Ipv6 Ipv4 Tunnel

8/17/2019 Ipv6 Ipv4 Tunnel

1/55

Revision 1.0 (11/30/2006) NMC-COD IPV6 TUNNELING Page 1

© 2006 Copyright NetMasterClass, LLC - All rights reserved.1-888-677-2669 http://www .netmasterclass.com 13530 Dulles Technology Drive, Suite #150, Herndon, VA 20171

This document is a part of “ Public PDF Files” section of NetMasterClass Technical Library: http://www.netmasterclass.com/READiT

NETM ASTERCLASSROUTING AND SWITCHING CCIE® TRACK

NMC-COD

IPv6 Tunneling

Module

N1

R3 R4 N233

1

1

R233

R533

2 244

4

4

4

1

I2

R5 R6R2

R3

R1

N1 R7

I3

I4

I5

FOR

CCIE® C ANDIDATES

IPv6 Class-On-Demand series, that includes Videos, Quizzes and DRILLiT labs, is available: http://www.netmasterclass.com/LEARNiT

http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/http://www.netmasterclass.net/


2/55

Revision: 1.0 (11/30/2006) NMC-COD IPV6 TUNNELING Page 2




DisclaimerNetMasterClass, LLC is an independent training and consulting company based in Herndon, Virginia. Theterms “Cisco”, “Cisco Systems” and “CCIE” are the trademarks of Cisco Systems, Inc. NetMasterClass,LLC is Cisco Learning Partner.

Cisco Non-Disclosure Agreement Compliance

All products and services offered by NetMasterClass, LLC are in full compliance with the Cisco CCIE Labnon-disclosure agreement. The content of the NetMasterClass CCIE preparation materials is based uponthe NetMasterClass “issue spotting and analysis” internetwork training methods.


3/55




NMC-COD: IPv6 Tunneling

Table of Contents

1.1 “Dynamips” configuration files ...........................................................................................................4 1.2 Manual IPv6 Tunnel over IPv4 network.............................................................................................5 1.3 GRE IPv4/IPv6 Tunnel ....................................................................................................................12 1.4 Automatic 6to4 Tunnel.....................................................................................................................25 1.5 IPv4 Compatible IPv6 Tunnel ..........................................................................................................37 1.6 ISATAP Tunnel................................................................................................................................44 1.7 Initial Configuration Scripts..............................................................................................................53

IPv6 block is one of the blocks of Class On Demand IPv6 modules offered byNetMasterClass.



4/55





1.1 “ Dynamips” configuration files

Routers Initial and Final configuration scripts should be stored in the specified folder. The author of thisarticle used “\IPV6\cfg”.

Dynamips/Dynagen network configuration files are listed as following:

IPV4_IPV6_BGP_tunnel_final.netIPV6_6to4_BGP_tunnel_final.netIPV6_6to4_static_route_tunnel_final.netIPV6_GRE_tunnel_4_routers_final.netIPV6_GRE_tunnel_4_routers_init.netIPV6_ISATAP_BGP_tunnel_final.netIPV6_manual_tunnel_4_routers_final.netIPV6_manual_tunnel_4_routers_init.net

If you want to download these files as a zip archive, please use the link below:

http://www.netmasterclass.com/download/IPV6_TUNNELING.zip

Used IOS version:

Cisco IOS Software, 3600 Software (C3640-JK9O3S-M), Version 12.4(5), RELEASE SOFTWARE (fc3)

http://www.netmasterclass.com/download/IPV6_TUNNELING.ziphttp://www.netmasterclass.com/download/IPV6_TUNNELING.zip


5/55




1.2 Manual IPv6 Tunnel over IPv4 network

Characteristics of the manual IPv6 tunnel

• This tunnel is the equivalent to a permanent link between two IPv6 domains over an IPv4backbone

• An IPv6 address is manually configured on a tunnel interface, and manually configured IPv4addresses are assigned to the tunnel source and the tunnel destination

• The host or router at each end of a configured tunnel must support both the IPv4 and IPv6protocol stacks (dual stack)

• Manually configured tunnels can be configured between border routers or between a border routerand a host

The primary use is for stable connections that require regular secure communication between two edgerouters. You can also use this technique between an end system and an edge router, or for connection toremote IPv6 networks.

Manual tunnels are similar to GRE based tunnels.



6/55





Manual Tunnel Configuration:

Dynamips/Dynagen Topology files:IPV6_manual_tunnel_4_routers_init.net, IPV6_manual_tunnel_4_routers_final.net

1. Initialize R1, R2, R3 and R4 with the initial configuration scripts. Scripts are in Appendix A.

2. Create a manual tunnel between R1 and R2 using the loopback interfaces 101 and 102. R1 and R2run RIP to provide IPv4 connectivity between Lo101 and Lo102:

Verify connectivity between Lo101 and Lo102 involved in the tunnel source and destination:

R1#ping 172.16.102.1 source 172.16.101.1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 172. 16. 102. 1, t i meout i s 2 seconds:Packet sent wi t h a sour ce addr ess of 172. 16. 101. 1! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 12/ 38/ 56 ms

Configure the tunnel on R1 and R2:

R1#conf tR1( conf i g) #i nt erf ace Tunnel 12R1( conf i g- i f ) # no i p addr essR1( conf i g- i f ) # i pv6 addr ess 12: : 12: 1/ 64R1( conf i g- i f ) # t unnel sour ce 172. 16. 101. 1R1( conf i g- i f ) # t unnel dest i nat i on 172. 16. 102. 1R1( conf i g- i f ) # t unnel mode i pv6i p

R2#conf tR2( conf i g) #i nt erf ace Tunnel 12R2( conf i g- i f ) # no i p addr essR2( conf i g- i f ) # i pv6 addr ess 12: : 12: 2/ 64R2( conf i g- i f ) # t unnel sour ce 172. 16. 102. 1R2( conf i g- i f ) # t unnel dest i nat i on 172. 16. 101. 1R2( conf i g- i f ) # t unnel mode i pv6i p

Run debug tunnel and ping tunnel end point IPv6 address, for example from R2:

R2#debug tunnel

Tunnel I nt er f ace debuggi ng i s onR2#R2#ping 12::12:1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 12: : 12: 1, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 20/ 82/ 136 msR2#*Mar 1 00: 06: 32. 215: Tunnel 12: I Pv6/ I P encapsul ated 172. 16. 102. 1- >172. 16. 101. 1( l i nkt ype=79, l en=120)


7/55




*Mar 1 00: 06: 32. 339: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 101. 1- >172. 16. 102. 1 (l en=120t t l =254 t os=0x0)

*Mar 1 00: 06: 32. 343: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 101. 1- >172. 16. 102. 1( l en=120, t t l =254)*Mar 1 00: 06: 32. 347: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 00: 06: 32. 347: 12: : 12: 1 - > 12: : 12: 2 ( l en=60 t t l =64)*Mar 1 00: 06: 32. 359: Tunnel 12: I Pv6/ I P encapsul ated 172. 16. 102. 1- >172. 16. 101. 1( l i nkt ype=79, l en=120)*Mar 1 00: 06: 32. 451: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 101. 1- >172. 16. 102. 1 (l en=120t t l =254 t os=0x0)*Mar 1 00: 06: 32. 455: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 101. 1- >172. 16. 102. 1( l en=120, t t l =254)*Mar 1 00: 06: 32. 459: Tunnel 12: decapsul ated I Pv6/ I P packet……R2#u al lAl l possi bl e debuggi ng has been t ur ned of fR2#

Note: you can see the tunnel source and destination IPv4 addresses (172.16.101.1 and 172.16.102.1)involved in encapsulation/decapsulation.

Question: What IPv4 protocol is used to carry the encapsulated IPv6 packets?

Answer: It is IPv4 protocol number 41 which is according to IANA’s PROTOCOL NUMBERS athttp://www.iana.org/assignments/protocol-numbers :

Deci mal Keyword Prot ocol Ref erences- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

41 I Pv6 I pv6 [ Deer i ng]

You can see this number in the output of debug ip packet detail while pinging the tunnel IPv6 endpoints:

R1#deb ip pack det

I P packet debuggi ng i s on ( detai l ed)

R1#pi ng 12: : 12: 2

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 12: : 12: 2, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 16/ 63/ 96 msR1#*Mar 1 00: 10: 46. 115: I P: s=172. 16. 101. 1 ( Tunnel 12) , d=172. 16. 102. 1 ( Ser i al 1/ 0), l en 120,

sendi ng, prot o=41*Mar 1 00: 10: 46. 203: I P: t abl ei d=0, s=172. 16. 102. 1 ( Ser i al 1/ 0), d=172. 16. 101. 1( Loopback101) , r out ed vi a RI B….

