IPV6 QUICK REFERENCE WITH QUESTIONS AND ANSWER:

IPV6 ADDRESSES URLS:

Ipv6 Addresses Can Also Be Referenced In URLs (Uniform Resource Locator). URL’s, However, Use The Colon To Represent A Specific TCP “Port”. This Is Not An Issue With Ipv4 Addresses, Which Can Easily Be Referenced Using A URL:

Http://192.168.1.1/Index.Html

Because IPv6 Fields Are Separated By Colons, The Ipv6 Address Must Be Placed In Brackets, To Conform To The URL Standard:

Http://[FEC0::CC1E:2412:1111:2222:3333]/Index.Html

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IPV6 ADDRESS HEADER

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An Internet Protocol Version 6 (Ipv6) Data Packet Comprises Of Two Main Parts: The Header And The Payload. The First 40 Bytes/Octets (40x8 = 320 Bits) Of An Ipv6 Packet Comprise Of The Header (See Figure) That Contains The Following Fields:



Version (4-Bits): This Represents The Version Of Internet Protocol, I.E. 0110.

Traffic Class (8-Bits): These 8 Bits Are Divided Into Two Parts. Most Significant 6 Bits Are Used For Type Of Service, Which Tells The Router What Services Should Be Provided To This Packet. Least Significant 2 Bits Are Used For Explicit Congestion Notification (ECN).

Flow Label (20-Bits): This Label Is Used To Maintain The Sequential Flow Of The Packets Belonging To A Communication. The Source Labels The Sequence Which Helps The Router To Identify That This Packet Belongs To A Specific Flow Of Information. This Field Helps To Avoid Re-Ordering Of Data Packets. It Is Designed For Streaming/Real-Time Media.

Payload Length (16-Bits): This Field Is Used To Tell The Routers How Much Information This Packet Contains In Its Payload. Payload Is Composed Of Extension Headers And Upper Layer Data. With 16 Bits, Up To 65535 Bytes Can Be Indicated But If Extension Headers Contain Hop-By-Hop Extension Header Than Payload May Exceed 65535 Bytes And This Field Is Set To 0.

Next Header (8-Bits): This Field Is Used To Indicate Either The Type Of Extension Header, Or If Extension Header Is Not Present Then It Indicates The Upper Layer PDU. The Values For The Type Of Upper Layer PDU Is Same As IPv4’s.

Hop Limit (8-Bits): This Field Is Used To Stop Packet To Loop In The Network Infinitely. This Is Same As TTL In Ipv4. The Value Of Hop Limit Field Is Decremented By 1 As It Passes A Link (Router/Hop). When The Field Reaches 0 The Packet Is Discarded.

Source Address (128-Bits): This Field Indicates The Address Of Originator Of The Packet.

Destination Address (128-Bits): This Field Provides The Address Of Intended Recipient Of The Packet.

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IPV6 ROUTING PROTOCOLS

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RIPng: RIPng Stands For Routing Information Protocol Next Generation. This Is An Interior Routing Protocol And Is A Distance Vector Protocol. RIPng Has Been Upgraded To Support IPv6.

OSPFv3: Open Shortest Path First Version 3 Is An Interior Routing Protocol Which Is Modified To Support Ipv6. This Is A Link-State Protocol And Uses Djikrasta’s Shortest Path First Algorithm To Calculate Best Path To All Destinations.

BGPv4: BGP Stands For Border Gateway Protocol. It Is The Only Open Standard Exterior Gateway Protocol Available. BGP Is A Distance Vector Protocol Which Takes Autonomous System As Calculation Metric, Instead Of Number Of Routers As Hop. BGPv4 Is An Upgrade Of BGP To Support Ipv6 Routing.

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IPV6 SUPPORT PROTOCOLS

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ICMPv6: Internet Control Message Protocol Version 6 Is An Upgraded Implementation Of ICMP To Accommodate Ipv6 Requirements. This Protocol Is Used For Diagnostic Functions, Error And Information Message, Statistical Purposes. Icmpv6’s Neighbor Discovery Protocol Replaces ARP And Helps Discover Neighbor And Routers On The Link.

