachmentCircuit

L2 Frames

L2 Pseudowire/Emulated VC

Additional Capabilities:Virtual leased line service

Offer PVC-like Layer 2-based service

Reduced costconsolidate multiple core technologies into a single packet-based network infrastructure


AttachmentCircuit

Circuitnetwork infrastructure

Simpler provisioning of L2 services

Attractive to Enterprise that wish keep routing private

L2 Frame VCLabelTunnelLabel

Determines PE Router end point

Determines VC inside the tunnel

Single networkSingle networksupporting multiple VPNssupporting multiple VPNs

Separately engineeredSeparately engineeredprivate IP networks vs

Why Providers like MPLS VPN

MPLS VPNNetwork


Build once,Sell once

Build once,Sell many

Network

Traffic Engineering

Route chosen byIP routing protocol

Route specified bytraffic engineering

Why traffic engineer? Optimise link utilisation Specific paths by customer or class Balance traffic loadTraffic follows pre-specified pathPath differs from normally routed path


Path differs from normally routed pathControls packet flows across a L2 or L3

network

IP Packet VPNLabelIGPLabel

TELabel

Determines LSP next hop contrary to IGP

MPLS Components

Edge Label Switching Routers (ELSR or PE) Label previously unlabeled packets - at the beginning of a

Label Switched Path (LSP) Strip labels from labeled packets - at the end of an LSPLabel Switching Routers (LSR or P) Forward labeled packets based on the information carried by


Forward labeled packets based on the information carried by labels

MPLS Forwarding Operations

Label Imposition: add label stack to unlabeled packet (e.g. IP packet) at edge (push)

Label Forwarding: use label on packet to select next hop and label stack operation (replace, replace & push)

Label Disposition: Remove (last) label from packet (pop)


Summary

MPLS allows flexible packet classification and network resources optimisation

Labels are distributed by different protocols LDP, RSVP, BGPDifferent distribution protocols may co-exist in the same LSRLabels have local (LSR) significance


Labels have local (LSR) significance No need for global (domain) wide label allocation/numbering

Benefits of MPLS

De-couples IP packet forwarding from the information carried in the IP header of the packet

Provides multiple routing paradigms (e.g., destination-based, explicit routing, VPN, multicast, CoS, etc) over a common forwarding algorithm (label swapping)

Facilitates integration of ATM and IP - from control plane point of view an MPLS-capable ATM switch looks like a router


of view an MPLS-capable ATM switch looks like a router

RFC 2547: MPLS VPNs

VRFVRFiBGPVPNv4

Label Exchange

CE

CE


VRF

LDP LDPLDP

iBGPVPNv4 iBGPVPNv4

PE

PE

PE

CE

CE

Overlapping Addresses AreMade Unique by Appending RD and Creating VPNv4 Addresses

CE

What is an MPLS -VPN?

An IP network infrastructure delivering private network services over a public infrastructure

Use a layer 3 backbone Scalability, easy provisioning Global as well as non-unique private address space QoS


QoS Controlled access Easy configuration for customers

VPN Models

There are two basic types of design models that deliver VPN functionality

Overlay Model Peer Model


MPLS-VPN = True Peer model

MPLS-VPN is similar in operation to peer modelProvider Edge routers receive and hold routing information

only about VPNs directly connectedReduces the amount of routing information a PE router will

store


storeRouting information is proportional to the number of VPNs

a router is attached toMPLS is used within the backbone to switch packets (no

need of full routing)

MPLS VPN Connection Model

A VPN is a collection of sites sharing a common routing information (routing table)

A site can be part of different VPNsA VPN has to be seen as a community of interest (or

Closed User Group)


Closed User Group)Multiple Routing/Forwarding instances (VRF) on PE


Site-1

Site-3

Site-4

Site-2

VPN-A

VPN-C

VPN-B


A site belonging to different VPNs may or MAY NOT be used as a transit point between VPNs

If two or more VPNs have a common site, address space must be unique among these VPNs

VPN-B


The VPN backbone is composed by MPLS LSRs PE routers (edge LSRs) P routers (core LSRs)The customer router connecting to the VPN backbone is

called the Customer Edge (CE)


called the Customer Edge (CE)PE routers are faced to CE routers and distribute VPN

information through MP-BGP to other PE routers VPN-IPv4 addresses, Extended Community, Label