Here are some important properties of the tunnel interface:


http://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbers


8/55





R1#show interfaces tunnel 12

Tunnel 12 i s up, l i ne prot ocol i s up

Hardware i s TunnelMTU 1514 byt es, BW 9 Kbi t , DLY 500000 usec,rel i abi l i t y 255/ 255, t xl oad 1/ 255, rxl oad 1/ 255

Encapsul ati on TUNNEL, l oopback not setKeepal i ve not set

Tunnel sour ce 172. 16. 101. 1, dest i nat i on 172. 16. 102. 1 Tunnel pr ot ocol / t r anspor t I Pv6/ I P Tunnel TTL 255Fast t unnel i ng enabl ed

Tunnel t r ansmi t bandwi dt h 8000 ( kbps) Tunnel r ecei ve bandwi dt h 8000 ( kbps)Last i nput 00: 09: 41, out put 00: 09: 41, out put hang neverLast cl ear i ng of " show i nt erf ace" counter s neverI nput queue: 0/ 75/ 0/ 0 (si ze/ max/ dr ops/ f l ushes) ; Tot al out put dr ops: 0Queuei ng str ategy: f i f oOutput queue: 0/ 0 (s i ze/ max)5 mi nut e i nput r ate 0 bi t s/ sec, 0 packet s/ sec

5 mi nut e output r ate 0 bi t s/ sec, 0 packets/ sec22 packets i nput, 2624 byt es, 0 no buf f erRecei ved 0 br oadcast s, 0 runt s, 0 gi ant s, 0 thrott l es0 i nput err ors, 0 CRC, 0 f r ame, 0 over r un, 0 i gnored, 0 abort22 packets out put , 2184 byt es, 0 underr uns0 out put err ors, 0 col l i s i ons, 0 i nt er f ace reset s0 out put buf f er f ai l ures, 0 out put buf f ers swapped out

R1#

Look at the IPv6 addresses assigned to the tunnel interface. The tunnel link local address will be formedfrom the IPv4 address of the tunnel source. On R1, the tunnel source is 172.16.101.1, therefore:

Deci mal 172 = Hex ACDeci mal 16 = Hex 10Deci mal 101 = Hex 65Deci mal 1 = Hex 1

172. 16. 101. 1 - > AC10: 6501

R1#show ipv6 int tunnel 12

Tunnel 12 i s up, l i ne prot ocol i s upI Pv6 i s enabl ed, l i nk- l ocal addr ess i s FE80: : AC10: 6501Gl obal uni cast addr ess( es) :

12: : 12: 1, subnet i s 12: : / 64 J oi ned gr oup address ( es) :

FF02: : 1FF02: : 2FF02: : 1: FF10: 6501FF02: : 1: FF12: 1

MTU i s 1480 byt esI CMP er r or messages l i mi t ed t o one every 100 mi l l i secondsI CMP r edi r ect s are enabl ed

ND DAD i s enabl ed, number of DAD at t empt s: 1ND r eachabl e t i me i s 30000 mi l l i seconds

R1#

Likewise on R2 the tunnel source 172.16.102.1 will be translated to AC10:6601

Just like with the serial IPv6 interface, when you assign Global unicast IPv6 address on the tunnelinterface, the IOS will create two entries in the IPv6 routing table, one Local entry with the /128 mask


9/55




pointing to the tunnel interface and the other is the connected prefix with the mask matching what wasspecified on the tunnel interface. In our case this is /64.

R1#show ipv6 route

I Pv6 Rout i ng Tabl e - 6 ent r i esCodes: C - Connect ed, L - Local , S - St ati c, R - RI P, B - BGP

U - Per- user St at i c rout eI 1 - I SI S L1, I 2 - I SI S L2, I A - I SI S i nt erarea, I S - I SI S summaryO - OSPF i ntr a, OI - OSPF i nter , OE1 - OSPF ext 1, OE2 - OSPF ext 2ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

C 12: : / 64 [ 0/ 0]vi a : : , Tunnel 12

L 12: : 12: 1/ 128 [ 0/ 0]vi a : : , Tunnel 12

C 13: : / 64 [ 0/ 0]vi a : : , Ser i al 1/ 1

L 13: : 13: 1/ 128 [ 0/ 0]vi a : : , Ser i al 1/ 1

L FE80: : / 10 [ 0/ 0]vi a : : , Nul l 0L FF00: : / 8 [ 0/ 0]

vi a : : , Nul l 0R1#

Routing protocols over a manual IPv6 tunnel

The tunnel is considered by IOS as an IPv6 link, just like an IPv6 serial interface. You can run allsupported IPv6 routing protocols over the IPv6 manual tunnel. Here is an example of an IPv6 RIPconfiguration:



10/55





Configure IPv6 RIP instance “RIPoTU” on R1, R2, R3 and R4 and enable it on the respective interfaces,look at the diagram:

R1#conf tR1( conf i g) #i pv6 uni cast - r out i ngR1( conf i g) #i pv6 r out er r i p RI PoTUR1( conf i g- r t r ) #i nt t u 12R1( conf i g- i f ) #i pv6 r i p RI PoTU enabl eR1( conf i g- i f ) #i nt s1/ 1R1( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

R2#conf tR2( conf i g) #i pv6 uni cast - r out i ngR2( conf i g) #i pv6 r out er r i p RI PoTUR2( conf i g- r t r ) #i nt t u12R2( conf i g- i f ) #i pv6 r i p RI PoTU enabl eR2( conf i g- i f ) #i nt s1/ 1

R2( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

R3#conf tR3( conf i g) #i pv6 uni cast - r out i ngR3( conf i g) #i pv6 r out er r i p RI PoTUR3( conf i g- r t r ) #i nt s1/ 0R3( conf i g- i f ) #i pv6 r out er r i p RI PoTU

R4#conf tR4( conf i g) #i pv6 uni cast - r out i ngR4( conf i g) #i pv6 r out er r i p RI PoTUR4( conf i g- r t r ) #i nt s1/ 0R4( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

On R1 check the RIP prefixes learned via the Tunnel12 interface:

R1#show ipv6 route rip



R 24: : / 64 [ 120/ 2]vi a FE80: : AC10: 6601, Tunnel 12

R1#

Check the routing table on the other routers:




R 13: : / 64 [ 120/ 2]vi a FE80: : AC10: 6501, Tunnel 12

R2#


11/55






I Pv6 Rout i ng Tabl e - 6 ent r i es

Codes: C - Connect ed, L - Local , S - St ati c, R - RI P, B - BGPU - Per- user St at i c rout eI 1 - I SI S L1, I 2 - I SI S L2, I A - I SI S i nt erarea, I S - I SI S summaryO - OSPF i ntr a, OI - OSPF i nter , OE1 - OSPF ext 1, OE2 - OSPF ext 2ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

R 12: : / 64 [ 120/ 2]vi a FE80: : CE00: 5FF: FE68: 0, Ser i al 1/ 0

R 24: : / 64 [ 120/ 3]vi a FE80: : CE00: 5FF: FE68: 0, Ser i al 1/ 0

R3#

Now you can ping between the farthest IPv6 addresses on R3 and R4. Your traffic will be routed via theTunnel 12 between R1 and R2

R3#ping 24::24:4

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 24: : 24: 4, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 24/ 97/ 188 msR3#


12/55


13/55




GRE IPv4 Tunnel Configuration:

Dynamips/Dynagen Topology files:IPV6_GRE_tunnel_4_routers_init.net, IPV6_GRE_tunnel_4_routers_final.net

IPv6 is a passenger protocol.IPv4 is a transport protocol.

Initialize R1, R2, R3 and R4 with the initial configuration scripts.