DHCPv6: Dynamic Host Configuration Protocol Version 6 Is An Implementation Of DHCP. Though Ipv6 Enabled Hosts Do Not Require Any Dhcpv6 Server To Acquire IP Address As They Can Be Auto-Configured. Neither Do They Need Dhcpv6 To Locate DNS Server Because DNS Can Be Discovered And Configured Via Icmpv6 Neighbor Discovery Protocol. Yet Dhcpv6 Server Can Be Used To Provide These Information.

DNS: There Has Been No New Version Of DNS But It Is Now Equipped With Extensions To Provide Support For Querying Ipv6 Addresses. A New AAAA (Quad-A) Record Has Been Added To Reply Ipv6 Query Messages. Now DNS Can Reply With Both IP Versions (4 & 6) Without Any Change In Query Format.

NEIGHBOR DISCOVERY PROTOCOL (NDP) The Neighbor Discovery Protocol (NDP) Provides A Multitude Of Services For IPv6 Enabled Devices, Including:

• Automatic Address Configuration, And Prefix Discovery
• Duplicate Address Detection
• MTU Discovery
• Router Discovery
• Address Resolution

NDP Replaces Many Ipv4 Specific Protocols, Such As DHCP And ARP. NDP Utilizes ICMPv6 To Provide The Above Services.

Periodically, IPv6 Routers Send Out Router Advertisements (RA’s) To Both Announce Their Presence On A Link, And To Provide Auto-Configuration Information For Hosts. This RA (ICMP Packet Type 134) Is Sourced From The Link-Local Address Of The Sending Router, And Sent To The Link-Scope All-Nodes Multicast Group. The Sending Router Sets A Hop Limit Of 255 On A RA; However, The RA Packet Must Not Be Forwarded Outside The Local Link. Hosts Use RA’s To Configure Themselves, And Add The Router To Its Local Default Router List. A Host Can Request An RA By Sending Out A Router Solicitation (RS, ICMP Packet Type 133) To The Link-Local All-Routers Multicast Address. A RS Is Usually Sent When A Host Is Not Currently Configured With An IP Address.

The RA Messages Contain The Following Information For Hosts:

• The Router’s Link-Layer Address (To Be Added To The Host’s Default Router List)
• One Or More Network Prefixes
• A Lifetime (Measured In Seconds) For The Prefix(Es)
• The Link MTU

Routers Send Redirect Messages To Hosts, Indicating A Better Route To A Destination. Hosts Can Have Multiple Routers In Its Default Router List, But One Is Chosen As The True Default Router. If This Default Router Deems That Another Router Has A Better Route To The Destination, It Forwards The Redirect Message To The Sending Host.

Neighbor Solicitations (NS’s, ICMP Packet Type 135) Are Sent By Hosts To Identify The Link-Layer Address Of A Neighbor, And Ensure Its Reachability. A NS Message’s Source Address Is The Link-Local Address Of The Sending Host, And The Destination Is The Solicited-Node Multicast Address Of The Destination Host.

A Neighbor Will Reply To A NS With A Neighbor Advertisement (NA, ICMP Packet Type 136). This Process Replaces The Address Resolution Protocol (ARP) Used By IPv4, And Provides A Far More Efficient Means To Learn Neighbor Address Information.

Hosts Additionally Use The NS Messages To Detect Duplicate Addresses. Before A Host Assigns Itself An IPv6 Address, It Sends Out A NS To Ensure No Other Host Is Configured With That Address.

AUTOCONFIGURATION OF HOSTS: Hosts Can Be Assigned Ipv6 Addresses One Of Two Ways: Manually, Or Using Autoconfiguration. Hosts Learn How To Autoconfigure Themselves From Router Advertisements (RA’s).

Two Types Of Autoconfiguration Exist, Stateless And Stateful.

When Using Stateless Autoconfiguration, A Host First Assigns Itself A Linklocal IPv6 Address. It Accomplishes This By Combining The Link-Local Prefix (FE8) With Its Interface ID (MAC Address In EUI-64 Format).