P routers do not run MP-BGP and do not have any VPN knowledge

PE-CE Routing

PE

CE2

CE1

PE-CE routing


PE and CE routers exchange routing information thro ugh eBGP, Static, OSPF, ISIS, RIP, EIGRP

The CE router runs standard routing software, not a ware it is connected to a VPN network

Routing Protocol Contexts

Routing processes

Routing processes run within specific routing contexts

RIP StaticBGP


VRFSite A

Routing contexts

VRF Routingtables

VRF Forwarding tables

specific routing contexts

Populate specific VPN routing table and FIBs (VRF)

Interfaces are assigned to VRFs

RIP2

RIP1

BGP3

BGP2

BGP1

VRFSite B

VRFSite C

Routing Tables

PE routers maintain separate routing tables

PE

CE2

CE1

PE-CE routingVPN Backbone IGP (OSPF, ISIS)

VRF

Global Routing Table


PE routers maintain separate routing tablesGlobal Routing Table All the PE and P routes populated by the VPN backbone IGP (ISIS or

OSPF)

VPN Routing and Forwarding Tables (VRF) Routing and Forwarding table associated with one or more directly

connected sites (CEs) VRF are associated to (sub/virtual/tunnel) interfaces Interfaces may share the same VRF if the connected sites may share the

same routing information

x

x

Route-Target and Route-Distinguisher

update X

PE1 PE2P1 P2

CE2

CE1

CE4

CE3

MP-iBGP sessionupdate X

update X

update X

VPN-IPv4 updates are


MP-BGP prepends an Route Distinguisher (RD) to each VPN route in order to make it unique

MP-BGP assign a Route-Target (RT) to each VPN route to identify VPN it belongs to (or CUG)

Route-Target is the colour of the route

VPN-IPv4 update:RD1:X, Next-hop=PE1RT=RED, Label=10

VPN-IPv4 update:RD2:X, Next-hop=PE1RT=ORANGE, Label=12

VPN-IPv4 updates are translated into IPv4 address and inserted into the VRF corresponding to the RT value

Route Propagation through MP -BGP

x

x

update X

PE1 PE2P1 P2

CE2

CE1

CE4

CE3

MP-iBGP sessionupdate X

update X

update X

VPN-IPv4 updates are


When a PE router receives an MP-BGP VPN route: It checks the route-target value to VRF route-targets If match then route is inserted into appropriate VRF The label associated with the VPN route is stored and

used to send packets towards the destination

VPN-IPv4 update:RD1:X, Next-hop=PE1RT=RED, Label=10

VPN-IPv4 update:RD2:X, Next-hop=PE1RT=ORANGE, Label=12

VPN-IPv4 updates are translated into IPv4 address and inserted into the VRF corresponding to the RT value

Multi-Protocol BGP

Propagates VPN routing information Customer routes held in VPN Routing and Forwarding tables

(VRFs)Only runs on Provider Edge P routers are not aware of VPNs only labelsPEs are fully meshed


PEs are fully meshed Using Route Reflectors or direct peerings between PE routers

MPLS VPN Protocols

OSPF/IS-IS Used as IGP provides reachability between all Label

Switch Routers (PE P PE)TDP/LDP Distributes label information for IP destinations in core


Distributes label information for IP destinations in coreMP-BGP4 Used to distribute VPN routing information between PEsRIPv2/BGP/OSPF/eiGRP/ISIS/Static Can be used to route between PE and CE

VPN Components

VRF Tables Hold customer routes at PE Route-Distinguisher Allows MP-BGP to distinguish between identical

customer routes that are in different VPNs


customer routes that are in different VPNs Route-Targets Used to import and export routes between different VRF

tables (creates Intranets and Extranets)Route-maps Allows finer granularity and control of importing

exporting routes between VRFs instead of just using route-target

MPLS VPN Operation

PPPE

CE CE

PE

= RT?= RT? RD +RD +VPN labels, RTs

SiSi SiSi

RR


MP-BGP between PE router to distribute routes betwe en VPNs

PE PE

IGP (OSPF,ISIS) used to establish reachability to d estination networks.