Create a IPv6 GRE tunnel between R1 and R2 using the loopback interfaces 101 and 102. R1 and R2 run

RIP to provide IPv4 connectivity between Lo101 and Lo102:

Verify connectivity between Lo101 and Lo102 involved in tunnel source and destination:

R1#ping 172.16.102.1 source 172.16.101.1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 172. 16. 102. 1, t i meout i s 2 seconds:Packet sent wi t h a sour ce addr ess of 172. 16. 101. 1! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 12/ 38/ 56 ms

Configure tunnel on R1 and R2:

R1#conf tR1(conf i g) #i nter f ace Tunnel 12R1( conf i g- i f ) # no i p addressR1( conf i g- i f ) # i pv6 addr ess 12: : 12: 1/ 64R1( conf i g- i f ) # t unnel sour ce 172. 16. 101. 1R1( conf i g- i f ) # t unnel desti nat i on 172. 16. 102. 1

R2#conf tR2(conf i g) #i nter f ace Tunnel 12R2( conf i g- i f ) # no i p addressR2( conf i g- i f ) # i pv6 addr ess 12: : 12: 2/ 64R2( conf i g- i f ) # t unnel sour ce 172. 16. 102. 1R2( conf i g- i f ) # t unnel desti nat i on 172. 16. 101. 1

You do not have to configure GRE mode on the tunnel, it is the default on a Cisco router.

Run debug tunnel and ping tunnel end point IPv6 address, for example from R2:

R2#deb tunnel

Tunnel I nt er f ace debuggi ng i s on



14/55




R2#ping 12::12:1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 12: : 12: 1, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 20/ 82/ 136 msR2#*Mar 1 00: 08: 06. 775: Tunnel 12: GRE/ I P encapsul ated 172. 16. 102. 1- >172. 16. 101. 1( l i nkt ype=79, l en=124)*Mar 1 00: 08: 06. 843: Tunnel 12: GRE/ I P t o cl assi f y 172. 16. 101. 1->172. 16. 102. 1 ( l en=124t ype=0x86DD t t l =254 t os=0x0)*Mar 1 00: 08: 06. 851: Tunnel 12: GRE/ I P encapsul ated 172. 16. 102. 1- >172. 16. 101. 1( l i nkt ype=79, l en=124)*Mar 1 00: 08: 06. 943: Tunnel 12: GRE/ I P t o cl assi f y 172. 16. 101. 1->172. 16. 102. 1 ( l en=124t ype=0x86DD t t l =254 t os=0x0)*Mar 1 00: 08: 06. 951: Tunnel 12: GRE/ I P encapsul ated 172. 16. 102. 1- >172. 16. 101. 1( l i nkt ype=79, l en=124)*Mar 1 00: 08: 06. 959: Tunnel 12: GRE/ I P t o cl assi f y 172. 16. 101. 1->172. 16. 102. 1 ( l en=124t ype=0x86DD t t l =254 t os=0x0)

You can see the tunnel source and destination IPv4 addresses (172.16.101.1 and 172.16.102.1)involved in encapsulation/decapsulation. Type 0x86DD is the Ethernet protocol type for IPv6. It is apayload of the GRE packet from R1.

Question: What IPv4 protocol is used to carry the encapsulated IPv6 packets?

Answer: It is IPv4 protocol number 41 which is according to IANA’s PROTOCOL NUMBERS athttp://www.iana.org/assignments/protocol-numbers :

Deci mal Keyword Prot ocol Ref erences- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -47 GRE General Rout i ng Encapsul at i on [ Tony Li ]

You can see this number in the output of debug ip packet detail while pinging the tunnel IPv6 endpoints:

R2#deb ip pack detail

I P packet debuggi ng i s on ( detai l ed)R2#pi ng 12: : 12: 1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 12: : 12: 1, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 20/ 72/ 124 msR2#*Mar 1 00: 14: 42. 043: I P: s=172. 16. 102. 1 ( Tunnel 12) , d=172. 16. 101. 1 ( Ser i al 1/ 0), l en 124,sendi ng, prot o=47*Mar 1 00: 14: 42. 179: I P: s=172. 16. 102. 1 ( Tunnel 12) , d=172. 16. 101. 1 ( Ser i al 1/ 0), l en 124,sendi ng, prot o=47….


http://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbers


15/55





Here are some important properties of tunnel interface:

R2#show interfaces tunnel 12 Tunnel 12 i s up, l i ne prot ocol i s up

Hardware i s TunnelMTU 1514 byt es, BW 9 Kbi t , DLY 500000 usec,

rel i abi l i t y 255/ 255, t xl oad 1/ 255, rxl oad 1/ 255Encapsul ati on TUNNEL, l oopback not setKeepal i ve not set

Tunnel sour ce 172. 16. 102. 1, dest i nat i on 172. 16. 101. 1 Tunnel pr ot ocol / t r anspor t GRE/ I P

Key di sabl ed, sequenci ng di sabl edChecksummi ng of packet s di sabl ed

Tunnel TTL 255Fast t unnel i ng enabl ed

Tunnel t r ansmi t bandwi dt h 8000 ( kbps) Tunnel r ecei ve bandwi dt h 8000 ( kbps)Last i nput 00: 00: 49, out put 00: 00: 49, out put hang neverLast cl ear i ng of " show i nt erf ace" counter s never

I nput queue: 0/ 75/ 0/ 0 (si ze/ max/ dr ops/ f l ushes) ; Tot al out put dr ops: 0Queuei ng str ategy: f i f oOutput queue: 0/ 0 (s i ze/ max)5 mi nut e i nput r ate 0 bi t s/ sec, 0 packet s/ sec5 mi nut e output r ate 0 bi t s/ sec, 0 packets/ sec

10 packets i nput, 1240 byt es, 0 no buf f erRecei ved 0 br oadcast s, 0 runt s, 0 gi ant s, 0 thrott l es0 i nput err ors, 0 CRC, 0 f r ame, 0 over r un, 0 i gnored, 0 abort27 packets out put , 2892 byt es, 0 underr uns0 out put err ors, 0 col l i s i ons, 0 i nt er f ace reset s0 out put buf f er f ai l ures, 0 out put buf f ers swapped out

R2#

Look at the IPv6 addresses assigned to the tunnel interface of R1 or R2. The tunnel link local address willbe formed just like any other MAC-less interfaces (loopback, Serial, etc) based on a MAC address of thefirst Ethernet interface. For more details listen to IPv6 address assignment module.

You can override the local link address with a manually configured one.

R1#show ipv6 interface tunnel 12

Tunnel 12 i s up, l i ne prot ocol i s upI Pv6 i s enabl ed, l i nk- l ocal addr ess i s FE80: : CE00: CFF: FE58: 0Gl obal uni cast addr ess( es) :


FF02: : 1FF02: : 2FF02: : 1: FF12: 1FF02: : 1: FF58: 0

MTU i s 1476 byt esI CMP er r or messages l i mi t ed t o one every 100 mi l l i secondsI CMP r edi r ect s are enabl ed

ND DAD i s enabl ed, number of DAD at t empt s: 1ND r eachabl e t i me i s 30000 mi l l i seconds

R1#

Just like with the serial IPv6 interface, when you assign Global unicast IPv6 address on the tunnelinterface, the IOS will create two entries in the IPv6 routing table, one Local entry with the /128 maskpointing to tunnel interface and the other is a Connected prefix with the mask matching what was specified


16/55




on the tunnel interface. In this case it was /64. These forwarding entries are no different from thosecreated by manual IPv6 tunnel. Please see the manual tunnel configuration section.

R1#show ipv6 route



C 12: : / 64 [ 0/ 0]vi a : : , Tunnel 12

L 12: : 12: 1/ 128 [ 0/ 0]vi a : : , Tunnel 12

C 13: : / 64 [ 0/ 0]vi a : : , Ser i al 1/ 1

L 13: : 13: 1/ 128 [ 0/ 0]vi a : : , Ser i al 1/ 1

L FE80: : / 10 [ 0/ 0]vi a : : , Nul l 0L FF00: : / 8 [ 0/ 0]

vi a : : , Nul l 0R1#

Routing protocols over GRE IPv4 tunnel

Tunnel is considered by IOS as an IPv6 link, just like an IPv6 serial interface. You can run all supportedIPv6 routing protocols over the IPv6 manual tunnel. Here is an example of IPv6 RIP configuration:



17/55




Configure IPv6 RIP instance “RIPoTU” on R1, R2, R3 and R4 and enable it on the respective interfaces,look at the diagram:

R1#conf tR1( conf i g) #i pv6 uni cast - r out i ngR1(conf i g) #i pv6 rout er r i p RI PoTUR1( conf i g- rt r ) #i nt t u 12R1( conf i g- i f ) #i pv6 ri p RI PoTU enabl eR1( conf i g- i f ) #i nt s1/ 1R1( conf i g- i f ) #i pv6 ri p RI PoTU enabl e