The Host Then Sends A Router Solicitation Multicast To The All-Routers Multicast Address, Which Provides One Or More Network Prefixes. The Host Combines These Prefixes With Its Interface ID To Create Its Site-Local (Or Aggregate Global) IPv6 Addresses.

Stateful Autoconfiguration Is Used In Conjunction With Stateless Autoconfiguration. Stateful Autoconfiguration Utilizes DHCPv6 To Provide Additional Information To The Host, Such As DNS Servers. DHCPv6 Can Also Be Used In The Event That There Is No Router On The Link, To Provide Stateless Autoconfiguration.

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IPV6 CONFIGURING EXAMPLES

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IPv6 Support Is Disabled By Default On Cisco Routers, And Must Be Enabled Globally:

Router(Config)# IPv6 Unicast-Routing

To Configure An Interface To Auto-Configure A Link-Local IPv6 Address:

Router(Config)# Interface E0
Router(Config-If)# IPv6 Enable

To Manually Configure A Site-Local IPv6 Address On An Interface:

Router(Config)# Interface E0
Router(Config-If)# IPv6 Address FEC0::/64 Eui-64

The EUI-64 Parameter Will Append Interface ID (MAC Address In EUI-64 Format) To The Site-Local Prefix. Otherwise, We Could Have Specified The Full IPv6 Address:

Router(Config-If)# IPv6 Address FEC0::1:1234:23FF:FE21:1212 Eui-64

Recall That We Can Configure Multiple Subnets For Our Site-Local Address Space:

Router(Config)# Interface E0
Router(Config-If)# IPv6 Address FEC0::2222:0:0:0:0/64 Eui-64

To Configure A Router Interface To Advertise A Specific Prefix To Hosts On The Link:

Router(Config)# Interface E0
Router(Config-If)# IPv6 Nd Prefix-Advertisement 2002:1111::/48 2000 1000 Onlink Autoconfig

The Router Will Advertise A Prefix Of 2002:1111::/48 With A Valid Lifetime Of 2000 Seconds And A Preferred Lifetime Of 1000 Seconds. The Clients Will Autoconfig Themselves Based On This Prefix.

To View IPv6 Specific Information About An Interface:

Router# Show IPv6 Interface E0

To Create A Static Host Entry For An IPv6 Address:

Router(Config)# IPv6 Host MYHOST FEC0::1111:2731:E2FF:FE96:C283

IPV6 STATIC ROUTES:

The Syntax To Configure An IPv6 Static Route Is Simple:

Router(Config)# IPv6 Route FEC0::2222/64 FEC0::1111:3E5F:2E5B:A3D1

The Above Command Creates An IPv6 Route To The FEC0::2222/64 Network, With A Next-Hop Of FEC0::1111:3E5F:2E5B:A3D1.

To Create An IPv6 Default Route:

Router(Config)# IPv6 Route ::/0 FE80::2

The Above Command Creates An IPv6 Default Route, With A Next Hop Of FE80::2. The ::/0 Designation Indicates All Zeros In The Address Field, And A Mask Of Zero Bits (The Unspecified Address).

To View The IPv6 Routing Table:

Router(Config)# Show IPv6 Route

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IPv6 QUESTIONS & ANSWER

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1. WHAT IS THE LENGTH OF AN IPV6 ADDRESS?

IPv6 Addresses Are 128 Bits In Length.

2. HOW ARE IPV6 ADDRESSES REPRESENTED?

IPv6 Addresses Are Represented As Eight 16-Bit Hexadecimal Segments Separated By Colons.

3. WHAT ARE THE TWO RULES FOR COMPACTING IPV6 ADDRESSES?

The Two Rules For Compacting IPv6 Addresses Are

A. The Leading Zeroes In Any 16-Bit Segment Do Not Have To Be Written.

B. Any Single, Continuous String Of One Or More 16-Bit Segments Consisting Of All Zeroes Can Be Represented With A Double Colon.