Label Distribution Protocol establishes mappings to IGP addresses

CECE

CE-PE dynamic routing (or static) populate the VRF routing tables

Customer routes placed into separate VRF tables at each PE

Import routes into VRF if route-targets match (expo rt = import)

RD +RD + RD +VPN labels, RTs

RR

MPLS VPN Label Stack

There are at least two labels when using MPLS-VPNThe first label is distributed by TDP/LDP Derived from an IGP route Corresponds to a PE address (VPN egress point) PE addresses are MP-BGP next-hops of VPN routesThe second label is distributed MP-BGP


The second label is distributed MP-BGP Corresponds to the actual VPN route Identifies the PE outgoing interface or routing table

Label 2 L3 Header DataLabel 1L2 Header

Frame, e.g. HDLC, PPP, Ethernet

MPLS VPN ForwardingExample

PE

PP

PE

CE CE


SiSiSiSi

PE PECECE

Push VPN Label(Red Route)

Push IGP Label(Green PE Router)

Swap IGP Label(From LFIB)

POP IGP Label(Pentultimate Hop)

Pop VPN Label(Red Route)

Motivation for Traffic Engineering

Increase efficiency of bandwidth resources Prevent over-utilised (congested) links whilst other links are

under-utilised Ensures the most desirable/appropriate path for certain traffic

types based on certain policies Override the shortest path selected by the IGP


Override the shortest path selected by the IGPThe ultimate goal is COST SAVING

The Fish Problem (Shortest Path)

R8

R2

R3

R4

R5


IP uses shortest path destination-based routing Shortest path may not be the only path Alternate paths may be under-utilized Whilst the shortest path Is over-utilized

R6 R7

R1

Shortest Path and congestion

R8

R2

R3

R4

R5

20Mbpstraffic to R5

60Mbpsaggregate

26Mbpsdrops!

OC3(155Mbps)

OC3(155Mbps)

E3(34Mbps)


R1

40Mbpstraffic to R5

R6 R7

GigE(1Gbps)

GigE(1Gbps)

GigE(1Gbps)

The TE solution

R8

R2

R3

R4

R5

20Mbpstraffic to R5

20Mbps trafficto R5 from R8

40Mbps trafficto R1 from R8


R6 R7

R1

MPLS Labels can be used to engineer explicit paths Tunnels are UNI-DIRECTIONAL

Normal path: R8 R2 R3 R4 R5Tunnel path: R1 R2 R6 R7 R4

40Mbpstraffic to R5

to R1 from R8

TerminologyConstrained-Based Shortest Path First (CSPF)

MPLS-TE uses CSPF to create a shortest path based on a series of constraints: Bandwidth Affinity/Link Attributes Priority

Tunnels are UNI-DIRECTIONAL!


Tunnels are UNI-DIRECTIONAL!

Tunnel Direction

HEADEND MIDPOINT TAILEND

Upstream Downstream

Traffic Engineering Components

Information distributionPath selection/calculationPath setupTrunk admission controlPath maintenanceForwarding traffic on to tunnel


Forwarding traffic on to tunnel

What is Quality of Service?

From a technical perspective QoS represents the set of techniques necessary to

manage network bandwidth, delay, jitter, and packet loss. From a business perspective - MANAGED FAIRNESS Critical applications are guaranteed network resources .


Critical applications are guaranteed network resources required, despite varying network traffic load The ability to enable predictive response to application traffic

.

Motivation

Offer Differentiated Services Premium-Class Service (VoIP, Stock Quotes) Business-Class Service (SAP, Oracle, Citrix) Best-Effort Service (Backups, Email)


Support for Multi-Service Networks Supporting Triple Play Services

Voice, Video, Data over IP

QoS and MPLS

MPLS does NOT define a new QoS architectureMPLS QoS uses Differentiated Services (DiffServ) architecture

defined for IP QoSDiffServ Architecture defined in RFC2475 MPLS support for DiffServ defined in RFC3270Class of Service Classification carried in


Class of Service Classification carried in COS Field of Ethernet VLAN 802.1p TOS Byte of IP Header DSCP Field of IP Header EXP Field of MPLS Header