R2#conf tR2( conf i g) #i pv6 uni cast - r out i ngR2(conf i g) #i pv6 rout er r i p RI PoTUR2( conf i g- rt r ) #i nt t u12R2( conf i g- i f ) #i pv6 ri p RI PoTU enabl eR2( conf i g- i f ) #i nt s1/ 1R2( conf i g- i f ) #i pv6 ri p RI PoTU enabl e

R3#conf tR3( conf i g) #i pv6 uni cast - r out i ngR3(conf i g) #i pv6 rout er r i p RI PoTUR3( conf i g- rt r ) #i nt s1/ 0R3( conf i g- i f ) #i pv6 ri p RI PoTU enabl e

R4#conf tR4( conf i g) #i pv6 uni cast - r out i ngR4(conf i g) #i pv6 rout er r i p RI PoTUR4( conf i g- rt r ) #i nt s1/ 0R4( conf i g- i f ) #i pv6 ri p RI PoTU enabl e

On R1 check the RIP prefixes learned via Tunnel12 interface:


I Pv6 Rout i ng Tabl e - 7 ent r i esCodes: C - Connect ed, L - Local , S - St ati c, R - RI P, B - BGPU - Per- user St at i c rout eI 1 - I SI S L1, I 2 - I SI S L2, I A - I SI S i nt erarea, I S - I SI S summaryO - OSPF i ntr a, OI - OSPF i nter , OE1 - OSPF ext 1, OE2 - OSPF ext 2ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

R 24: : / 64 [ 120/ 2]vi a FE80: : CE01: CFF: FE58: 0, Tunnel 12

R1#

The next hop learned via IPv6 IGPs is always link local.

Check the routing table on the other routers:





R2#



18/55







R 12: : / 64 [ 120/ 2]vi a FE80: : CE00: CFF: FE58: 0, Seri al 1/ 0


R3#

Now you can ping between the farthest IPv6 addresses on R3 and R4. Your traffic will be routed via theTunnel 12 between R1 and R2.

R3#ping 24::24:4


GRE IPv6 Tunnel Configuration

IPv6 is a passenger protocol.IPv6 is a transport protocol.

GRE tunnel can be built with the IPv6 used as a transport protocol. For example create tunnel betweenIPv6 only sites for VPN or other purposes. Next example illustrates it with the use of IPv6 OSPF betweenIPv6 only routers R3 and R4. Use the configuration from the previous example for GRE IPv4 configuration.

Configure tunnel between R3 and R4 using the IPv6 addresses assigned to S1/0 interfaces for the tunnelsource and destination. Also GRE mode is going to be IPv6. Form IPv6 OSPF adjacency over the tunneland advertise networks 33::/64 and 44/64 between R3 and R4.


19/55




Make sure you can ping between these networks.R1 and R2 are not aware about OSPF networks.

R3#conf tR3(conf i g) #i nter f ace t unnel 34*Mar 1 01: 52: 54. 071: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o downR3( conf i g- i f ) #i pv6 addr ess 34: : 34: 3/ 24R3( conf i g- i f ) #t unnel sour ce 13: : 13: 3R3( conf i g- i f ) #t unnel dest 24: : 24: 4R3(conf i g- i f ) #t unnel mode gr e i pv6R3(conf i g- i f )#*Mar 1 01: 54: 03. 167: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o upR3(conf i g- i f )#

R4#conf tR4(conf i g) #i nter f ace t unnel 34*Mar 1 01: 54: 46. 039: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o downR4( conf i g- i f ) #i pv6 addr ess 34: : 34: 4/ 64R4( conf i g- i f ) #t unnel sour ce 24: : 24: 4R4( conf i g- i f ) #t unnel dest i nat i on 13: : 13: 3R4(conf i g- i f ) #t unnel mode gr e i pv6R4(conf i g- i f )#*Mar 1 01: 55: 54. 559: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o upR4(conf i g- i f )#



20/55





Verify connectivity between end points of the GRE IPv6 tunnel:

R3#ping 34::34:4

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 34: : 34: 4, t i meout i s 2 seconds:! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 48/ 110/ 204 msR3#

Configure tunnel interfaces on R3 and R4:

R3#conf tEnt er conf i gur at i on commands, one per l i ne. End wi t h CNTL/ Z.R3(conf i g) #i nter f ace t unnel 34*Mar 1 01: 52: 54. 071: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o down

R3( conf i g- i f ) #i pv6 addr ess 34: : 34: 3/ 24R3( conf i g- i f ) #t unnel sour ce 13: : 13: 3R3( conf i g- i f ) #t unnel dest 24: : 24: 4R3(conf i g- i f ) #t unnel mode gr e i pv6R3(conf i g- i f )#*Mar 1 01: 54: 03. 167: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o upR3(conf i g- i f )# R4(conf i g) #i nter f ace t unnel 34*Mar 1 01: 54: 46. 039: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o downR4( conf i g- i f ) #i pv6 addr ess 34: : 34: 4/ 64R4( conf i g- i f ) #t unnel sour ce 24: : 24: 4R4( conf i g- i f ) #t unnel dest i nat i on 13: : 13: 3R4(conf i g- i f ) #t unnel mode gr e i pv6R4(conf i g- i f )#

*Mar 1 01: 55: 54. 559: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Tunnel 34, changedst ate t o upR4(conf i g- i f )#

R3#show interfaces tunnel 34

Tunnel 34 i s up, l i ne prot ocol i s upHardware i s TunnelMTU 1514 byt es, BW 9 Kbi t , DLY 500000 usec,


Tunnel sour ce 13: : 13: 3, dest i nat i on 24: : 24: 4 Tunnel pr ot ocol / t r anspor t GRE/ I Pv6

Key di sabl ed, sequenci ng di sabl edChecksummi ng of packet s di sabl ed

Tunnel TTL 255

Tunnel t r ansmi t bandwi dt h 8000 ( kbps) Tunnel r ecei ve bandwi dt h 8000 ( kbps)Last i nput 00: 00: 08, out put 00: 00: 09, out put hang neverLast cl ear i ng of " show i nt erf ace" counter s neverI nput queue: 0/ 75/ 0/ 0 (si ze/ max/ dr ops/ f l ushes) ; Tot al out put dr ops: 0Queuei ng str ategy: f i f oOutput queue: 0/ 0 (s i ze/ max)5 mi nut e i nput r ate 0 bi t s/ sec, 0 packet s/ sec5 mi nut e output r ate 0 bi t s/ sec, 0 packets/ sec

181 packets i nput, 22704 byt es, 0 no buf f erRecei ved 0 br oadcast s, 0 runt s, 0 gi ant s, 0 thrott l es


21/55





0 i nput err ors, 0 CRC, 0 f r ame, 0 over r un, 0 i gnored, 0 abort190 packet s out put , 23752 bytes, 0 under r uns

0 out put err ors, 0 col l i s i ons, 0 i nt er f ace reset s0 out put buf f er f ai l ures, 0 out put buf f ers swapped outR3#

Note: Transport protocol is IPv6 in the output above.

R3#show ipv6 interface tunnel 34

Tunnel 34 i s up, l i ne prot ocol i s upI Pv6 i s enabl ed, l i nk- l ocal addr ess i s FE80: : CE02: DFF: FE7C: 0Gl obal uni cast addr ess( es) :


FF02: : 1FF02: : 2FF02: : 5FF02: : 1: FF34: 3FF02: : 1: FF7C: 0

MTU i s 1456 byt esI CMP er r or messages l i mi t ed t o one every 100 mi l l i secondsI CMP r edi r ect s are enabl edND DAD i s enabl ed, number of DAD at t empt s: 1ND r eachabl e t i me i s 30000 mi l l i secondsHosts use st atel ess aut oconfi g f or addresses.