4. WHY IS IT ILLEGAL TO USE MORE THAN ONE DOUBLE COLON IN AN IPV6 ADDRESS?

Using More Than One Double Colon Ambiguates The Address; The Exact Length Of Each String Of Zeroes Cannot Be Determined.

5. WHAT IS THE DIFFERENCE BETWEEN THE IPV6 ADDRESSES ::/0 AND ::/128?

Both Addresses Are All Zeros. ::/0 Is The Default Address, Whereas ::/128 Is The Unspecified Address.

6. WHAT IS THE PART OF THE UNICAST IPV6 ADDRESS THAT SPECIFIES THE HOST, AND WHAT IS ITS LENGTH?

The Part Of A Unicast IPv6 Address That Specifies The Host Is The Interface ID, And It Is Usually 64 Bits In Length.

7. WHAT IS THE LENGTH OF THE SUBNET ID PORTION OF THE UNICAST IPV6 ADDRESS?

The Subnet ID Of The Unicast IPv6 Address Is 16 Bits Long.

8. IF THE FIRST 10 BITS OF AN IPV6 ADDRESS ARE FF80::/10, WHAT TYPE OF ADDRESS IS IT?

An IPv6 Address Beginning With Ff80::/10 Is A Link-Local Address.

9. WHAT TYPE OF ADDRESS IS 3FFE:204:100:90::1?

This Is A Global Unicast Address, Identified By The First Three Bits Of 001.

10. WHAT IS AN ANYCAST ADDRESS?

An Anycast Address Is An Address That Represents A Service Rather Than A Device, And Can Therefore Appear On More Than One Device.

11. WHAT IS A MULTICAST ADDRESS?

A Multicast Address Is An Address That Represents A Group Of Devices Rather Than A Single Device.

12. WHAT IS THE LENGTH OF THE IPV6 HEADER?

The IPv6 Header Is 40 Bytes In Length.

13. WHAT IS THE PURPOSE OF THE FLOW LABEL FIELD IN THE IPV6 HEADER?

The Flow Label Field, By Labeling Individual Flows (Packets With The Same Source And Destination Address And The Same Source And Destination Ports) In The Header, Is Intended To Allow Highly Granular Load Balancing Without Having To Pay A Performance Penalty From Having To Look Into The Packet Payload.

14. TO WHAT FIELD IN THE IPV4 HEADER DOES THE IPV6 NEXT HEADER FIELD CORRESPOND?

The IPv6 Next Header Field Corresponds To The Ipv4 Protocol Number Field. It Is Named Differently Because The Value Of The Field Might Specify A Following Protocol Header Or It Might Specify An IPv6 Extension Header.

15. TO WHAT FIELD IN THE IPV4 HEADER DOES THE IPV6 HOP LIMIT FIELD CORRESPOND?

The Hop Limit Field Corresponds To The Ipv4 Time To Live (TTL) Field. The Name Is Changed Because Routers Have Never Decremented The Field According To Transit Time; Rather, Every Transit Router Decrements The Field By 1, Marking A Hop Instead Of A Transit Time.

16. IN WHAT WAY IS THE IPV6 NEXT HEADER FIELD LIKE THE IPV4 PROTOCOL NUMBER FIELD, AND IN WHAT WAY IS IT DIFFERENT?

The IPv6 Next Header Field Is Like The IPv4 Protocol Number Field In That It Is An 8-Bit Field That Can, If The Next Header Is An Upper-Layer Protocol Header, Specify The Protocol Number. But It Is Different From The Protocol Number Field In That It Can Also Specify, If The Next Header Is An IPv6 Extension Header, That Header’s Type Number.

17. HOW DO EXTENSION HEADERS MAKE IPV6 PACKETS MORE EFFICIENT?

Extension Headers Make The IPv6 Header More Efficient By Being Specialized To Specific Functions And Only Being Included When The Specific Function Is Used.

18. WHAT IS THE NEXT HEADER VALUE OF ICMPV6?

The Next Header Value Of ICMPv6 (Corresponding To A Protocol Number) Is 58.