Type of Service Field in IP Header

TOS is 8 bit field (1 byte) in the IP headerSame byte is re-defined as the DSCP

3

D T R 001 1 1 2

Prec

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


Source IP Address

VersionHeaderLength

Offset

Header ChecksumProtocolTime-to-live

Destination IP Address

Options and Padding

Total LengthType-of-Service

FlagsIdentification

EXP Field in MPLS Header

EXP is 3 bit field MPLS Label Header (also known as SHIM)

LABEL EXP TTLS


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

IETF DiffServ Model

Re-define TOS byte in IP header to Differentiated Services Code Point (DSCP) or DS Byte

Uses 6 bits to categorise traffic into Behavior Aggregates or Classes

Defines a number of Per Hop Behaviors applied to linksTwo-Ingredient Recipe:


Two-Ingredient Recipe: Condition the Traffic at the Edges Invoke the PHBs in the Core

Differentiated Services Architecture (RFC 2745)

Ingress Node

Interior Node

Egress Node

TCAPHB

PHB TCAPHB

DiffServ DomainDiffServ Domain DiffServ Domain


Traffic Conditioning Agreement (TCA)

Classification/Marking/Policing/Shaping

Per-Hop Behavior (PHB)

Queuing/Dropping

DiffServ Terminology

PHB Per Hop Behavior The DiffServ treatment (scheduling/dropping) applied by a Router to all the

packets which are to experience the same DiffServ serviceDSCP Differentiated Services Code Point The value in the IP Header indicating which PHB is to be applied to the

packetBA Behaviour Aggregate The set of all the packets which have the same DSCP (and thus that will


The set of all the packets which have the same DSCP (and thus that will receive the same PHB)

OA Ordered Aggregate The set of BAs which have an ordering constraint (must go into the same

queue)PSC PHB Scheduling Class The set of PHBs applied to an OA (the set of PHBs using the same

queue)

DiffServ Terminology - How they fit together

BA AF11

BA AF12

OA

Queue for AF1x(Bronze Class)

PHB

PHB

PSCPackets with AF markings

Drop Probabilities within the queue


Link

BA AF13 PHB

BA AF21

BA AF22

BA AF23

Queue for AF2x(Sliver Class)

PSCOA Packets with AF markings

PHB

PHB

PHB

Per-Hop Behaviors (PHB)

Expedited Forwarding (EF) Building block for low delay/jitter/loss Served at a certain rate with short/empty queuesAssured Forwarding (AF) High probability of delivery if profile is not exceeded Four classes and three levels of drop precedence


Four classes and three levels of drop precedence Specific resources (BW, buffer space) allocated to each class

at each nodeBest Effort (BE)

BEBEAF1AF1AF3AF3 AF2AF2AF4AF4EFEF

DiffServ Classes (DSCP Values)

Priority

Low Drop AF11

101110 (46)

AF21AF31AF41

High LowPriority Classes

Dro

p P

roba

bilit

y

Low


Low DropAFx1

AF11001010 (10)

BestEffort

000000

Med DropAFx2

High DropAFx3

AF21010010 (18)

AF31011010 (26)

AF41100010 (34)

AF12001100 (12)

AF22010100 (20)

AF32011100 (28)

AF42100100 (36)

AF13001110 (14)

AF23010110 (22)

AF33011110 (30)

AF43100110 (38)

High

Dro

p P

roba

bilit

y

Reference Point 6: IP Evolution IPv6 & Strategy


An IPv4 packet walks into a bar and says Give me a CIDR, Im exhausted

An IPv6 packet walks into a bar and complains I cant get a drink because not many people understand me


3rd February 2011 The last five remaining /8 pools were allocated amongst the five Regional Internet Registries

The Day The Earth Stood Still Hey Buddy,Can you spare

an IPv4 address?


Announcement by ICCAN Available Pool of Unallocated IPv4 Internet Addresses Now

Completely Emptied

Source: http://www.icann.org/en/news/releases/release-03feb11-en.pdf

Where Did All the IPv4 Go?