R3#

Verify connectivity between the end points:

R3#ping 34::34:4

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 34: : 34: 4, t i meout i s 2 seconds:! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 48/ 110/ 204 ms

R3#

Configure IPv6 OSPF between R3 and R4 according to diagram:

R3#conf tEnt er conf i gur at i on commands, one per l i ne. End wi t h CNTL/ Z.R3(conf i g) #i nt t u34R3(conf i g- i f ) #i pv6 ospf 1 area 0R3( conf i g- i f ) #i nt l o 33R3( conf i g- i f ) #i pv6*Mar 1 01: 58: 54. 783: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Loopback33, changedst ate t o upR3( conf i g- i f ) #i pv6 addr ess 33: : 33: 1/ 64R3(conf i g- i f ) #i pv6 ospf 1 area 33R3(conf i g- i f )#*Mar 1 02: 00: 15. 331: %OSPFv3- 5- ADJ CHG: Process 1, Nbr 172. 16. 24. 4 on Tunnel 34 f r om

LOADI NG t o FULL, Loadi ng DoneR3(conf i g- i f )# R4( conf i g- i f ) #i nt t u 34R4(conf i g- i f ) #i pv6 ospf 1 area 0R4( conf i g- i f ) #i nt l o 44R4(conf i g- i f )#*Mar 1 02: 00: 14. 715: %LI NEPROTO- 5- UPDOWN: Li ne prot ocol on I nter f ace Loopback44, changedst ate t o up*Mar 1 02: 00: 19. 679: %OSPFv3- 5- ADJ CHG: Process 1, Nbr 172. 16. 13. 3 on Tunnel 34 f r omLOADI NG t o FULL, Loadi ng Done


22/55





R4( conf i g- i f ) #i pv6 addr ess 44: : 44: 1/ 64R4(conf i g- i f ) #i pv6 ospf 1 area 44

R4(conf i g- i f )#

R3#show ipv6 ospf nei

Nei ghbor I D Pri St ate Dead Ti me I nt erf ace I D I nt erf ace172. 16. 24. 4 1 FULL/ - 00: 00: 38 12 Tunnel 34R3#show i pv6 r oute ospfI Pv6 Rout i ng Tabl e - 12 ent r i esCodes: C - Connect ed, L - Local , S - St ati c, R - RI P, B - BGP


O 34: : / 64 [ 110/ 22222]vi a FE80: : CE03: DFF: FE7C: 0, Tunnel 34

OI 44: : 44: 1/ 128 [ 110/ 11111]

vi a FE80: : CE03: DFF: FE7C: 0, Tunnel 34R3#

Verify connectivity

R3#ping 44::44:1 source 33::33:1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 44: : 44: 1, t i meout i s 2 seconds:Packet sent wi t h a source address of 33: : 33: 1! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 88/ 136/ 196 msR3#

Encapsulation/decapsulation and forwarding steps when ping 44::44:1 source 33::33:1

1. R3 builds an ICMP packet with the source 33:33:1 and destination 44::44:1 and does thelookup in ipv6 routing tables to find the outgoing interface. Here is an entry in the routingtable:

R3#show ipv6 route 44::44:1



OI 44: : 44: 1/ 128 [ 110/ 11111]vi a FE80: : CE03: DFF: FE7C: 0, Tunnel 34

R3#

2. The outgoing interface is Tunnel34 meaning that R3 needs to build an IPv6 GRE packet viaencapsulation (debug tunnel):

*Mar 1 02: 36: 42. 539: Tunnel 34: GRE/ I Pv6 encapsul ated 13: : 13: 3- >24: : 24: 4 ( l i nkt ype=79,l en=144)

3. Now R3 is going to do the lookup for 24::24:4 which is the destination of the IPv6 GREpacket:


23/55









R3#

4. R3 finds that the outgo ing interface is S1/0, encapsulates the GRE IPv6 packet in HDLC(default cisco serial encapsulation) and forward to R1.

5. R1 does a lookup in the routing table for 24::24:4 and finds entry:





R1#

6. Outgoing interface Tunnel12 tells router that the IPv6 GRE packet needs to be

encapsulated in GRE IPV4 packet with the following source and destination IPv4addresses:

*Mar 1 00: 08: 06. 775: Tunnel 12: GRE/ I P encapsul ated 172. 16. 101. 1- >172. 16. 102. 1( l i nkt ype=79, l en=124)

7. R1 does a lookup for 172.16.102.1

R1#show ip route 172.16.102.1

Rout i ng entr y f or 172. 16. 102. 0/ 24Known vi a "r i p", di st ance 120, metr i c 1Redi str i but i ng vi a r i pLast updat e f r om172. 16. 12. 2 on Ser i al 1/ 0, 00: 00: 16 agoRout i ng Descri pt or Bl ocks:* 172. 16. 12. 2, f r om 172. 16. 12. 2, 00: 00: 16 ago, vi a Ser i al 1/ 0

Rout e met r i c i s 1, t r af f i c shar e count i s 1R1#

8. R1 finds Serial1/0 as an outgoing interface, encapsulates GRE IPv4 packet in HDLC and

forward to R2.

9. R2 receives GRE IPv4 packet and decapsulates it:

Mar 1 02: 49: 26. 823: Tunnel 12: GRE/ I P t o cl assi f y 172. 16. 101. 1- >172. 16. 102. 1 ( l en=124t ype=0x86DD t t l =254 t os=0x0)

10. Note the type of payload i s the IPv6 packet. The decapsulated IPv6 packet is the GRE IPv6packet with the source and destination 13::13:3->24::24:4

11. R2 does the lookup for 24::24:4 in the table:


24/55








C 24: : / 64 [ 0/ 0]vi a : : , Ser i al 1/ 1

12. Finds the outgoing interface Serail1/1, encapsulates in HDLC and forwards to R4.

13. R4 receives the GRE IPv6 packet and decapsulates i t:

*Mar 1 02: 54: 39. 379: Tunnel 34: GRE/ I Pv6 t o decaps 13: : 13: 3- >24: : 24: 4 ( l en=84 t t l =62)*Mar 1 02: 54: 39. 379: Tunnel 34: GRE decapsul ated I Pv6 packet ( l i nkt ype=79, l en=80)

14. R4 receives the ICMP echo request and replies:

R4#*Mar 1 02: 58: 54. 455: I CMPv6: Recei ved I CMPv6 packet f r om 33: : 33: 1, t ype 128*Mar 1 02: 58: 54. 459: I CMPv6: Recei ved echo r equest f r om 33: : 33: 1*Mar 1 02: 58: 54. 463: I CMPv6: Sendi ng echo r epl y t o 33: : 33: 1

15. Same steps will be involved to process the ICMP reply and deliver it to R3.


25/55





1.4 Automatic 6to4 Tunnel

Characteristics of the automatic 6to4 tunnel

• Allows isolated IPv6 domains to be connected over an IPv4 network to remote IPv6 networks.

• The tunnel is not point-to-point; it is point-to-multipoint.

• The IPv4 address embedded in the IPv6 address is used to find the other end of the automatictunnel.

• The IANA has permanently assigned one 13-bit IPv6 Top Level Aggregator (TLA) for the 6to4scheme. Its numeric value is 0x0002, i.e., it is 2002::/16 when expressed as an IPv6 addressprefix. It is a recommended prefix for the real life deployments. In the lab you can use any prefix toset up the 6to4 tunnel.

The benefits to the enterprise of using 6to4 tunnels are as follows:

• Cisco IOS software supports 6to4 tunnels.

• The end-user host configuration is simple—it requires minimal management overhead.

• The tunnel is automatic; no enterprise-specific configuration is required at the 6to4 relay site. 6to4tunnels scale well.

• This solution accommodates dynamic IP addresses at the enterprise.

• The tunnel exists only for the duration of the session.

• A 6to4 tunnel requires only a one-time configuration at the ISP, which makes the 6to4 relayservice available simultaneously to many enterprises.

6to4 tunnel usage has the following limitations:

• Independently managed NAT is not allowed along the path of the tunnel.

• You cannot easily implement multihoming.

• The 6to4 tunnel mechanism provides a /48 address block; no more addresses are available.

• Because 6to4 tunnels are configured many-to-one and tunnel traffic can originate from multipleendpoints, 6to4 tunnels can provide only overall traffic information to the ISP.

• The underlying IPv4 address determines the enterprise 6to4 IPv6 address prefix, so the migrationto native IPv6 requires renumbering the network.

• This solution is limited to static or BGP4+ routing.


26/55




Automat ic 6to4 Tunnel Configurat ion

Dynamips/Dynagen Topology files:IPV6_manual_tunnel_4_routers_init.net, IPV6_6to4_static_route_tunnel_final.net

Automatic 6to4 tunnel will be setup between two border routers R1 and R2. The IPv4 address of theborder router R1 is 172.16.101.1. The IPv4 address of the border router R2 is 172.16.102.1. IPv4connectivity between these two R1 and R2 is provided by IPv4 RIP routing protocol.