19. WHAT IS THE SIGNIFICANT DIFFERENCE BETWEEN IPV4 FRAGMENTATION AND IPV6 FRAGMENTATION?

Aside From The Use Of The Fragment Extension Header, The Significant Difference Of IPv6 Fragmentation From Ipv4 Fragmentation Is That IPv6 Routers Do Not Fragment Packets. It Is Up To The Originating Host To Either Fragment Packets Or Ensure That No Packet It Originates Is Too Large.

20. WHAT ARE THE FIVE ICMPV6 MESSAGES USED BY THE NEIGHBOR DISCOVERY PROTOCOL?

The Five ICMPv6 Messages Used By NDP Are:

Router Solicitation (RS),
Router Advertisement (RA),
Neighbor Solicitation (NS),
Neighbor Advertisement (NA),
And Redirect.

21. WHAT IS THE PURPOSE OF THE M AND O FLAGS IN THE RA?

The M Flag, When Set, Tells Hosts To Use Dhcpv6 To Configure Its Address. The O Flag Tells Hosts To Used Dhcpv6 To Find Other Link Parameters.

22. WHAT IS THE PURPOSE OF THE REACHABLE TIME FIELD OF THE RA?

The Reachable Timer Field Specifies The Time, In Milliseconds, That A Node Should Assume A Neighbor Is Reachable After The Node Has Confirmed Reachability.

23. WHAT IS THE PURPOSE OF THE RETRANSMIT TIMER FIELD IN THE RA?

The Retransmit Timer Field Specifies The Period, In Milliseconds, That A Node Should Wait Between Successive Transmissions Of An NS.

24. WHAT IS INDICATED IF THE ROUTER LIFETIME FIELD IN THE RA IS SET TO 0?

A Router Lifetime Value Of 0 In The Ra Indicates That The Originating Router Should Not Be Added To A Host’s Default Router List.

25. WHAT IS THE PURPOSE AND EFFECT OF THE S FLAG IN THE NA?

The S Flag, When Set, Indicates That The Na Was Sent In Response To An Ns. Two-Way Reachability Is Confirmed, And A Neighbor Address Changed To Reachable State In The Neighbor Cache, Only If The Na Is In Response To A Solicitation; So The Reception Of An Na With The S Bit Cleared, Indicating That It Is Unsolicited, Does Not Change The State Of A Neighbor Cache Entry.

26. WHAT IS THE DIFFERENCE BETWEEN STATEFUL AND STATELESS ADDRESS AUTOCONFIGURATION?

Stateful Address Auto Configuration Relies On DHCPv6 To Allocate An Address To The Host. Stateless Address Auto Configuration Uses RAs To Determine A Prefix Of Larger Scope Than Link-Local, Plus Mac-To-EUI64 Conversion, To Determine A Host’s Address.

27. WHAT TWO STEPS DOES MAC-TO-EUI64 CONVERSION USE TO DERIVE AN INTERFACE ID?

Mac-To-Eui64 Conversion Inserts A Value Of 0xfffe In The Middle Of A Mac Address, Then Flips The U/L Bit To 1, To Create A 64-Bit Interface Id From A 48-Bit Mac Address.

28. WHEN A DEVICE ACQUIRES A UNICAST IPV6 ADDRESS IT MUST PERFORM DUPLICATE ADDRESS DETECTION, WITH ONE EXCEPTION. WHAT IS THAT EXCEPTION?

Duplicate Address Detection Must Never Be Performed On An Anycast Address.

29. WHAT DOES THE PREFIX FF02:0:0:0:0:1:FF00::/104 SIGNIFY?

The Prefix Ff02:0:0:0:0:1:Ff00::/104 Is Used For Solicited Node Multicast Addresses. It Is Prepended To The Last 24 Bits Of An Address That Is Being Solicited.

30. WHAT DOES IPV6 USE IN PLACE OF ARP AND AN ARP CACHE?

IPv6 Uses The NDP Function Neighbor Address Resolution Instead Of ARP, And A Neighbor Cache Instead Of An ARP Cache.