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It Is Not Just About IPv4 ExhaustionThere are arguably two intertwined problemsExhaustion of Global and Private IPv4 address space Addressed by IPv6 and stop gap measures such as NAT, CIDR Available AS number pool also shrinking (hence 32 bit AS numbers) Private RFC1918 space is not big enough for many SPsGrowing size of the Internet routing table

July 2010 Feb 2011


As IPv6 grows aggregation is desirable (PI vs PA)

Source: http://bgp.potaroo.net APNIC R&D 25 Feb 2011

July 2010 Feb 2011

IPv4 BGP Entries 328,598 350,103

IPv6 BGP Entries 3114 4752

What Are The Drivers To Move To IPv6?

IPv4 address pool exhaustedNGN Capabilities to DefenceGovernment MandatesCable market address scalingPopulation densities in APAC4G deployments

IPv6 is an enablerIt is NOT a new serviceIt allows anything to connect to everything


4G deploymentsSmart Grids/Sensor NetworksConnected CommunitiesIPv4 connects computersIPv6 connects people and things

Technical Benefits of IPv6 Huge address space Simplified header format Efficient packet handling fields moved out of header or

eliminated Checksum removed, Fragmentation moved to end hosts Hierarchical network architecture Routing efficiency high level of aggregation possible


Routing efficiency high level of aggregation possible Auto configuration and plug-and-play support Some reduction in the need for network address translation Optimized for Internet mobile applications New types of peer to peer applications Increased number of multicast addresses Flow labels for QoS

IPv4 and IPv6 Header Comparison

Fragment OffsetFlags

Total LengthType of ServiceIHL

Source Address

Header ChecksumProtocolTime to Live

Identification

Version

IPv4 Header

Next Header Hop Limit

Flow LabelTraffic Class

Payload Length

Version

IPv6 Header


PaddingOptions

Destination Address

Source Address

Destination Address

Source Address

Fields Name Kept from IPv4 to IPv6

Fields Not Kept in IPv6

Name and Position Changed in IPv6

New Field in IPv6Leg

end

IPv6 Addresses

IPv6 addresses are 128 bits long Segmented into 8 groups of four HEX characters Separated by a colon (:) 50% for network ID, 50% for interface ID Network portion is allocated by Internet registries 2^64 (1.8 x 1019) Still leaves us with ~ 3 billion network prefixes for each person on earth

Network Portion Interface ID

Global Unicast Identifier Example


gggg:gggg:gggg:ssss:

xxxx:xxxx:xxxx:xxxx

Global Routing Prefixn

Integration or Migration?

IPv4+IPv6CoreIPv4+IPv6Core

CEIPv6IPv6

PE P P PE

CE IPv6IPv6

IPv6 + IPv4Integration

ApplicationMigration

ApplicationMigration


Some applications at the edge will MIGRATE to IPv6

Network infrastructures will INTEGRATE IPv6 IPv4 will be around for a very long time

Networks will support both protocols

Many hardware components will be dual-stack capable (IPv4+IPv6)

IPv6 is a gradual and controlled process of INTEGRATION

IPv6 Planning Steps

Establish IPv6projectmanagement team

2Evaluate effecton businessmodel

1Assess networkhardware andsoftware

3

Business Case Identified/Justified


IPv6 Trainingstrategy 4

Decide IPv6architecturalsolution

6Developsecuritypolicy

8

Develop IPv6exceptionstrategy

10

Obtain IPv6prefix(es) 5

Test applicationsoftware andservices

7

Developprocurementplan

9

IPv6 Deployment OptionsIPv6 Only

IPv6 is the only protocol operating in the network

Dual Stack (in devices/hosts and networks)

IPv4 and IPv6 operate in tandem over shared or dedicated links

IPv6IPv6 IPv6

IPv6IPv6

IPv4

IPv6 IPv6

IPv4 SharedLinks

Applications DualStack Aware


Tunnelling over IPv4 or MPLS

IPv6 confined to the edge of the IPv4 / MPLS coreIPv6

IPv4

IPv4/MPLS

IPv4

Dedicated Links

Tunnel

IPv4/MPLS

Protocol Translation (Moving to Experimental in IETF)

Allow IPv6-only devices to communicate with IPv4-only devices

Thank You!


IP Training - Leadership _ 3.0_Leadership_VF

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