We need to derive 6to4 prefix from IPv4 addresses 172.16.101.1 and 172.16.102.1 by converting thedecimal components of the IPv4 address to hexadecimal and then prefixing “2002” to the resultinghexadecimal numbers. Look at the following conversion table:

R1 R2

DEC HEX DEC HEX

172 AC 172 AC

16 10 16 10

101 65 102 66

1 01 1 01



27/55




So the 6to4 prefix for the IPv6 R1 node in your network is 2002:AC10:6501:: and2002:AC10:6601::. What is a prefix length?

You can assign 2002:AC10:6501::/128 and 2002:AC10:6601::/128 on the tunnel interfaces. Let’s thinkwhat is going to happen:

1. Configure tunnel interfaces on both routers R1 and R2:

R1:i nt erf ace Tunnel 12no i p address

i pv6 addr ess 2002: AC10: 6501: : / 128

t unnel sour ce 172. 16. 101. 1t unnel mode i pv6i p 6t o4

R2:i nt erf ace Tunnel 12no i p address

i pv6 addr ess 2002: AC10: 6601: : / 128t unnel sour ce 172. 16. 102. 1t unnel mode i pv6i p 6t o4

Note: You specify only IPv4 tunnel source, the destination will be calculated, we’ll talk about thiscalculation in a minute.

2. Let’s try to ping the other end of the tunnel, run debug ipv6 packet detail meanwhile:

R1#ping 2002:AC10:6601::

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 2002: AC10: 6601: : , t i meout i s 2 seconds:

*Mar 1 04: 16: 37. 206: I Pv6: SAS pi cked sour ce 13: : 13: 1 f or 2002: AC10: 6601: : ( Ser i al 1/ 1)*Mar 1 04: 16: 37. 210: I Pv6: sour ce 13: : 13: 1 ( l ocal )*Mar 1 04: 16: 37. 210: dest 2002: AC10: 6601: :*Mar 1 04: 16: 37. 214: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, pr ot 58, hops 64, Rout enot f ound.

So it is complaining about route not being found. Let’s check the routing table:

R1#show ipv6 route



C 13: : / 64 [ 0/ 0]vi a : : , Ser i al 1/ 1

L 13: : 13: 1/ 128 [ 0/ 0]vi a : : , Ser i al 1/ 1

LC 2002: AC10: 6501: : / 128 [ 0/ 0]vi a : : , Tunnel 12

L FE80: : / 10 [ 0/ 0]



28/55





vi a : : , Nul l 0L FF00: : / 8 [ 0/ 0]

vi a : : , Nul l 0R1#

There is only one 2002:AC10:6501::/128 entry from the 2002 range, so the R1 does not have a route todest 2002:AC10:6601:: We need to direct packet with the destination dest 2002:AC10:6601:: to the tunnel12 interface so the tunnel can do its 6to4 encapsulation magic.

3. We are going to add a static route saying that if the destination starts with 2002 send it via tunnel 12interface:

R1( conf i g) #i pv6 r out e 2002: : / 16 t unnel 12

And try to ping again:

R1#ping 2002:AC10:6601::

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 2002: AC10: 6601: : , t i meout i s 2 seconds:

*Mar 1 04: 24: 52. 586: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 2002: AC10: 6601: :( Tunnel 12)*Mar 1 04: 24: 52. 590: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 24: 52. 594: dest 2002: AC10: 6601: : ( Tunnel 12)*Mar 1 04: 24: 52. 598: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng*Mar 1 04: 24: 52. 598: I Pv6: Sendi ng on Tunnel 12.

Of course you are not going to get any replies from R2 because you need to add static route there too. Butthe good thing is that R1 is sending via the Tunnel interface. Add ipv6 route 2002::/16 Tunnel12 on R2.

Ping from R1 again, and if you do the debug tunnel you will see this:

R1#ping 2002:AC10:6601::

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 2002: AC10: 6601: : , t i meout i s 2 seconds:. . . . .S

uccess r ate i s 0 per cent ( 0/ 5)

R1#ping 2002:AC10:6601::

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 2002: AC10: 6601: : , t i meout i s 2 seconds:! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 68/ 108/ 160 msR1#

*Mar 1 04: 28: 03. 558: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)*Mar 1 04: 28: 03. 562: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)*Mar 1 04: 28: 03. 566: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 04: 28: 03. 570: 2002: AC10: 6601: : - > 2002: AC10: 6501: : ( l en=60 t t l =64)

4. What if I want to ping something beyond the tunnel end point for example 24::24:2 which is a serialinterface of R2 connected to R4? Our educated guess tells us that it is not doing to work at this point


29/55





because R1 does not have a route to 24::24:2. We have to add a static route on R1, let’s do it and seewhat happens:

R1#deb ipv6 packet det

I Pv6 uni cast packet debuggi ng i s on ( detai l ed)R1#pi ng 24: : 24: 2

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 24: : 24: 2, t i meout i s 2 seconds:

*Mar 1 04: 33: 48. 038: I Pv6: SAS pi cked sour ce 13: : 13: 1 f or 24: : 24: 2 ( Ser i al 1/ 1)*Mar 1 04: 33: 48. 042: I Pv6: sour ce 13: : 13: 1 ( l ocal )*Mar 1 04: 33: 48. 046: dest 24: : 24: 2*Mar 1 04: 33: 48. 046: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, pr ot 58, hops 64, Rout enot f ound.

Let’s add the static route:

R1( conf i g) #i pv6 r out e 24: : / 64 tu 12

And ping again

R1#debug ipv6 packet

I Pv6 uni cast packet debuggi ng i s onR1#debug t unnel

T

unnel I nt erf ace debuggi ng i s on

R1#ping 24::24:2

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 24: : 24: 2, t i meout i s 2 seconds:

*Mar 1 04: 41: 51. 178: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 24: : 24: 2 ( Tunnel 12)

*Mar 1 04: 41: 51. 182: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 41: 51. 182: dest 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 51. 186: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng*Mar 1 04: 41: 51. 190: I Pv6: Sendi ng on Tunnel 12.*Mar 1 04: 41: 53. 190: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 53. 194: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 41: 53. 198: dest 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 53. 198: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng*Mar 1 04: 41: 53. 202: I Pv6: Sendi ng on Tunnel 12.*Mar 1 04: 41: 55. 206: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 55. 210: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 41: 55. 214: dest 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 55. 214: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng*Mar 1 04: 41: 55. 218: I Pv6: Sendi ng on Tunnel 12.

*Mar 1 04: 41: 57. 222: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 57. 226: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 41: 57. 230: dest 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 57. 230: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng*Mar 1 04: 41: 57. 234: I Pv6: Sendi ng on Tunnel 12.*Mar 1 04: 41: 59. 238: I Pv6: SAS pi cked sour ce 2002: AC10: 6501: : f or 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 59. 242: I Pv6: sour ce 2002: AC10: 6501: : ( l ocal )*Mar 1 04: 41: 59. 246: dest 24: : 24: 2 ( Tunnel 12)*Mar 1 04: 41: 59. 246: t r af f i c cl ass 0, f l ow 0x0, l en 100+0, prot 58, hops 64,or i gi nat i ng


30/55





*Mar 1 04: 41: 59. 250: I Pv6: Sendi ng on Tunnel 12.Success r ate i s 0 percent ( 0/ 5)

R1#

As you noticed the forwarding of IPv6 packet to 24::24:2 destination is fine now, but the tunneling is nottriggered. Why? At this point R1 does not have enough information to encapsulate IPv6 packet using 6to4scheme. It has a configured IPv4 tunnel source 172.16.101.1 (from the tunnel configuration), but it doesnot know what IPv4 address should be used for a tunnel destination. The IPv4 address is derived from theR2’s tunnel address ipv6 address 2002:AC10:6601::/128, which is 172.16.102.1Therefore you have to create a static route to 24::/64 not via the tunnel interface and via the next hop IPv6address 2002:AC10:6601::

R1( conf i g) #no i pv6 r out e 24: : / 64 t u 12R1( conf i g) #i pv6 r out e 24: : / 64 2002: AC10: 6601: :R1( conf i g) #

Important! Networks that are reachable via 6to4 IPv6 tunnels must be listed with the 6to4 like next hopIPv6 address.

S 24: : / 64 [ 1/ 0]vi a 2002: AC10: 6601: :

Try to ping it again and run only debug tunnel otherwise the output of debug ipv6 packet makes yourscreen too busy.