31. WHAT IS A PRIVACY ADDRESS?

A Privacy Address Is One In Which The Interface Id Is Randomly Generated, And Changed Both At Some Regular Period And Whenever A Host Acquires A New Prefix. It Is Used In Conjunction With An Autoconfigured Public Address To Ensure Anonymity Of The Host. The Public Address Is Used For Reachability, But The Private Address Is Used As The Source Address Of Any Packets The Host Originates.

32. WHAT DOES AN INCOMPLETE STATE OF AN ENTRY IN THE NEIGHBOR CACHE SIGNIFY?

An Incomplete State Indicates That Neighbor Address Resolution For The Entry Is In Progress.

33. WHAT DOES A PROBE STATE OF AN ENTRY IN THE NEIGHBOR CACHE SIGNIFY?

A Probe State Indicates That An Ns Has Been Sent To Verify Two-Way Reachability Of A Stale Entry, But A Responding Na Has Not Yet Been Received.

34. WHAT TWO WAYS DOES NEIGHBOR UNREACHABILITY DETECTION USE TO VERIFY TWO-WAY REACHABILITY OF A NEIGHBOR?

Neighbor Unreachability Detection Verifies Two-Way Reachability Of A Neighbor Either By “Hints” From An Upper-Layer Protocol That Has Received An Acknowledgment Of A Sent Message, Or By Actively Probing The Neighbor With An NS.

35. IN PRACTICAL IPV6 APPLICATION, THE ENCAPSULATION OF IPV6 PACKETS INSIDE IPV4 PACKETS IS CALLED WHAT?

Tunneling

Tunneling Provides A Way To Use An Existing Ipv4 Routing Infrastructure To Carry IPv6 Traffic.

Remember, Most Network Is Still Build On IPv4 Structure And IPv4 Is Not Going Away In A Hurry One Of The Many Techniques Used To Migrate To IPv6 Is Tunneling. Tunneling Is A Method That A Network Built On IPv4 Structure Can Be Configured To Traffic IPv6 Packet Simultaneously.

36. INTERNET PROTOCOL VERSION 6 (IPV6) IS THE NEXT-GENERATION INTERNET PROTOCOL VERSION DESIGNATED AS THE SUCCESSOR TO IPV4 BECAUSE IPV4 ADDRESS SPACE IS BEING EXHAUSTED. WHICH ONE OF THE FOLLOWING DESCRIPTIONS ABOUT IPV6 IS CORRECT?

Broadcasts Have Been Eliminated And Replaced With Multicasts.

The IPv6 Multicast Traffic Is Same As That Of IPv4 Broadcast. The Packet Intended To Multiple Hosts Is Sent On A Special IPv6 Multicast Address. Any Host Or Interface That Are Member Of That Multicast Address Will Receive The Multicast Information Or Packet And Process It.

37. WHAT IS THE MULTICAST FOR ALL-ROUTER MULTICAST ACCESS ?

FF02::2

FF02::2 Is An All-Router Multicast Address Access For All Hosts In A Particular Multicast Group.

38. WHICH THREE OF THE FOLLOWING ARE IPV6 TRANSITION MECHANISMS? (CHOOSE THREE)

6TO4 Tunneling
ISATAP Tunneling
TEREDO Tunneling

6TO4 TUNNELS: Just As The Name Suggest; A 6to4 Tunnel Enables IPv6 To Be Tunneled Via IPv4. This Sort Of Tunneling Is Automatically Set Up Using The 2002::/16 IPv6 Address Space.

This Mechanism Allows IPv6 Sites To Communicate With Each Other Over The IPv4 Network Without Explicit Tunnel Setup. The Main Advantage Of This Technology Is That It Requires No End-Node Reconfiguration And Minimal Router Configuration But It Is Not Intended As A Permanent Solution.