R1#debug tunnel

Tunnel I nt er f aceR1#ping 24::24:2

debuggi ng i s on

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 24: : 24: 2, t i meout i s 2 seconds:! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 88/ 105/ 128 msR1#*Mar 1 04: 48: 55. 086: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)*Mar 1 04: 48: 55. 090: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)*Mar 1 04: 48: 55. 094: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 04: 48: 55. 098: 24: : 24: 2 - > 2002: AC10: 6501: : ( l en=60 t t l =64)

5. You can configure a static default route 0::/0 to provide a route to all IPv6 destinations and let’s do it tofinish this 6to4 tunnel configuration with the static routes:

R1#conf t

R1( conf i g) #no i pv6 r out e 24: : / 64 2002: AC10: 6601: :R1( conf i g) #i pv6 r out e 0: : / 0 2002: AC10: 6601: :R1( conf i g) #

R1#show ipv6 route




31/55




S : : / 0 [1/0]vi a 2002: AC10: 6601: :

R1#ping 24::24:2


Can we avoid configuring a static route to 2002::/16 via tunnel 12? Yes if we provide a routing entry for all6to4 tunnel endpoints via connected IPv6 entry.

Let’s find out common bits of IPv6 addresses of both tunnel interfaces of R1 and R2

2002:AC10:6501:: 0010000000000010: 1010110000010000: 0110010100000001::2002:AC10:6601:: 0010000000000010: 1010110000010000: 0110011000000001::

Green highlighted area is 38 bits that are common for both addresses. So if we specify addresses2002:AC10:6501::/38 and 2002:AC10:6601::/38 on the tunnel interfaces R1 and R2 will know that theother end is reachable via connected /38 network. /38 is the longest connected prefix you can configure toprovide reachability to these two specific IPv6 addresses. Of course you can go with the less specificprefixes /37, /36, etc. as well.



32/55





1. Reconfigure IPv6 address on both ends of the tunnel:

R1( conf i g) #i nt erf ace Tunnel 12R1( conf i g- i f ) # i pv6 addr ess 2002: AC10: 6501: : / 38R1( conf i g- i f ) #

R2( conf i g) #i nt t u12R2( conf i g- i f ) #i pv6 addr ess 2002: AC10: 6601: : / 38

2. Remove a static route to tunnel interface:

R1(conf i g)#no i pv6 r out e 2002: : / 16 Tunnel 12

R2(conf i g)#no i pv6 r out e 2002: : / 16 Tunnel 12

3. Verify if you still can ping 24::24:2 from R1:

R1#ping 24::24:2


And you can because you have a prefix in the routing table, that provides reachability to the other end ofthe tunnel 2002::AC10:6601::/38

R1#show ipv6 route



S : : / 0 [1 /0]vi a 2002: AC10: 6601: :

C 13: : / 64 [ 0/ 0]vi a : : , Ser i al 1/ 1

L 13: : 13: 1/ 128 [ 0/ 0]vi a : : , Ser i al 1/ 1

C 2002: AC10: 6400: : / 38 [ 0/ 0]vi a : : , Tunnel 12

L 2002: AC10: 6501: : / 128 [ 0/ 0]vi a : : , Tunnel 12

L FE80: : / 10 [ 0/ 0]vi a : : , Nul l 0

L FF00: : / 8 [ 0/ 0]vi a : : , Nul l 0

R1#

What if we do not want to use any static routes? Is it possible with 6to4 tunnels? The answer is yes, butwith the BGP routing protocol only. Since IPv6 IGPs such as OSPF, RIP, EIGRP form and exchangeupdates between the IPv6 link local interfaces, the 6to4 encapsulation scheme with the derived IPv4address does not work. On the other hand, the BGP routing process uses TCP peers to exchange therouting updates and the TCP sessions can be established between any IPv6 addresses.


33/55




Let’s consider a following scenario:

Dynamips/Dynagen Topology files:IPV6_manual_tunnel_4_routers_init.net, IPV6_6to4_BGP_tunnel_final.net

R1 and R2 are in BGP AS1 and AS2 respectively and will form peer relationship over 6to4 tunnel. BGP willbe used to provide reachability to two IPv6 RIP domains. The ultimate goal is to ping from 13::13:3 of R3the 24::24:4 address of R4. No static routes will be used in this scenario.

1. Remove the default static routes from R1 and R2:

R1( conf i g) #no i pv6 r out e : : / 0 2002: AC10: 6601: :

R2( conf i g) #no i pv6 r out e : : / 0 2002: AC10: 6501: :

2. Configure BGP on both routers and peer them using the IPv6 addresses configured on the 6to4tunnel:

R1(conf i g)#r out er bgp 1R1( conf i g- r out er) #nei ghbor 2002: AC10: 6601: : r emote- as 2R1( conf i g- r out er) #



34/55





R2(conf i g)#r out er bgp 2

R2( conf i g- r out er) #nei ghbor 2002: AC10: 6501: : r emote- as 1

In a moment you should get the following status messages:

R1( conf i g- rout er) #*Mar 1 01: 10: 13. 483: %BGP- 5- ADJ CHANGE: nei ghbor 2002: AC10: 6601: : Up

R2#*Mar 1 01: 10: 12. 651: %BGP- 5- ADJ CHANGE: nei ghbor 2002: AC10: 6501: : Up

3. Configured IPv6 RIP instance on the interfaces on links between R1-R3 and R2-R4.

R1( conf i g) #i pv6 uni cast - r out i ngR1( conf i g) #i pv6 r out er r i p RI PoTUR1( conf i g- r t r ) #i nt s1/ 1

R1( conf i g- i f ) #i pv6 r i p RI PoTU enabl eR1( conf i g- i f ) #

R2( conf i g) #i pv6 uni cast - r out i ngR2( conf i g) #i pv6 r out er r i p RI PoTUR2( conf i g- r t r ) #i nt s1/ 1R2( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

R3( conf i g) #i pv6 uni cast - r out i ngR3( conf i g) #i pv6 r out er r i p RI PoTUR3( conf i g- r t r ) #i nt s1/ 0R3( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

R4( conf i g) #i pv6 uni cast - r out i ngR4( conf i g) #i pv6 r out er r i p RI PoTU

R4( conf i g- r t r ) #i nt s1/ 0R4( conf i g- i f ) #i pv6 r i p RI PoTU enabl e

4. Mutually redistribute BGP and RIP on R1 and R2 and activate the BGP IPv6 updates exchange.

R1(conf i g)#r out er bgp 1R1( conf i g- r out er) #addr ess- f ami l y i pv6 uni castR1( conf i g- r out er- af ) #nei ghbor 2002: AC10: 6601: : act i vat eR1( conf i g- r out er - af ) #r edi st r i but e r i p RI PoTU i ncl ude- connect edR1( conf i g- r out er - af ) #i pv6 r out er r i p RI PoTUR1( conf i g- r t r ) #r edi st r i but e bgp 1 i ncl ude- connect edR1( conf i g- r t r ) #

R2(conf i g)#r out er bgp 2R2( conf i g- r out er) #addr ess- f ami l y i pv6 uni castR2( conf i g- r out er- af ) #nei ghbor 2002: AC10: 6501: : act i vat eR2( conf i g- r out er - af ) #r edi st r i but e r i p RI PoTU i ncl ude- connect edR2( conf i g- r out er - af ) #i pv6 r out er r i p RI PoTUR2( conf i g- r t r ) #r edi st r i but e bgp 2 i ncl ude- connect edR2( conf i g- r t r ) #


35/55





Check the IPv6 BGP tables and IPv6 forwarding routing table on both routers R1 and R2:

R1#sh bgp ipv6 unicastBGP tabl e ver si on i s 3, l ocal r out er I D i s 172. 16. 101. 1St at us codes: s suppr essed, d damped, h hi st ory, * val i d, > best , i - i nt er nal ,

r RI B- f ai l ure, S Stal eOr i gi n codes: i - I GP, e - EGP, ? - i ncompl et e

Net work Next Hop Met r i c LocPr f Wei ght Path*> 13: : / 64 : : 0 32768 ?*> 24: : / 64 2002: AC10: 6601: :

0 0 2 ?R1# R1#show ipv6 route bgp



B 24: : / 64 [ 20/ 0]vi a 2002: AC10: 6601: :

R1# R2#sh bgp ipv6 unicast

BGP tabl e ver si on i s 3, l ocal r out er I D i s 172. 16. 102. 1St at us codes: s suppr essed, d damped, h hi st ory, * val i d, > best , i - i nt er nal ,

r RI B- f ai l ure, S Stal eOr i gi n codes: i - I GP, e - EGP, ? - i ncompl et e

Net work Next Hop Met r i c LocPr f Wei ght Path*> 13: : / 64 2002: AC10: 6501: :

0 0 1 ?*> 24: : / 64 : : 0 32768 ?