INTRA-SITE AUTOMATIC TUNNEL ADDRESSING PROTOCOL (ISATAP) TUNNELS: This Another Type Of Tunnelling Method That When Used, It Enables The Transportation Of IPv6 Traffic Over IPv4; This Type Of ISATAP Method Is Meant For Use Inside A Site And Not Between Two Dual Stacked Edge Devices. The Trafficking Of Packets Between IPv6 Hosts Is Handled Through A Central Ipv6 Enabled Device.

ISATAP Is A Mechanism For Transmitting IPv6 Packets Over IPv4 Network. The Word “Automatic” Means That Once An ISATAP Server/Router Has Been Set Up, Only The Clients Must Be Configured To Connect To It.

TEREDO Tunneling: This Mechanism Tunnels IPv6 Datagrams Within IPv4 UDP Datagrams, Allowing Private Ipv4 Address And Ipv4 NAT Traversal To Be Used.

In Fact, GRE Tunneling Is Also A IPv6 Transition Mechanism But Is Not Mentioned In ROUTE So We Shouldn’t Choose It (There Are 4 Types Of IPv6 Transition Mechanisms Mentioned In ROUTE; They Are: Manual(GRE), 6-To-4, Teredo And ISATAP).

Generic Routing Encapsulation (GRE) IPv6 Tunnels: GRE Is A Cisco Proprietary Protocol That Was Developed For The Purposes Of IPv6 Tunneling. It Operates Very Much The Same As Manual Tunnels.

GRE Is Specially Used To Tunnel Over A Diverse Number Of Network Layer Protocols Other Than IPv4. The GRE Tunnel Can Be Used To Tunnel IPv6 Over IPv4 Vice Versa.

Overlay Tunneling Encapsulates IPv6 Packets In IPv4 Packets For Delivery Across An IPv4 Infrastructure. This Is Similar To How You Create A Generic Routing Encapsulation (GRE) Tunnel To Transport Internetwork Packet Exchange (IPX) Traffic Through An IP Network.

Cisco IOS IPv6 Supports The Following Types Of Overlay Tunneling Mechanisms:

• Manual
• Generic Routing Encapsulation (GRE)
• IPv4-Compatible
• 6to4
• Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)


39. IN THE IPV6 ADDRESS STRUCTURE, HOW MANY BITS ARE INCLUDED IN EACH FIELD?

128

The Format Of Ipv6 Address Looks Like This: 210A:0197:190F:005a:0000:082C:875A:132c.Each Field Separated By The Colon (:) Is 16-Bit Hexadecimal Values, In All; You Have 8 Sets Of 4 Hexadecimal Digits.

40. WHICH TWO OF THESE STATEMENTS ARE TRUE OF IPV6 ADDRESS REPRESENTATION? (CHOOSE TWO)

A Single Interface May Be Assigned Multiple IPV6 Addresses Of Any Type.

Every IPV6 Interface Contains At Least One Loopback Address.

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SUMMARY OF IPV6

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IPv6 Addresses Are Denoted By Eight Groups Of Hexadecimal Quartets Separated By Colons In Between Them.

FOLLOWING IS AN EXAMPLE OF A VALID IPV6 ADDRESS:

2001:cdba:0000:0000:0000:0000:3257:9652

Any Four-Digit Group Of Zeroes Within An IPv6 Address May Be Reduced To A Single Zero Or Altogether Omitted. Therefore, The Following Ipv6 Addresses Are Similar And Equally Valid:

2001:cdba:0000:0000:0000:0000:3257:9652
2001:cdba:0:0:0:0:3257:9652
2001:cdba::3257:9652

THE URL FOR THE ABOVE ADDRESS WILL BE OF THE FORM:

http://[2001:cdba:0000:0000:0000:0000:3257:9652]/

SPECIAL ADDRESSES IN IPV6:

◙   ::/96 The Zero Prefix Denotes Addresses That Are Compatible With The Previously Used Ipv4 Protocol.

◙   ::/128 An Ipv6 Address With All Zeroes In It Is Referred To As An Unspecified Address And Is Used For Addressing Purposes Within A Software.

◙   ::1/128 This Is Called The Loop Back Address And Is Used To Refer To The Local Host. An Application Sending A Packet To This Address Will Get The Packet Back After It Is Looped Back By The IPv6 Stack. The Local Host Address In The IPv4 Was 127.0.0.1.

◙   2001:db8::/32 This Is A Documentation Prefix Allowed In The IPv6. All The Examples Of IPv6 Addresses Should Ideally Use This Prefix To Indicate That It Is An Example.

◙   fec0::/10 This Is A Site-Local Prefix Offered By IPv6. This Address Prefix Signifies That The Address Is Valid Only Within The Local Organization. Subsequently, The Usage Of This Prefix Has Been Discouraged By The RFC.

◙   fc00::/7 This Is Called The Unique Local Address (ULA). These Addresses Are Routed Only Within A Set Of Cooperating Sites. These Were Introduced In The IPv6 To Replace The Site-Local Addresses. These Addresses Also Provide A 40-Bit Pseudorandom Number That Reduces The Risk Of Address Conflicts.

◙   ff00::/8 This Prefix Is Offered By IPv6 To Denote The Multicast Addresses. Any Address Carrying This Prefix Is Automatically Understood To Be A Multicast Address.

◙   fe80::/10 This Is A Link-Local Prefix Offered By IPv6. This Address Prefix Signifies That The Address Is Valid Only In The Local Physical Link.

For More Reference:

◙ - ►  1. What You Need To Know About IPv6:

◙ - ►  2. Important Points To Know About IPv6:

◙ - ►  3. Difference Between IPv4 Vs IPv6:

◙ - ►  4. Deference Between RIPv1 Vs RIPv2 And Vs RIPng:

◙ - ►  5. IPv6 Quick Reference With Questions And Answer:

◙ - ►  6. IPv6 Notes:

◙ - ►  7. IPv6 Command Refernce:

◙ - ►  8. IPv6 Unicast, Multicast And Anycast:

◙ - ►  9. Converting From IPv4 To IPv6:

◙ - ►  10. IPv6 Access Control Lists:

◙ - ►  11. IPv6 AAAA Record:

◙ - ►  12. IPv6 BGP MULTIHOMING:

†

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CONCLUSION:

The Goal Of This Article Is To Give An Easy Way To Understand The “IPv6 Quick Reference Questions With Answer" And Also We Hope This Guide Will Help Every Beginner Who Are Going To Start Cisco Lab Practice Without Any Doubts. Some Topics That You Might Want To Pursue On Your Own That We Did Not Cover In This Article Are Listed Here!

Hands - On Experience Is An Invaluable Part Of Preparing For The Lab Exam And Never Pass Up An Opportunity To Configure Or Troubleshoot A Router ( If You Have Access To Lab Facilities, Take Full Advantage Of Them) There Is No Replacement For The Experience You Can Gain From Working In A Lab, Where You Can Configure Whatever You Want To Configure And Introduce Whatever Problems You Want To Introduce, Without Risk Of Disrupting A Production Network. Thank You And Best Of Luck

This Article Written Author By: Premakumar Thevathasan - CCNA, CCNP, MCSE, MCSA, MCSA - MSG, CIW Security Analyst, CompTIA Certified A+ And Etc.

WARNING AND DISCLAIMER:

This Document Carries No Explicit Or Implied Warranty. Nor Is There Any Guarantee That The Information Contained In This Document Is Accurate. Every Effort Has Been Made To Make All Articles As Complete And As Accurate As Possible, But No Warranty Or Fitness Is Implied.

It Is Offered In The Hopes Of Helping Others, But You Use It At Your Own Risk. The Author Will Not Be Liable For Any Special, Incidental, Consequential Or Indirect Any Damages Due To Loss Of Data Or Any Other Reason That Occur As A Result Of Using This Document. But No Warranty Or Fitness Is Implied. The Information Provided Is On An "As Is" Basic. All Use Is Completely At Your Own Risk.

This Guide Provides Technical Guidance Intended To Help Network Students And Network Administrators Officers Improve The Security Of Their Networks.

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