R2#R2#show ipv6 route bgpI Pv6 Rout i ng Tabl e - 7 ent r i esCodes: C - Connect ed, L - Local , S - St ati c, R - RI P, B - BGP


B 13: : / 64 [ 20/ 0]vi a 2002: AC10: 6501: :

R2#

R1 and R2 have remote IPv6 RIP prefixes learned via the 6to4 tunnel IPv6 address as a next hop, that’swhat we want to see in the routing table.

5. Check IPv6 routing tables on R3 and R4 and if they look good try to ping R4 from R3:




R 24: : / 64 [ 120/ 2]vi a FE80: : CE00: 1FF: FEFC: 0, Ser i al 1/ 0

R3#


36/55





R4#sho ipv6 route rip


R 13: : / 64 [ 120/ 2]vi a FE80: : CE01: 1FF: FEFC: 0, Ser i al 1/ 0

R4# R3#ping 24::24:4

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o 24: : 24: 4, t i meout i s 2 seconds:! ! ! ! !Success rat e i s 100 per cent ( 5/ 5), r ound- t r i p mi n/ avg/ max = 60/ 160/ 284 msR3#


37/55





1.5 IPv4 Compatib le IPv6 Tunnel

Characteristics of the IPv4 compatible 6to4 tunnel

• Allows isolated IPv6 domains to be connected over an IPv4 network to remote IPv6 networks.

• The tunnel is not point-to-point; it is point-to-multipoint.

• The IPv4 address embedded in the IPv6 address is used to find the other end of the automatictunnel.

• Using IPv4-compatible tunnels is an easy method to create tunnels for IPv6 over IPv4, but thetechnique does not scale for large networks.

• IPv4-compatible tunnels were initially supported for IPv6, but are being deprecated. Ciscorecommends that you use the IPv6 ISATAP tunneling technique

• This solution is limited to static or BGP4+ routing.

IPv4 Compatible IPv6 Tunnel Configuration

Dynamips/Dynagen Topology files:IPV6_manual_tunnel_4_routers_init.net, IPV4_IPV6_BGP_tunnel_final.net

IPv4 compatible tunnel will be setup between two border routers R1 and R2. The IPv4 address of theborder router R1 is 172.16.101.1. The IPv4 address of the border router R2 is 172.16.102.1. IPV4connectivity between these two R1 and R2 is provided by IPv4 RIP routing protocol.

IPv4 addresses 172.16.101.1 and 172.16.102.1 will be used for the tunnel source on R1 and R2respectively. The tunnel destination s automatically determined by the IPv4 address in the low-order 32bits of an IPv4-compatible IPv6 address. Specifically, the IPv6 prefix 0:0:0:0:0:0 is concatenated to anIPv4 address (in the format 0:0:0:0:0:0:A.B.C.D or ::A.B.C.D) to create the IPv4-compatible IPv6 address.


38/55




1. Configure IPv4 compatible IPv6 Tunnel 12 on both routers R1 and R2:

R1( conf i g) #i nt erf ace Tunnel 12R1( conf i g- i f ) # no i p addr essR1( conf i g- i f ) # no i p redi r ectsR1( conf i g- i f ) # t unnel sour ce 172. 16. 101. 1R1( conf i g- i f ) # t unnel mode i pv6i p aut o- t unnel

R2( conf i g) #i nt erf ace Tunnel 12R2( conf i g- i f ) # no i p addr essR2( conf i g- i f ) # no i p redi r ectsR2( conf i g- i f ) # t unnel sour ce 172. 16. 102. 1R2( conf i g- i f ) # t unnel mode i pv6i p aut o- t unnel

Check t he pr oper t i es of i nt er f ace and I Pv6 i nt er f ace:

R1#show int tunnel 12 Tunnel 12 i s up, l i ne prot ocol i s up

Hardware i s TunnelMTU 1514 byt es, BW 9 Kbi t , DLY 500000 usec,


Tunnel sour ce 172. 16. 101. 1, dest i nat i on UNKNOWN Tunnel pr ot ocol / t r anspor t I Pv6 aut o- t unnel

Fast t unnel i ng enabl ed



39/55





Tunnel t r ansmi t bandwi dt h 8000 ( kbps) Tunnel r ecei ve bandwi dt h 8000 ( kbps)

Last i nput 00: 05: 51, out put 00: 05: 51, out put hang neverLast cl ear i ng of " show i nt erf ace" counter s neverI nput queue: 0/ 75/ 0/ 0 (si ze/ max/ dr ops/ f l ushes) ; Tot al out put dr ops: 0Queuei ng str ategy: f i f oOutput queue: 0/ 0 (s i ze/ max)5 mi nut e i nput r ate 0 bi t s/ sec, 0 packet s/ sec5 mi nut e output r ate 0 bi t s/ sec, 0 packets/ sec

10 packets i nput, 1400 byt es, 0 no buf f erRecei ved 0 br oadcast s, 0 runt s, 0 gi ant s, 0 thrott l es0 i nput err ors, 0 CRC, 0 f r ame, 0 over r un, 0 i gnored, 0 abort16 packets out put , 1752 byt es, 0 underr uns0 out put err ors, 0 col l i s i ons, 0 i nt er f ace reset s0 out put buf f er f ai l ures, 0 out put buf f ers swapped out

R1# R1#show ipv6 int tunnel 12

Tunnel 12 i s up, l i ne prot ocol i s up

I Pv6 i s enabl ed, l i nk- l ocal addr ess i s FE80: : AC10: 6501Gl obal uni cast addr ess( es) :

: : 172. 16. 101. 1, subnet i s : : / 96 [ NEG] J oi ned gr oup address ( es) :

FF02: : 1FF02: : 2FF02: : 1: FF10: 6501

MTU i s 1480 byt esI CMP er r or messages l i mi t ed t o one every 100 mi l l i secondsI CMP r edi r ect s are enabl edND DAD i s not suppor t edND r eachabl e t i me i s 30000 mi l l i secondsHosts use st atel ess aut oconfi g f or addresses.

R1#

You will see similar outputs on R2.

2. On R1 ping the tunnel endpoint of R2 and run debug tunnel:

R1#debug tunnel

Tunnel I nt er f ace debuggi ng i s on

R1#ping ::172.16.102.1

Type escape sequence t o abort .Sendi ng 5, 100- byt e I CMP Echos t o : : 172. 16. 102. 1, t i meout i s 2 seconds:! ! ! ! !Success r ate i s 100 percent ( 5/ 5), r ound-t r i p mi n/ avg/ max = 64/ 96/ 120 msR1#*Mar 1 00: 27: 44. 383: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)*Mar 1 00: 27: 44. 387: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)

*Mar 1 00: 27: 44. 391: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 00: 27: 44. 395: : : 172. 16. 102. 1 - > : : 172. 16. 101. 1 ( l en=60 t t l =64)*Mar 1 00: 27: 44. 495: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)*Mar 1 00: 27: 44. 499: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)*Mar 1 00: 27: 44. 503: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 00: 27: 44. 503: : : 172. 16. 102. 1 - > : : 172. 16. 101. 1 ( l en=60 t t l =64)*Mar 1 00: 27: 44. 563: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)


40/55





*Mar 1 00: 27: 44. 567: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)

*Mar 1 00: 27: 44. 571: Tunnel 12: decapsul ated I Pv6/ I P packet*Mar 1 00: 27: 44. 571R1#: : : 172. 16. 102. 1 - > : : 172. 16. 101. 1 ( l en=60 t t l =64)*Mar 1 00: 27: 44. 667: Tunnel 12: I Pv6/ I P to cl assi f y 172. 16. 102. 1- >172. 16. 101. 1 (l en=120t t l =254 t os=0x0)*Mar 1 00: 27: 44. 671: Tunnel 12: t o decaps I Pv6/ I P packet 172. 16. 102. 1- >172. 16. 101. 1( l en=120, t t l =254)*Mar 1 00:

Ipv6 Ipv4 Tunnel

Documents

Transcript of Ipv6 Ipv4 Tunnel